Application Guide

Refrigerant Piping Systems

I – Refrigerant Piping
II – High Rise Applications
III – Hot Gas Bypass
 Application
Guide

Index Tables and Charts

Page Page
Introduction␣ ␣ ............................................................................................................... 3 Table “A” – Liquid Line Selection
for R-22 Systems ................................... 7
General Information␣ ................................................................................................. 4
Figure 1 – Underground Conduit ............. 8
Chapter I – Refrigerant Piping Table “B” – R-22 Suction
Liquid Lines for Split Cooling and Heat Pump Systems .............................................. 5 Line Selection ..................................... 10
Liquid Line Selection Table For R-22 Systems ............................................................. 7 Table “C” – Equivalent Lengths .... 10 & 17
Table “E-1” – Refrigerant Piping and
Suction Lines for Split Cooling and Heat Pump Systems ........................................... 8
Accessories for Reciprocating and
Underground Conduit ................................................................................................... 8 Scroll Compressors ............................ 12
Equivalent Length (Ft.) of Non-Ferrous Valves and Fittings (Brazed) ....................... 10 Table “E-2” – Thermal Expansion
Suction Line Selection Table (R-22) ............................................................................ 10 Valve for Cooling and Heat
Piping Limits ................................................................................................................ 11 Pump Units ......................................... 12
Refrigerant Piping and Accessories for Reciprocating and Scroll Compressors ..... 12 Figure 2 – Typical Cooling System ......... 13
R-410A Refrigerant ...................................................................................................... 15 Figure 3 – Thermal Bulb Location .......... 13
Figure 4 – Tubing Hints ........................... 13
Chapter II – High Rise Systems Figure 5 – Air Conditioning Formulas .... 14
High Rise Heat Pump Systems (R-22 and R-410A) .................................................... 18 Figure 6 – R-410 Temperature and
Subcooling Heat Exchangers ...................................................................................... 20 Pressure Chart .................................... 15
Table “G” – Pounds of R-410A
Chapter III – Hot Gas Bypass Required for Line Sets ........................ 15
Hot Gas Bypass Capacity Modulation ........................................................................ 22 Table “A-R” – Liquid Line Selection
Recommended Piping Hook-Up for Hot Gas Bypass ................................................ 23 for R-410A Systems ............................ 16
Selecting The Hot Gas Bypass Valve .......................................................................... 25 Table “B-R” – R-410A Suction
Quick Selection Table For Hot Gas Bypass Valves ..................................................... 25 Line Selection ..................................... 17
How To Estimate Minimum Loads .............................................................................. 30 Table “D” – Heat Exchanger Details ...... 18
Refrigerant Piping Worksheet .............................................................................. 31 – 32 Figure 7 – Heat Exchanger Piping .......... 19
Figure 8 – High Rise Schematic .............. 20
Table “H” – Capillary Tube Selection
Table for R-22 Subcooler .................... 21
Table “I” – Capillary Tube Selection
Table for R-410A Subcooler ............... 21
Figure 9 – Hot Gas Bypass Hook-up ....... 23
Figure 10 – Bypass Valve ........................ 24
Table “E” – Selection Table Hot Gas ...... 25
This manual is dedicated to improving system performance and reliability. A
properly designed refrigerant piping system ensures oil return, minimizes Table “F” – Bypass Valve Capacities ...... 25
capacity losses, and provides for maximum equipment life. Chart “J” – Pressure Drop in
R-22 Vapor Lines ................................. 26
Our thanks to the following for their valuable contributions:
Figure 11 – Auxiliary Side Connector .... 27
• Dave Donnelly • Terry Ryan
Figure 12 – H.G.B.V. Multipliers ............. 27
• Chuck Erlandson • Jim Sharp
Figure 13 – Hot Gas Solenoid Valves ..... 28
• Marion Houser • Greg Walters
Figure 14 – Liquid Line Solenoid
• Red Roley • Richard Welguisz
Valves .................................................. 29

© American Standard 2000 2 32-3009-03

 Application
Guide

Introduction given tonnage results in the lowest

losses in capacity and efficiency consis-
The purpose of this manual is to tent with proper oil return. Shorter
assist the user in the proper selection tubing runs may provide acceptable
of liquid lines and suction lines for losses with a smaller diameter.
straight cooling and heat pump split
systems (Chapter I). Chapter II covers Hot gas lines are somewhat less critical
High Rise Applications and Chapter III insofar as pressure drops and oil return
covers Hot Gas Bypass (Capacity are concerned. In the case of a heat
Modulation). pump, the gas line is sized as a suction
line, and although it is somewhat over-
Careful use of the tables and charts in sized as a discharge line, our experience
Chapter I will ensure: over many years, indicates that oil return
• minimum pressure drops, is not a problem, within the published
• adequate oil return, limits. Dedicated hot gas lines, such as
• maximum system reliability, hot gas lines for hot gas bypass, are
covered in Chapter III of this manual.
• delivery of 100% liquid to the
metering device. The new, Windows® based piping
program has been released, for both
New selection tables are included for
Trane and American Standard. Pub.
liquid and suction lines covering
No. 32-3312-01 covers Trane, American
equivalent lengths up to 240 ft.
Standard and 50 Hz equipment.
The philosophy in designing a refriger-
The new piping program is very user
ant piping system can be summed up
friendly and is highly recommended,
as follows:
since it:
Liquid lines should be sized as small • saves valuable time,
as possible without exceeding the rec- • reduces errors,
ommended maximum pressure drop, • reminds the user of the required
of 35 PSI for R-22 or 50 PSI for R-410A. accessories,
Liquid line pressure drop calculations • generates customer confidence,
must include friction loss, liquid lifts
and refrigerant accessories (solenoid • establishes the user as a knowledge-
valves, etc.). able expert.

There is no penalty for pressure drop Information provided by the program

in a liquid line, provided it does not includes:
exceed 35 PSI (50 PSI with R-410A). • Liquid and suction line sizes
The smallest diameter that meets this • Liquid and suction line
35 PSI criteria results in better system pressure drops
reliability (fewer pounds of refrigerant
• Net system capacity
to cause potential damage to the com-
pressor). Note that the 35 PSI allowance • Approximate system charge
is based on 10 degrees of subcooling • Required system accessories
(no liquid receiver.) Both Trane and • High rise requirements
American Standard U.P.G. units meet
this criteria. • Reciprocating and scroll compressor
requirements
Since suction line pressure drop does • R-22 and R-410A refrigerants
reduce capacity and efficiency, suction • Linear lengths to 200 ft.
lines should be sized as large as pos-
sible, while still maintaining sufficient • Linear lifts to 200 ft.
velocity for oil return. All tubing sizes • Excellent print-outs
listed in Table “B” will provide oil return.
Using the largest diameter listed for a

32-3009-03 3
 Application
Guide

General Information B — Oil return must always be consid- 3 – There is no direct penalty for pres-
ered since some oil is continually being sure drop in a liquid line provided
The four prime considerations in design- circulated with the refrigerant and must that 100% liquid is being delivered
ing a refrigerant piping system are: be returned to the compressor. If the to the expansion device, and that
A – System Reliability recommended suction line sizes are the liquid pressure available to the
B – Oil Return used, no oil return problems should be expansion device is adequate to
encountered with split systems and no produce the required refrigerant
C – Friction Losses (Pressure Drop) traps are recommended. flow. Pressure drop or gain due to
D – Cost vertical lift must be added to the friction
C — Pressure drop or friction losses are loss in liquid lines to determine the total
A — The piping system can affect important from a performance stand- pressure drop. The acceptable pressure
system reliability in a number of ways: point. The following general statements drop in the liquid line for equipment
• Oversized liquid lines significantly point out the effects of pressure drop in through 10 tons is 35 PSI for R-22 sys-
increase the amount of refrigerant the various components of the refriger- tems and 50 PSI for R-410A systems.
in the system, and thus creating the ant piping system.
potential for slugging, oil dilution, D — Cost is an obvious consideration
or other damage to the compressor. 1 – Pressure drop in the suction line and dictates that the smallest tubing
reduces system capacity significantly possible be used that will result in a
• Undersized liquid lines and the and increases power consumption per system with acceptable friction losses.
associated “flashing” of refrigerant ton. The most generally accepted value
causes starving of the evaporator coil. for pressure drop in a suction line is a The following pages cover the selection
The results can be significant loss in pressure drop equivalent to 2°F (approx. of liquid lines and suction lines for split
capacity, frosted evaporator coil, high 3 PSI with R-22 in the air conditioning heat pump and cooling systems.
superheat etc. range of evaporating temperatures or
approx. 5 PSI for R-410A). As tubing runs It is recommended that the user read
• Oversized suction lines will result become longer, it is inevitable that the all of Chapter I in order to better under-
in refrigerant velocities too low to ASHRAE recommendation will be stand the Tables, Charts, etc.
provide adequate oil return to the exceeded, at times. This trade-off, of
compressor. somewhat greater suction line losses, See the Index for a complete listing,
for adequate oil return is an absolute including page number, for all tables,
• Undersized suction lines reduce must, in order to preserve system charts, etc.
capacity and efficiency and contribute reliability.
to high superheat. All installations must conform to any
2 – Pressure drop in hot gas lines re- codes or regulations applying at the
• Excessive refrigerant line length duces system capacity to a somewhat site. The Safety Code for Mechanical
reduces system capacity and effi- lesser degree and increases power Refrigeration, ASA-B-9-1 and the Code
ciency, as well as system reliability consumption to a slightly lesser degree for Refrigeration Piping, ASA-B31.5
(excessive refrigerant charge). than does pressure drop in suction lines. should serve as your guide toward a
Keep refrigerant lines as short as Since the only hot gas lines we are con- safe piping system.
conditions permit! cerned with are in heat pump systems
where they also serve as suction lines,
we will treat them as suction lines. (See
Chapter III in this manual for information
on hot gas lines for hot gas bypass.)

4 32-3009-03
 Application
Guide

CHAPTER I must be avoided. However, it prevails The saturation pressure for R-22 at 110°F
only when outdoor temperatures are is approx. 226 PSIG Substracting 226
Refrigerant Piping relatively cool and under conditions PSIG from the 260 PSIG condensing
when air conditioning for most residen- pressure, gives us a difference of 34 PSI.
tial applications is not required. While this pressure difference is 1 PSI
Liquid Lines for
less than the 35 PSI obtained with the
Split Cooling and Any situation such as an unusually long 125°F example used in earlier versions
liquid line or a large difference in eleva-
Heat Pump Systems tion between the indoor and outdoor
of this manual, we will continue to use
35 PSI as the maximum liquid line pres-
The purpose of the liquid line is to sections may require consideration as sure drop. (A drop in liquid line tempera-
convey liquid refrigerant from the con- discussed further below. ture of 1/3°F by natural cooling, will
denser to the expansion device such as
provide the needed 1 PSI.)
the expansion valve or FCCV Accutron.TM The flashing of refrigerant to gas will
The expansion device in turn throttles occur if the refrigerant absorbs heat Note that the above mentioned tempera-
the refrigerant from the high side pres- in the liquid line so that it is no longer tures of 120°F and 110°F represent pres-
sure as it exists at the entrance to the subcooled or if its pressure is reduced sures of 418 PSIG and 365 PSIG with
device to the relatively low evaporator below the saturation pressure corre- R-410A, a difference of 53 PSI. For the
pressure. The high side pressure varies sponding to its temperature. present, we will limit R-410A liquid line
through a wide range with the cooling pressure drop to 50 PSI.
load and the outdoor temperature. The Normally, the liquid line temperature is The foregoing has shown how to
expansion device has to handle this above that of the surrounding ambient figure the liquid line pressure drop
situation and the fact that a particular so there is no “flashing” as a result of and indicated that the heat loss to the
pressure drop is required to produce temperature rise and usually there is surroundings help to maintain adequate
the flow through the liquid line is not enough cooling of the refrigerant to subcooling. The amount of refrigerant
especially critical providing two compensate for the fact that the pressure in the system governs the amount of
conditions exist. gradually drops to maintain flow. In spe- subcooling of the liquid as it leaves
cial cases where the liquid line is run the condenser. The appropriate installa-
The first condition is that the liquid line through hot attics or other heat sources tion and charging instructions should
transports the refrigerant completely as the liquid line should be insulated. be followed.
liquid and not allow the refrigerant to
flash partly into gas. This requires that Table “C,” page 10, lists the equivalent With regard to whether adequate head
the liquid temperature be lower than the length of fittings, which must be added pressure is available at the expansion
temperature which causes refrigerant to to the linear length of the tubing to device to give the required flow, note
vaporize at the pressure prevailing lo- obtain the equivalent length of the line. that an unusually high pressure drop in
cally in the tube, that is, the refrigerant a liquid line due to long lengths or large
must be subcooled throughout the The pressure loss due to vertical lift differences in elevation, has the same
length of the liquid line. (evaporator above the condenser) de- effect as a reduced head pressure due
pends on the difference in level between to cooler outdoor temperatures entering
The second condition is that the pres- the metering device and condenser (or the air cooled condenser. Typically each
sure and amount of subcooling at the receiver) and on the density of the refrig- additional 10 PSI drop in pressure in the
entrance to the expansion device must erant. At normal liquid line temperatures liquid line means that the minimum out-
be adequate for the device to pass the with R-22 the static pressure drop will be door temperature at which the system
required flow into the evaporator to 0.50 PSI per foot of lift (.43 PSI per foot will perform satisfactorily is raised by
suit the cooling load condition. If not, with R-410A). 3 degrees. Allowance for this is signifi-
the evaporator is starved for refrigerant. cant only for unusual applications
This may cause one part to freeze ice As an example, consider an air-cooled where cooling is required at low outdoor
and gradually choke off the indoor air- R-22 system with 95°F air entering the temperatures. Performance for such
flow even though other parts of the condenser, the condensing temperature conditions is published in the Product
evaporator are warm for lack of refriger- is 120°F (approx. 260 PSI). Manual and is based on 25 feet of line as
ant. When the evaporator is starved, the After being subcooled in the condenser, used for Standard Ratings. For marginal
reduced cooling effect reduces the head the liquid R-22 leaves the condenser at applications where a Head Pressure
pressure in the condenser and through- 110°F. Assuming the pressure at the Control accessory is under consider-
out the liquid line, which tends still fur- condenser outlet is the same as the con- ation, the effect of liquid line pressure
ther to reduce the refrigerant flow. This densing pressure of approx. 260 PSIG, drop should be considered.
inadequate head pressure situation the liquid R-22 has been subcooled 10°F.

32-3009-03 5
Application
Guide

There are other considerations with The importance of a properly charged

regard to the installation of liquid lines. system cannot be over-emphasized
when liquid line pressure drops are
The use of long radius ells can reduce being considered. Proper subcooling
the equivalent length of a line and thus is dependent on the proper refrigerant
reduce the friction loss. charge and the maximum allowable
pressure drop in a liquid line is directly
Do not add a drier or filter in series with dependent on the amount of subcooling
the factory installed drier as the added obtained.
pressure drop may cause “flashing” of
liquid refrigerant. If the equivalent length of a liquid line
is excessive or if vertical lifts use up a
If a system does not have a liquid large share of the acceptable pressure
receiver, the amount of the refrigerant drop, it may be necessary to go to the
charge in the system can have a signifi- next larger tube size in order to keep the
cant effect on the amount of subcooling pressure drop within acceptable limits.
obtained, which in turn determines the In some instances a slightly oversized
pressure drop which can be tolerated in expansion valve can compensate for
the liquid line. (An undercharged system lower than normal liquid pressure at the
will have little or no subcooling while an valve. (Subcooling must be adequate
over-charged system will have high con- to prevent “flashing” of liquid R-22 to
densing temperatures because of the vapor.) Do not oversize liquid lines any
loss of effective condensing surface.) more than necessary because this adds
very significantly to the amount of refrig-
Pressure drop due to the weight of the erant in the system which adds cost and
refrigerant is no problem if the evapora- increases the danger of slugging. See
tor coil is below the condenser, as the page 11 for tubing limits.
weight of the liquid, in this case, causes
an increase in pressure and aids in Since refrigerant oil is miscible with
subcooling. liquid R-22, at the temperatures encoun-
tered in the liquid line, there is normally
Table “A” is used to select a liquid line. no problem with oil return in liquid lines.
The pressure drop is given for the vari-
ous equivalent lengths (up to 240 eq. ft.). The remaining portion of Chapter I
includes:
The actual selection of a liquid line is
covered on page 7. • Liquid Line Selection – page 7

Note that equivalent lengths are used • Suction Line Selection – pages 8, 9
when calculating pressure drops. Actual and 10
(linear) lengths are used when calculat- • Refrigerant Piping Limits – page 11
ing pounds of R-22 in a line set. (An
elbow contains about the same amount • Piping Accessories for Scroll and
of R-22 as does the same length of Reciprocating Compressors – page 12
straight tubing.) • Tubing Hints – page 13
Table “C,” page 10, lists equivalent • Air Conditioning Formulas – page 14
lengths for elbows, etc. for pressure
drop calculations. • R-410A Refrigerant – pages 15, 16
and 17
In addition to friction loss, any pres- Note: A worksheet for Manual Calculations is provided
sure drop due to liquid lift must be on page 31.
accounted for (.5 PSI per foot of lift
for R-22 systems, .43 PSI per foot
with R-410A).

6 32-3009-03
 Application
Guide

Table “A”
Liquid Line Selection Table For R-22 Systems
Maximum Allowable Liquid Line Pressure Drop .................................................................................................. = 35 PSI
Subtract .5 PSI for each foot of Liquid Lift (if any) ......................................................................................................
Do Not Exceed this value when selecting Liquid Line. ...............................................................................................
Pressure Drop (PSI)
Total Equivalent Length
Tube Rated
O.D. BTUH 20' 40' 60' 80' 100' 120' 140' 160' 180' 200' 220' 240'
15000 4.3 8.7 13.0 17.4 21.7 26.0 30.4 34.7 — — — —
1/4" 18000 6.0 12.0 18.1 24.1 30.1 — — — — — — —
24000 10.2 20.3 30.5 — — — — — — — — —
15000 1.1 2.3 3.4 4.6 5.7 6.8 8.0 9.1 10.3 11.4 12.5 13.7
18000 1.6 3.2 4.7 6.3 7.9 9.5 11.1 12.6 14.2 15.8 17.4 19.0
5/16" 24000 2.7 5.3 8.0 10.6 13.3 16.0 18.6 21.3 23.9 26.6 29.3 31.9
30000 4.0 8.0 11.9 15.9 19.9 23.9 27.9 31.8 — — — —
36000 5.5 11.1 16.6 22.2 27.7 33.2 — — — — — —
42000 7.3 14.6 22.0 29.3 — — — — — — — —
18000 .6 1.1 1.7 2.2 2.8 3.4 3.9 4.5 5.0 5.6 6.2 6.7
24000 .9 1.9 2.8 3.8 4.7 5.6 6.6 7.5 8.5 9.4 10.3 11.3
30000 1.4 2.8 4.2 5.6 7.0 8.4 9.8 11.2 12.6 14.0 15.4 16.8
3/8" 36000 1.9 3.9 5.8 7.8 9.7 11.6 13.6 15.5 17.5 19.4 21.3 23.3
42000 2.6 5.1 7.7 10.2 12.8 15.4 17.9 20.5 23.0 25.6 28.2 30.7
48000 3.3 6.5 9.8 13.0 16.3 19.6 22.8 26.1 29.3 32.6 — —
60000 4.9 9.8 14.7 19.6 24.5 29.4 34.3 — — — — —
72000 6.8 13.7 20.5 27.4 34.2 — — — — — — —
36000 .4 .8 1.2 1.6 2.0 2.4 2.8 3.2 3.6 4.0 4.4 4.8
42000 .5 1.0 1.6 2.1 2.6 3.1 3.6 4.2 4.7 5.2 5.7 6.2
48000 .7 1.3 2.0 2.6 3.3 4.0 4.6 5.3 5.9 6.6 7.3 7.9
1/2" 60000 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0
72000 1.4 2.8 4.1 5.5 6.9 8.3 9.7 11.0 12.4 13.8 15.2 16.6
90000 2.1 4.2 6.2 8.3 10.4 12.5 14.6 16.6 18.7 20.8 22.9 25.0
120000 3.5 7.0 10.5 14.0 17.5 21.0 24.5 28.8 31.5 35.0 — —
90000 .6 1.2 1.9 2.5 3.1 3.7 4.3 5.0 5.6 6.2 6.8 7.4
5/8"
120000 1.1 2.1 3.2 4.2 5.3 6.4 7.4 8.5 9.5 10.6 11.7 12.7
Note 1: A blank space indicates a pressure drop of more than 35 PSI.
Note 2: Other existing sources of pressure drop such as solenoid valves, etc. must be accounted for.
Note 3: A vertical run with a heat pump system always results in a liquid lift (heating or cooling).
Note 4: The smallest liquid line diameter that results in a total liquid line pressure drop of 35 PSI or less results in the most reliable system (fewer pounds of R-22).

Selecting A Liquid Line, Using Table “A”

Step #1 Subtract .5 PSI per foot of liquid lift (if any) from the 35 PSI liquid line pressure drop which can be tolerated by U.P.G. sys-
tems (R-22).
Step #2 Calculate the equivalent length of the liquid line (linear length plus an allowance for elbows, etc.). See Table “C,” page 10,
for equivalent lengths of elbows, etc.
Step #3 Select a liquid line from Table “A” which can handle the system BTUH at the calculated equivalent length within the
available pressure drop found in Step #1. (Your first try would normally be the rated liquid line size for the system.)
Example
Given: Rated system capacity = 42000 BTUH, 68 linear ft., 4 long radius elbows (no solenoid valve or other source of pressure
drop): 20 ft. liquid lift.
Step #1 20 x .5 = 10 PSI pressure drop due to liquid lift. 35 PSI (available) minus 10 PSI = 25 PSI available for friction loss.
Step #2 68 + (4 x 3.2) = 80.8 eq. ft. (See Table “C,” page 10, for equivalent lengths.)
Step #3 Referring to Table “A” we find: A – 42000 BTUH with 5/16" O.D. tubing @ 80 eq. ft. = 29.3 PSI (too high)
B – 42000 BTUH with 3/8" O.D. tubing @ 80 eq. ft. = 10.2 PSI (O.K.)

32-3009-03 7
 Application
Guide

Suction Lines for do not. These compressors are provided improper mixing of hot gas and
with special piping which allows oil lev- desuperheating liquid may result
Split Cooling and els in the two compressors to equalize.) in slugging of liquid refrigerant.
Heat Pump Systems
Do not use evaporator pressure regulat- Do not tape or otherwise fasten liquid
Suction lines must return refrigerant lines and suction lines together unless
ing valves (EPR valves) or similar throt-
vapor and oil from the evaporator to there is insulation between them. The
tling valves in the suction line. Hermetic
the compressor during operation of the resultant heat exchange would increase
compressors depend on suction gases
system, but should not allow oil or liquid suction gas superheat and may cause
for cooling and as the EPR valve throttles
refrigerant to be returned as slugs at any overheating of the hermetic compressor.
time, because of the danger of broken down to maintain a constant evaporator
pressure, the quantity of suction gas (See Tubing Hints on page 13.)
compressor valves, oil dilution, etc.
returning to the compressor is reduced
and its superheat is increased. The only Suction lines must be insulated to pre-
Never attempt to operate two hermetic vent condensation and vapor sealed
compressors with a common suction type of capacity modulation recom-
mended (other than multiple units) is a on the outside to prevent a build-up
line. It is impossible to return oil to each of moisture in the insulation.
compressor at precisely the same rate hot gas by-pass system properly applied
as it is being pumped. As a result, one so as to keep suction gas superheat It is advisable to avoid running
compressor will eventually run low on within normal limits, and provide proper refrigerant lines underground
oil in its sump and proper lubrication velocity through the evaporator and whenever possible. If it is absolutely
is no longer possible. Each hermetic suction lifts (if any) for adequate oil necessary to run refrigerant lines under-
compressor must have its own separate return. ground, they must be run in 6" P.V.C.
refrigerant system. conduit. (See Figure 1 below.)
High superheat will result in improper
(Our two compressor systems may cooling of the hermetic compressor,
appear to violate this rule, but they while excessively low superheat or

Figure 1
Underground Conduit
(For Underground Refrigerant Lines)

Both Ends Sealed Water Tight

45° Ells

No Joints In Copper
6" PVC Pipe Schedule 40 Within The Conduit

Use 45° elbows to facilitate pulling the conduit is critical. Some installers install
tubing through the conduit. The purpose a drain in the lower parts of the conduit.
of the conduit is to keep water away Bear in mind, that if the water table rises
from the refrigerant lines. Careful seal- above the drain, water may be forced
ing, where the lines enter and leave the into the conduit.

8 32-3009-03
 Application
Guide

About Suction Lines 3 – Increase the indoor airflow some- the compressor is equipped with sump
what, within the 350 to 450 CFM per ton heat, in order to bring the system up to
and Pressure Drops limits. (Some latent capacity will be lost.) current requirements.)
ASHRAE recommends that suction line 4 – Select a different equipment
pressure drop be limited to a pressure combination that provides the The Dilemma:
corresponding to 2°F (approx. 3.0 PSI needed capacity. Suppose that a service man is attempt-
with R-22). This is usually not a problem
ing to check the refrigerant charge in
with line sets of 100 eq. ft. or less. The pressure drop values show in Table the existing 2-1/2 ton system, with 5/16"
“B” are not required in order to select a – 5/8" O.D. refrigerant lines, mentioned
A quick look at the pressure drop per suction line. They are provided for your
100 ft. listed in Table “B” reveals that above (F.C.C.V. flow control). He is using
information only. One example of their the superheat method and, based on the
using the largest allowable suction line use might be to evaluate an existing
diameter for each tonnage results in a existing indoor and outdoor conditions,
system. For instance, careful measure- has determined that 10° superheat, at
pressure drop of less than 3 PSI per ments of an existing 2-1/2 ton system,
100 eq. ft. in all cases, except the 1 ton the outdoor unit is required.
installed with a 5/16" liquid line and
system (3.3 PSI). 5/8" suction reveal the following: 110 His compound gauge indicates 63 PSIG
linear ft., 8 short radius elbows. The or 36° evaporating temperature. Adding
Obviously, if line sets exceed 100 eq. ft. equivalent length, 110 + (8 x 5.7*)
significantly, there will be cases where 10° to the 36° tells him that he should
= 155.6 ft. (*from Table “C” page 10). try for a 46° suction line temperature,
the suction line pressure drop exceeds 155.6 ft. x 12.7/100 = approx. 19.8 PSI
3.0 PSI. (This is a price we must pay for right? Wrong in this case!
suction line pressure drop (more than six
long line sets.) times the ASHRAE recommendation). His actual evaporating pressure is
In those cases, where long tubing 63 PSIG plus 19.8 PSI pressure drop,
The approx. 20% loss in capacity tells or approx. 83 PSIG (49° plus.) The
runs result in higher suction line us that our 2-1/2 ton system is delivering
pressure drops than desired, do not desired suction line temperature = 59°.
2 tons. This 20% loss in capacity, to- Attempting to charge to the 46° suction
use a suction line diameter larger than gether with a 10% loss in efficiency,
those listed in Table “B,” page 10, line temperature would undoubtedly
makes a very strong case for replacing result in a severe overcharge. The
for the system tonnage. To do so the line set with a properly sized line set.
would result in refrigerant velocities extreme pressure drop not only resulted
too low to ensure oil return. in very substantial losses in capacity and
Assuming that the 5/8" O.D. suction efficiency, but could easily be the cause
line is to be replaced with a 7/8" O.D. of a severe overcharge (and possibly a
The net capacities indicated in Table “B” suction line, and the installer was able
for the various equivalent lengths show compressor failure).
to reduce the number of elbows to six
that there is approx. 1% loss in capacity (long radius) elbows: the equivalent
for each 1.0 PSI of pressure drop. (Effi- Always select one of the suction line
length = 110 + (6 x 5.3) or 141.8 ft., sizes listed in Table “B” for the nominal
ciency losses are approx. .5% per PSI 2.0 PSI/100 ft. (from Table “B”) x
of pressure drop.) tonnage of your system. Oil return will
141.8/100 = approx. 2.8 PSI suction line be assured with any of the listed sizes.
pressure drop. The lowest possible capacity losses
If the net capacity, indicated for the
calculated equivalent length, falls a consistent with adequate oil return are
The 30000 BTUH system will now deliver afforded by the largest tube size listed.
little short of your requirement (and approx. 29500 BTUH (140 eq. ft. value).
you have selected the largest allowable Short tubing runs may provide accept-
The loss in efficiency is now less than able losses with a smaller tube size.
tube diameter) one of the following 1%, which will be reflected in the
hints may remedy the situation: Net capacities are listed for all approved
owner’s electric bill (favorably). sizes for equivalent lengths up to 240 ft.
1 – Move the outdoor unit closer,
if possible. (The installer, when replacing the
2 – Use as few elbows as possible, and undersized refrigerant lines, should
use long radius elbows to reduce the convert the indoor unit to expansion
equivalent length. valve flow control and make sure that

32-3009-03 9
 Application
Guide

Table “B”
Allowable Suction Line Diameters and Net Capacities
Tube Nominal P.D. Net Capacity For Equivalent Length
Nom. Size Capacity Per
Tons (In.) (25 Ft.) 100 Ft. 40 60 80 100 120 140 160 180 200 220 240
1.0 1/2 14685 11.7 14425 14080 13735 13390 13045 — — — — — —
5/8 15000 3.3 14925 14825 14725 14625 14525 14425 14325 14225 14125 14025 13925
1.5 5/8 18000 4.7 17875 17705 17535 17365 17195 17025 16855 16685 16515 16345 16175
3/4 19305 1.8 19255 19185 19115 19045 18975 18905 18835 18765 18695 18625 18555
5/8 23695 8.1 23405 23020 22635 22250 21865 21480 21095 20710 — — —
2.0 3/4 24000 3.0 23890 23745 23600 23455 23310 23165 23020 22875 22730 22585 22440
7/8 24100 1.3 24055 23990 23925 23860 23795 23730 23665 23600 23535 23470 23405
5/8 29370 12.7 28810 28665 27320 26575 25830 — — — — — —
2.5 3/4 30000 4.6 29795 29520 29245 28970 28695 28420 28145 27870 27595 27320 27045
7/8 30195 2.0 30105 29985 29865 29745 29625 29505 29385 29265 29145 29025 28905
3.0 3/4 35670 6.5 35320 34855 34390 33925 33460 32995 32530 32065 31600 31135 30670
7/8 36000 2.8 35850 35650 35456 35250 35050 34850 34650 34450 34250 34050 33850
3/4 41475 8.8 40930 40200 39470 38740 38010 37280 36550 35820 — — —
3.5 7/8 42000 3.8 41760 41440 41120 40800 40480 40160 39840 39520 39200 38880 38560
1-1/8 42295 1.0 42230 42145 42060 41975 41890 41805 41720 41635 41550 41465 41380
4.0 7/8 47570 4.9 47220 46755 46290 45825 45360 44895 44430 43965 43500 43035 42570
1-1/8 48000 1.3 47905 47780 47655 47530 47405 47280 47155 47030 46905 46780 46655
7/8 59175 7.5 58510 57620 56730 55840 54950 54060 53170 52280 51390 — —
5.0 1-1/8 60000 2.0 59820 59580 59340 59100 58860 58620 58380 58140 57900 57660 57420
1-3/8 60195 .7 60130 60045 59960 59875 59790 59705 59620 59535 59450 59365 59280
6.0 1-1/8 72000 2.8 71700 71295 70890 70485 70080 69675 69270 68865 68460 68055 67650
1-3/8 72325 1.0 72215 72070 71925 71780 71635 71490 71345 71200 71055 70910 70765
1-1/8 89390 4.2 88825 88075 87325 86575 85825 85075 84325 83575 82825 82075 81325
7.5 1-3/8 90000 1.5 89795 89525 89255 88985 88715 88445 88175 87905 87635 87365 87095
1-5/8 90205 .6 90125 90015 89905 89795 89685 89575 89465 89355 89245 89135 89025
1-1/8 118560 7.4 117245 115490 113785 111980 110225 108470 106715 104960 103205 101450 —
10.0 1-3/8 120000 2.6 119230 118905 118280 117655 117030 116405 115780 115135 114530 113905 113280
1-5/8 120450 1.1 120250 119985 119720 119455 119190 118925 118660 118395 118130 117865 117600
Note 1: Shaded values = more than 10% capacity loss.
Note 2: Blank space = more than 15% capacity loss.

Suction Line Selection Example

Given:␣ 4 ton system fall between 140 and 160 ft., common line size for a 4 ton system.) The equiva-
132 linear ft. sense tells us that we should select the lent length, 132 + (8 x 1.9) = 147.2 ft. The
largest diameter tube listed for a 4 ton net capacity will be between 47280 and
8 long radius elbows
system in Table “B,” which is 1-1/8" O.D. 47155 BTUH (47235 BTUH, by interpola-
Since the equivalent length will probably (This happens to be the rated suction tion). This translates to a capacity loss
of approx. 1.6%. (good)
Table “C” Question
Equivalent Length (Ft.) of Non-Ferrous Valves and Fittings (Brazed) Would a 7/8" O.D. suction line be ad-
equate for a 4 ton system with a piping
O.D. Short Long Tee run of 60 equivalent feet?
Tube Size Globe Angle Radius Radius Tee Branch
(Inches) Valve Valve Ell Ell Line Flow Flow Answer
1/2* 70 24 4.7 3.2 1.7 6.6
Obviously, oil return would not be a
5/8 72 25 5.7 3.9 2.3 8.2 problem with the smaller diameter tube,
3/4 75 25 6.5 4.5 2.9 9.7 (higher velocity). So, if the capacity loss
7/8 78 28 7.8 5.3 3.7 12.0 of approx. 2.5% is not a problem, the
1-1/8 87 29 2.7 1.9 2.5 8.0 7/8" O.D. suction line is O.K. in this case.
1-3/8 102 33 3.2 2.2 2.7 10.0
1-5/8 115 34 3.8 2.6 3.0 12.0 ( 48000 – 46755 = approx. 2.5%)
48000
Information for this chart extracted by permission from A.R.I. Refrigerant Piping Data, page 28.
* For smaller sizes, use 1/2" values.

10 32-3009-03
 Application
Guide

Piping Limits
1. Compressor Protection
A. Suction line accumulators are no longer required (on 1 through 10 ton systems).
B. Protect reciprocating compressors as follows:
• Up to 80 linear feet of rated tube sizes: OK as shipped.
• Over 80 linear feet , or oversized lines: Apply sump heat1 and TXV indoor metering device.13
C. Protect Scroll compressors as follows:
• Up to 12 lbs. R-22 system charge2: OK as shipped.
• 10.5 lbs. for R-410A.
• Over 12 lbs. R-22 system charge2: Apply sump heat and TXV indoor metering device.1
D. Liquid line solenoid valves (straight cooling systems only):*
Cycle solenoid valve with compressor (no pump down).
• If compressor is above the indoor unit, locate the liquid line solenoid valve near the indoor unit.
• If compressor is below the indoor unit, locate the liquid line solenoid valve within 25 ft. of compressor.
Note: If pump down is desired, a discharge check valve must be installed in the discharge line. (Locate the liquid line solenoid valve near the indoor unit.)
* Liquid line solenoid valves are not required with TXV systems.

2. Piping Limitations (Heat Pumps and Straight Cooling)

A. Suction line diameter must be one of those listed in Table “B,” based on system tonnage.
B. Maximum linear length = 200 ft.
C. Maximum linear liquid lift = 60 ft. (except high rise systems with liquid subcooler).
D. Maximum linear suction lift = 200 ft.
E. If it is necessary to exceed the above limits, contact Application Engineering.
F. Note special limitations for two compressor systems and R-410A systems below.

3. High Rise Systems

A. The high rise system, with liquid subcooler, is limited to heat pump systems only, with the outdoor unit
above the indoor unit.
B. The indoor unit on high rise applications must utilize a TXV metering device.

4. 3, 4 and 5 Ton Manifolded Compressor Systems Tube Sizes

A. Maximum linear length = 80 ft. 3 Ton = 3/8" and 7/8"
B. Maximum lift (suction or liquid) = 25 ft. 4 and 5 Ton = 3/8" and 1-1/8"

5. R-410A Systems
A. Maximum linear length = 200 ft.
B. Maximum linear liquid lift = 60 ft.
C. Maximum linear suction lift = 200 ft.

6. Traps
A. Traps are not recommended.

Notes:
1 If not factory furnished.
2 System charge = nameplate charge, plus tubing allowance (See page 12 for Tubing Allowance).
3 If a non-bleed TXV is applied to a single phase Reciprocating compressor system, a hard start kit will be required (not required with Scroll compressor systems).
4 Pub. No. 32-3312-01 (Windows® based) computer software contains complete piping data, including high rise systems, R-410A, pressure drops, net capacity,
system charge, tube sizes, etc.

32-3009-03 11
 Application
Guide

Table “E-1” Note: Hard Start Kits are required for

single phase systems with non-bleed
Refrigerant Piping and Accessories for Trane and TXV. (Reciprocating Compressors Only.)
American Standard Reciprocating and
Scroll Compressors
Table “E-2”
Thermal Expansion Valve
B Tubing Allowance (Lbs. R-22) Conversion
for Cooling Units (TXV)
Ounces Pounds
Tube Size
1.00 0.0625 Bleed Non-Bleed
(Inches) 40' 60' 80' 100' 120' 140' 160' 180' 200'
2.00 0.1250 Unit Tonnage Type Valve Type Valve
1/4 – 5/8 0.4 0.7 1.1 1.4 1.7 2.1 2.4 2.7 3.1
3.00 0.1875 1 – 1-1/2 TAYTXVA0B5C TAYTXVA0B3C
5/16 – 3/4 0.7 1.3 1.8 2.4 3.0 3.5 4.1 4.7 5.2 4.00 0.2500 2 – 2-1/2 TAYTXVA0C5C TAYTXVA0C3C
5/16 – 7/8 0.7 1.3 1.9 2.5 3.1 3.7 4.3 4.9 5.5 5.00 0.3125
3 – 3-1/2 TAYTXVA0E5C TAYTXVA0E3C
5/16 – 1-1/8 0.8 1.5 2.2 2.9 3.5 4.2 4.9 5.6 6.2 6.00 0.3750
4 TAYTXVA0G5C TAYTXVA0G3C
3/8 – 3/4 1.1 1.9 2.8 3.6 4.5 5.3 6.2 7.0 7.9 7.00 0.4375
8.00 0.5000 5–6 TAYTXVA0H5C TAYTXVA0H3C
3/8 – 7/8 1.1 2.0 2.9 3.8 4.6 5.5 6.4 7.3 8.2
9.00 0.5625 Note: TXV’s are Brazed Type Connections.
3/8 – 1-1/8 1.2 2.2 3.1 4.1 5.1 6.0 7.0 7.9 8.9
10.00 0.6250
3/8 – 1-3/8 1.3 2.3 3.4 4.3 5.4 6.4 7.4 8.4 9.5
11.00 0.6875
Table “E-2”
1/2 – 1-1/8 2.0 3.6 5.2 6.9 8.5 10.1 11.7 13.3 14.9
12.00 0.7500
1/2 – 1-3/8 2.1 3.9 5.6 7.3 9.0 10.7 12.4 14.1 15.8 13.00 0.8125
Thermal Expansion Valve
1/2 – 1-5/8 2.3 4.1 6.0 7.8 9.6 11.5 13.3 15.1 17.0 14.00 0.8750 for Heat Pump Units (TXV)
5/8 – 1-3/8 3.1 5.6 8.1 10.6 13.1 15.6 18.1 20.6 23.1 15.00 0.9375 Unit Tonnage Non-Bleed Type Valve
5/8 – 1-5/8 3.4 6.1 8.8 11.5 14.3 17.0 19.7 22.4 25.1 16.00 1.0000
1 – 1-1/2 TAYTXVH0B3C
2 – 2-1/2 TAYTXVH0C3C
Reciprocating Compressors
3 – 3-1/2 TAYTXVH0E3C
Up to 80 linear ft. of rated tubing size Over 80 linear ft. or oversized tubing
4 TAYTXVH0G3C
O.K. as shipped Required: Sump Heat2, Indoor TXV23 5–6 TAYTXVH0H3C
Note: TXV’s are Brazed Type Connections.
Scroll Compressors
Sump Heater Kit
C Up to 12 lbs.* system charge1 C Over 12 lbs.* system charge1
Reciprocating Compressors
O.K. as shipped Required: Sump Heat2, Indoor TXV23
BAYCCHT003AA
1 Nameplate charge (indoor unit, outdoor unit + 15 ft. tubing) plus tubing allowance (over 15 ft.).
2 Add, if not factory furnished. One Size Fits All
3 Bleed or Non-Bleed.
* 10.5 lbs. for R-410A systems Sump Heater Kits for
Note: Failure to add the required components (systems over 12 lbs.) may result in noise
complaints and/or compressor damage. Use actual measured length. The 15 ft. is accounted for. Scroll Compressors
Thermal jackets are no longer required.
A + B = C BAYCCHT200A BAYCCHT201A
NAMEPLATE CHARGE TUBING ALLOWANCE SYSTEM CHARGE*
(15 Ft. Tubing Included) Used with compressors Used with compressors
*Always check refrigerant charge when starting system, as recommended in installer’s guide.
SSR or SPR SSR or SPR
Note 1: Refer to unit nameplate, or product specifications page in Product Data Catalog or 024 through 045 and 047 048 through 077 and 046
Service Facts for nameplate charge.
Refer to optional equipment listing for heater part number or
Note 2: Two compressor systems are limited to 80 linear feet and 25 feet linear lifts, suction or liquid. refer to product specifications for compressor type and select
Note 3: If nameplate charge is given in pounds and ounces, refer to conversion table above. from above table.

Application Requirements Liquid lifts up to 60 linear ft. Suction line accumulator is not required
Systems within the limits indicated Suction lifts up to 200 linear ft. on 1 through 10 tons.
above, or systems beyond those limits
This includes R-410A systems (recom- Do not apply pump down cycle, unless
which are equipped with compressor
mended line sizes only), but does not discharge check valve has been applied.
sump heat and indoor TXV refrigerant
include two compressor systems which (See page 11.)
control, are O.K. for:
are limited to 80 linear ft. and to lifts
Linear Lengths up to 200 ft.
(liquid or suction) of up to 25 linear ft.

12 32-3009-03
 Application
Guide

Figure 3 Figure 2
Thermal Bulb Location Typical Straight Cooling System
(Outdoor Unit Above Indoor Unit)

LIQUID LINE

SUCTION LINE Maximum Suction Lift = 200 Ft.

(Solenoid valve near expansion valve.)
Solenoid Valve (If used)
– Cycle with compressor or,
– Apply discharge check valve and
utilize pump down cycle.
SUCTION LINE
Note: If compressor is below the indoor unit, install the
7/8" DIAMETER solenoid valve within 25 ft. of the compressor, and cycle
OR SMALLER with the compressor, only. (No pump down.)
Maximum Liquid Lift = 60 ft.
OR,
– Apply discharge check valve.
– Locate solenoid valve near indoor unit.
– Utilize pump down cycle.

TXV LIQUID LINE SOLENOID VALVE*

* Solenoid valves not required with TXV systems.

Figure 4
Tubing Hints

SUCTION LINE
LARGER THAN 7/8"

STRAP HANGER

ADJUSTABLE ROD HANGER

SADDLE
SADDLE SUPPORT

Copyright by ASHRAE. Reprinted by Permission from

ASHRAE Guide & DAta Book, System 1970, page 356.
YES YES NO

32-3009-03 13
 Figure 5

Basic Air Conditioning Formulas

EXPRESSED
TO DETERMINE AS
Application NT V
COOLING HEATING and/or HUMIDIFYING
NT V
Total Airflow CFMT 1. CFMT = 1. CFMT =
Guide 60 min./hr. 60 min./hr.

NO V No V
Infiltration or Ventilation CFMo 2. CFMo = 2. CFMo =
60 min./hr. 60 min./hr.

Number of Air Changes CFMT (60 min./hr.) CFMT (60 min./hr.)

NT 3. NT = 3. NT =
Per Hour – Total V V

Number of Air Changes CFMo (60 min./hr.) CFMo (60 min./hr.)

Per Hour – Outdoor Air No 4. No = 4. No =
V V

Total Heat (HT) Btuh 5. HT = CFMT x 4.5 x (h1 – h2) = Btuh 6. HT = CFMT x 4.5 x (h2 – h1) = Btuh

Sensible Heat (HS) Btuh 7. HS = CFMT x 1.08 x (T1 – T2) = Btuh 8. HS = CFMT x 1.08 x (T2 – T1) = Btuh

Latent Heat (HL) Btuh 9. HL = CFMT x .68 x (W1 – W2) = Btuh 10. HL = CFMT x .68 x (W2 – W1) = Btuh

CFMo CFMo
Entering Air Temperature (T1) °F. D.B. 11. T1 = t1 + x (t2 – t1) = °F.D.B. 1 12. T1 = t1 – x (t1 – t2) = °F.D.B. 2
CFMT CFMT
(Mixed Air)
1 If duct heat gain is a factor, add to T1: 2 If duct heat loss is a factor, subtract from T1:
Duct Heat Gain (Btuh) Duct Heat Loss (Btuh)
CFMT x 1.08 CFMT x 1.08

Leaving Air D.B. HS HS

°F. D.B. 13. T2 = T1 – = °F.D.B. 14. T2 = T1 + = °F.D.B.
Temperature (T2) CFMT x 1.08 CFMT x 1.08
HS (total) HS
Required Airflow CFMT 15. CFMT = = CFM 16. CFMT = = CFM
1.08 x (T1 – T2) 1.08 x (T2 – T1)
OR
HS (internal)3
CFMT = = CFM
1.08 x (t1 – T2)
3 Sensible load of outside air not included

Btu/lb. HT HT
Enthalpy – Leaving Air (h2) 17. h2 = h1 – = Btu/lb. dry air 18. h2 = h1 + = Btu/lb. dry air
dry air CFMT x 4.5 CFMT x 4.5

19. Refer to Enthalpy Table and read W.B. temperature 20. Refer to Enthalpy Table and read W.B. temperature
Leaving Air W.B. Temperature °F.W.B.
corresponding to enthalpy of leaving air (h2) (see #17). corresponding to enthalpy of leaving air (h2) (see #18).
Heat Required to Evaporate
Water Vapor Added to Btuh 21. HL = CFMo x .68 (W3 – Wo) = Btuh 22. HL = CFMo x .68 (W3 – Wo) = Btuh
Ventilation Air
Excess Latent Capacity
HL loss Btuh (see #22)
Humidification Requirements
Lbs.
water/hr.
23.
( Moisture )
Make up = of System x % Run Time
1060 Btu/lb.
= lbs./hr.
(
24. Make up =
Moisture ) 1060 Btu/lb.
= lbs./hr.

(Industrial Process Work)

LEGEND DERIVATION OF AIR CONSTANTS

CFMT = Total airflow cubic feet/min. The air constants below apply specifically to standard air which is
CFMo = Outdoor air cubic feet/min. defined as dry air at 70°F and 14.7 P.S.I.A. (29.92 in. mercury column).
NT = Total air changes per hour They can, however, be used in most cooling calculations unless extremely
No = Outdoor air, air changes per hour precise results are desired.
V = Volume of space cubic feet 4.5 (To convert CFM to lbs./hr.)
HT = Total heat Btuh
HS = Sensible heat Btuh 60 min./hr.
4.5 = or 60 X .075
HL = Latent heat Btuh 13.33
* h1 = Enthalpy or total heat of entering air Btu/lb. Where 13.33 is the specific volume of standard air (cu.ft./lb.) and
* h2 = Enthalpy or total heat of leaving air Btu/lb. .075 is the density (lbs./cu.ft.)
T1 = Temperature of entering air .24 X 60
T2 = Temperature of leaving air 1.08 = or .24 X 4.5
13.33
Tadp = Apparatus dewpoint °F.D.B.
.24 BTU = specific heat of standard air (BTU/LB/°F)
t1 = Indoor design temperature °F.D.B.
t2 = Outdoor design temperature °F.D.B. .68 =
60
X
1060
or 4.5 X
1060
W1 = Grains of water/lb. of dry air at entering condition Grains/lb. 13.33 7000 7000
W2 = Grains of water/lb. of dry air at leaving condition Grains/lb.
Where: 1060 = Average Latent Heat of water vapor (BTU/LB.).
W3 = Grains of water/lb. of dry air at indoor design conditions Grains/lb.
Wo = Grains of water/lb. of dry air at outdoor design conditions Grains/lb. 7000 = Grains per lb.

* See Enthalpy of air (Total Heat Content of Air) Table for exact values.

14 32-3009-03
 Application
Guide

R-410A Refrigerant POE oils absorb moisture very quickly. Figure 6

Keep container tightly closed, whenever
R-410A is a near-azeotropic mixture of possible, and expose the system to the
R-32 and R-125 refrigerants. Some sepa- R-410A Temperature and
atmosphere as little as possible. POE
ration of the two components can occur Pressure Chart
oils can also damage a roof, if spilled.
in the vapor phase (not enough to cause TEMP. R-410A TEMP. R-410A TEMP. R-410A
a significant change in the composition Vacuum pumps can not remove all of -60 1.2 16 71.7 44 127.3
of the refrigerant with a refrigerant leak). the moisture from POE oils. Change the -55 3.4 17 73.3 45 129.7
However, it is recommended that charg- liquid line drier anytime the system is -50 5.8 18 75.0 46 132.2
ing be done in the liquid phase. When opened to the atmosphere. -45 8.6 19 76.6 47 134.6
adding liquid refrigerant into the low -40 11.6 20 78.3 48 137.1
Suction line dryers are to be left in -35 14.9 21 80.2 49 139.6
side of the system, a charge metering
the system for no more than 72 hours. -30 18.5 22 81.8 50 142.2
device is recommended (WATSCO -25 22.5 23 83.6 55 155.5
Use only liquid and suction line dryers
CH200, or equivalent). Allow ample -20 26.9 24 85.4 60 169.6
approved for R-410A.
time when adding refrigerant, for the -15 31.7 25 87.3 65 184.6
system to balance out, to avoid having -10 36.8 26 89.1 70 200.6
Since all current R-410A systems
-5 42.5 27 91.0 75 217.4
to recover refrigerant. are expansion valve systems, the 0 48.6 28 92.9 80 235.3
refrigerant charge is to be checked 1 49.9 29 94.9 85 254.1
R-410A cylinders are pink in color and
by the subcooling method. 2 51.2 30 96.8 90 274.1
dispense liquid when in the upright 3 52.5 31 98.8 95 295.1
position. (This may change.) Maximum liquid line pressure drop 4 53.8 32 100.8 100 317.2
with R-410A systems is 50 PSI (10° 5 55.2 33 102.9 105 340.5
Gauges, hoses, recovery cylinders, 6 56.6 34 105.0 110 365.0
subcooling). Recommended suction
and recovery machines must handle 7 58.0 35 107.1 115 390.7
line pressure drop (2°F) is 4.8 PSI
the higher pressures associated with 8 59.4 36 109.2 120 417.7
(Round up to 5.0). 9 60.9 37 111.4 125 445.9
R-410A. (See pressure/temperature
10 62.3 38 113.6 130 475.6
chart.) Note that 45° corresponds to At this time, only matched systems 11 63.8 39 115.8 135 506.5
129.7 PSIG, and 115° corresponds to are permitted with R-410A. 12 65.4 40 118.0 140 539.0
390.7 PSIG (compared to 76.0 PSIG 13 66.9 41 120.3 145 572.8
and 242.7 PSIG for R-22). R-410A boils at –62.9° at atmospheric 14 68.5 42 122.6 150 608.1
pressure, so be wary of frostbite! 15 70.0 43 125.0 155 645.0
R-410A has practically no temperature
“Glide.” (The temperature remains
practically constant when going from
100% liquid to a saturated vapor at
a given pressure.) Table “G”
Existing Halide leak detectors do not Pounds of R-410A Required for Line Sets
work with R-410A. Existing acid test kits
TUBING Linear Length
do not work with R-410A. (New kits are
SIZES 40 60 80 100 120 140 160 180 200
being developed.) Note that although
1/4" – 5/8" .4 .7 1.0 1.4 1.7 2.0 2.3 2.6 3.0
R-410A does not deplete the ozone layer,
5/16" – 3/4" .7 1.2 1.8 2.3 2.8 3.4 3.9 4.5 5.0
all refrigerants must be recovered. 5/16" – 7/8" .7 1.3 1.9 2.5 3.0 3.6 4.2 4.8 5.4
5/16" – 1-1/8" .9 1.5 2.2 2.9 3.6 4.3 4.9 5.6 6.3
Do not expose R-410A cylinders to
3/8" – 3/4" 1.0 1.7 2.5 3.2 4.0 4.8 5.5 6.3 7.0
temperatures over 125°F. 3/8" – 7/8" 1.0 1.8 2.6 3.4 4.2 5.0 5.8 6.6 7.4
R-410A systems use a POE oil, which 3/8" – 1-1/8" 1.1 2.0 2.9 3.8 4.7 5.6 6.5 7.4 8.3
3/8" – 1-3/8" 1.3 2.3 3.4 4.4 5.5 6.5 7.5 8.6 9.6
is not compatible with the oils used in
1/2" – 7/8" 1.7 3.1 4.4 5.8 7.1 8.5 9.9 11.2 12.6
R-22 systems. If existing refrigerant lines 1/2" – 1-1/8" 1.8 3.3 4.7 6.2 7.7 9.1 10.6 12.0 13.5
are to be used with and R-410A system 1/2" – 1-3/8" 2.0 3.6 5.2 6.8 8.4 10.0 11.6 13.2 14.8
(assuming that the line sizes are accept- 1/2" – 1-5/8" 2.2 4.0 5.7 7.5 9.2 11.0 12.8 14.5 16.3
able), they must be thoroughly blown 5/8" – 1-3/8" 3.0 5.4 7.7 10.1 12.5 14.9 17.3 19.6 22.0
out with dry nitrogen to remove the 5/8" – 1-5/8" 3.2 5.7 8.3 10.8 13.3 15.9 18.4 21.0 23.5
old oil. Blow vertical sections from top Note: The 15 ft. of tubing included in the nameplate charge has been accounted for, use actual linear length with
to bottom. the above table.

32-3009-03 15
 Application
Guide

Table “A-R (R-410A)”

Liquid Line Selection Table For R-410A Systems
Maximum Allowable Liquid Line Pressure Drop .................................................................................................. = 50 PSI
Subtract .43 PSI for each foot of Liquid Lift (if any) ....................................................................................................
Do Not Exceed this value when selecting Liquid Line. ...............................................................................................

Pressure Drop (PSI) For Total Equivalent Length

Tube Rated
O.D. BTUH 20' 40' 60' 80' 100' 120' 140' 160' 180' 200' 220' 240'
1/4" 15000 4.5 9.0 13.6 18.1 22.6 27.1 31.6 36.2 40.7 45.2 49.7 —
18000 6.3 12.6 18.8 25.1 31.4 37.7 44.0 — — — — —
15000 1.2 2.4 3.5 4.7 5.9 7.1 8.3 9.4 10.6 11.8 13.0 14.2
18000 1.6 3.3 4.9 6.6 8.2 9.8 11.5 13.1 14.8 16.4 18.0 19.7
5/16" 24000 2.8 5.5 8.3 11.0 13.8 16.6 19.3 22.1 24.8 27.6 30.4 33.1
30000 4.1 8.3 12.4 16.6 20.7 24.8 29.0 33.1 37.3 41.4 45.5 49.7
36000 5.8 11.6 17.3 23.1 28.9 34.7 40.5 46.2 — — — —
42000 7.7 15.4 23.0 30.7 38.4 46.1 — — — — — —
24000 1.0 1.9 2.9 3.8 4.8 5.8 6.7 7.7 8.6 9.6 10.6 11.5
30000 1.4 2.9 4.3 5.8 7.2 8.6 10.1 11.5 13.0 14.4 15.8 17.3
3/8" 36000 2.0 4.0 6.1 8.1 10.1 12.1 14.1 16.2 18.2 20.2 22.2 24.2
42000 2.7 5.3 8.0 10.6 13.3 16.0 18.6 21.3 23.9 26.6 29.3 31.9
48000 3.4 6.8 10.2 13.6 17.0 20.4 23.8 27.2 30.6 34.0 37.4 40.8
60000 5.1 10.3 15.4 20.6 25.7 30.8 36.0 41.1 46.3 — — —
42000 .5 1.1 1.6 2.2 2.7 3.2 3.8 4.3 4.9 5.4 5.9 6.5
48000 .7 1.4 2.0 2.7 3.4 4.1 4.8 5.4 6.1 6.8 7.5 8.2
1/2" 60000 1.0 2.1 3.1 4.2 5.2 6.2 7.3 8.3 9.4 10.4 11.4 12.5
72000 1.4 2.9 4.3 5.8 7.2 8.6 10.1 11.5 13.0 14.4 15.8 17.3
90000 2.2 4.3 6.5 8.6 10.8 13.0 15.1 17.3 19.4 21.6 23.8 25.9
120000 3.7 7.4 11.0 14.7 18.4 22.1 25.8 29.4 33.1 36.8 40.5 44.2
72000 .4 .9 1.3 1.8 2.2 2.6 3.1 3.5 4.0 4.4 4.8 5.3
5/8" 90000 .7 1.3 2.0 2.6 3.3 4.0 4.6 5.3 5.9 6.6 7.3 7.9
120000 1.1 2.2 3.3 4.4 5.5 6.6 7.7 8.8 9.9 11.0 12.1 13.2
Note 1: A blank space indicates a pressure drop of over 50 PSI.
Note 2: Other existing sources of pressure drop, (solenoid valves, etc.) must be considered.
Note 3: A vertical run with a heat pump system always results in a liquid lift (heating or cooling).
Note 4: The smallest liquid line diameter that results in a total liquid line pressure drop of 50 PSI or less results in the most reliable system (fewer pounds of R-410A).

Example
Given: Rated system capacity = 42000 BTUH, 68 linear ft., 4 long radius elbows (no solenoid valve or other source of
pressure drop): 20 ft. liquid lift.
Step #1 20 x .43 = 8.6 PSI pressure drop due to liquid lift. 50 minus 8.6 = 41.4 PSI available for friction loss.
Step #2 68 + (4 x 3.2) = 80.8 eq. ft. (See Table “C,” page 10, for equivalent lengths.)
Step #3 Referring to Table A-R, we find that 80 ft. of 5/16" liquid line, (42,000 BTUH) = 30.7 PSI pressure drop.
(Well within our 41.4 PSI limit.)

16 32-3009-03
 Application
Guide

Table “B-R (R-410A Refrigerant)”

Allowable Suction Line Diameters and BTUH Loss (R-410A)
Nominal Tube O.D. Press. Drop BTUH Loss For Equivalent Length
Tons (Inches) PSI/100 Ft. 40' 60' 80' 100' 120' 140' 160' 180' 200' 220' 240'
1.0 1/2* 5.0 70 160 250 340 430 520 610 700 790 880 970
5/8 1.5 20 50 73 100 130 155 180 210 235 265 290
1/2* 10.8 173 410 640 875 1110 1340 1575 1810 2040 2275 2510
1.5 5/8 3.1 50 120 185 250 320 385 450 520 585 655 720
3/4 1.2 20 45 70 95 125 150 175 200 225 255 280
5/8* 5.4 115 270 430 585 740 895 1050 1205 1360 1515 1670
2.0 3/4 2.0 45 100 160 215 275 330 390 445 505 560 620
7/8 .9 20 45 70 95 125 150 175 200 225 255 280
5/8* 8.2 220 515 810 1110 1400 1695 1990 2290 2585 2880 3175
2.5 3/4 3.0 80 190 295 405 515 620 730 840 945 1055 1160
7/8 1.3 35 80 130 175 220 270 315 365 410 455 505
5/8 11.7 380 885 1390 1895 2400 2905 3410 3915 4425 4930 —
3.0 3/4* 4.3 140 325 510 700 880 1070 1255 1440 1625 1810 2000
7/8 1.9 60 145 225 310 390 470 555 635 720 800 880
3.5 3/4* 5.8 220 510 805 1095 1390 1680 1975 2265 2560 2850 3140
7/8 2.5 95 220 345 475 600 725 850 975 1105 1230 1355
3/4 7.4 320 745 1170 1600 2025 2450 2875 3305 3730 4155 4580
4.0 7/8* 3.2 140 325 510 690 875 1060 1245 1430 1615 1795 1980
1-1/8 .9 40 90 145 195 245 300 350 400 455 505 555
3/4 11.5 620 1450 2280 3105 3935 4760 5590 6415 7245 8073 8900
5.0 7/8* 4.9 265 615 970 1325 1675 2030 2380 2735 3080 3440 3795
1-1/8 1.3 70 165 255 350 445 540 630 725 820 915 1005
3/4 16.5 1070 2495 3920 5345 6770 8195 9625 — — — —
6.0 7/8 7.0 455 1060 1665 2270 2875 3480 4080 4685 5290 5895 6500
1-1/8 1.8 115 270 430 585 740 895 1050 1205 1360 1515 1670
7/8 10.8 875 2040 3210 4375 5540 6705 7875 9040 10203 11370 12540
7.5 1-1/8 2.8 225 530 830 1135 1435 1740 2040 2345 2645 2950 3250
1-3/8 1.0 80 190 300 405 515 620 730 835 945 1055 1160
7/8 19.3 2085 4865 7645 10420 13200 15980 — — — — —
10.0 1-1/8 4.9 530 1235 1940 2645 3350 4255 4765 5470 6175 6880 7585
1-3/8 1.7 185 430 675 920 1165 1410 1650 1895 2140 2385 2630
Note: *Rated tube size.
Note 1: Shaded value indicates more than 10% capacity loss.
Note 2: Blank space indicates more than 15% capacity loss.

Suction Line Selection Example (R-410A)

Given:␣ 4 ton system The equivalent length of the rated, equivalent feet (approx. 3%). If this loss
132 linear ft. (7/8" O.D.) suction line size = 132 + is acceptable, 7/8" O.D. is the correct size.
(8 x 5.3) or 174.4 ft. Table B-R indicates If capacity is critical, the 1-1/8" O.D.
8 long radius elbows
a capacity loss of 1430 BTUH for 180 suction line loss is less than 400 BTUH.

Table “C” Question

Would a 3/4" O.D. suction line be
Equivalent Length (Ft.) of Non-Ferrous Valves and Fittings (Brazed) adequate for a 4 ton system with a
piping run of 60 equivalent feet?
O.D. Short Long Tee
Tube Size Globe Angle Radius Radius Tee Branch Answer
(Inches) Valve Valve Ell Ell Line Flow Flow
Obviously, oil return would not be a
1/2* 70 24 4.7 3.2 1.7 6.6 problem with the smaller diameter tube,
5/8 72 25 5.7 3.9 2.3 8.2 (higher velocity). So, if the capacity loss
3/4 75 25 6.5 4.5 2.9 9.7 of 745 BTUH, (approx. 1.5%) is not a
7/8 78 28 7.8 5.3 3.7 12.0 problem, the 3/4" suction line is O.K.
1-1/8 87 29 2.7 1.9 2.5 8.0 for the 60 equivalent feet.
1-3/8 102 33 3.2 2.2 2.7 10.0
1-5/8 115 34 3.8 2.6 3.0 12.0
Information for this chart extracted by permission from A.R.I. Refrigerant Piping Data, page 28.
* For smaller sizes, use 1/2" values.

32-3009-03 17
 Application
Guide

CHAPTER II umes of vapor, as well as substantially heat exchange capacity to provide the
reducing the capacity of the metering required additional subcooling for
High Rise Heat Pump device because of the mixture of vapor systems up through 10 tons (and is
Applications and liquid it would be forced to handle. rated for both R-22 or R-410A).
(R-22 and R-410A) It is not unusual for high rise systems It should be noted that although the
The demand for greater vertical separa- to operate with total liquid line pressure heat exchanger used with the high rise
tion for the indoor and outdoor sections drops in excess of 100 PSI (R-22) with no system is designed as a suction to liquid
of heat pump systems, over the years, “flashing” (even higher with R-410A.) heat exchanger, it is not used in that
has lead to the development of the high manner. (Suction gas is not routed
rise system. Until this time, the maxi- As mentioned earlier, the (windows) through the heat exchanger.) Instead,
mum allowable liquid lift for R-22 sys- computer piping program will call for the normal liquid flow is through the
tems was approximately 60 ft. The 60 ft. the subcooler when ever it is required, suction side of the heat exchanger. A
lift resulted in a pressure drop (60 x .5) size the capillary tube and call for any small portion of the liquid is fed through
of 30 PSI, which left only 5 PSI of the other required accessories. The rest of the capillary tube to the other side of the
allowable 35 PSI for friction loss. Some- this chapter is designed to help the sys- heat exchanger where it is evaporated
what higher liquid lifts can be tolerated tem designer who does not have access to chill the liquid R-22 the required
with R-410A systems, because the to the computer program to apply the number of degrees. A 3/8" O.D. suction
allowable (total) liquid line pressure high rise system. line (insulated) is run from the heat
drop for R-410A systems is 50 PSI, also exchanger (located at the bottom of
The heat exchanger used with the high the liquid lift) to the common suction
the loss for each foot of liquid lift is .43
rise system (refrigeration research line of the outdoor unit (between the
PSI versus .50 PSI for R-22.
#H-100, or Heat-X 3/4 HP) has sufficient switch-over valve and the compressor).
However, when liquid lifts become high
enough to produce a total liquid line
pressure drop (lift + friction) of over
35 PSI with R-22 systems or 50 PSI with Table “D”
R-410A systems, the high rise system
with subcooler will be required. Subcooling Heat Exchangers
The high rise system is to be applied to
heat pump systems only, and only on
systems where the outdoor unit is above ➤
the indoor unit. The indoor unit must
utilize expansion valve flow control.

The high rise system consists of a

Shell Overall Suction Liquid
subcooler (heat exchanger), a capillary Catalog O.D. (B) Length (E) Line (C) Line (D) Weight
tube and associated tubing. The new Number H.P. (Inches) (Inches) (Inches) (Inches) (Pounds)
(Windows) computer program (Pub. No. H 33 1/4 & 1/3 1-1/4 8-5/8 3/8 1/4 .8
32-3312-01) will call for the subcooler, H 50 1/2 2 10 1/2 1/4 1.3
automatically, when the total liquid line H 75 3/4 2 12-1/8 5/8 1/4 1.7
pressure drop exceeds 35 PSI (R-22) H 100 1 2 13-1/8 5/8 3/8 1.9
or 50 PSI (R-410A). The program also
H 150 1-1/2 2 17-3/8 7/8 3/8 2.5
selects the proper capillary tube size
H 200 2 3 13-1/4 7/8 3/8 3.1
for the application.
H 300 3 3 15-1/4 1-1/8 3/8 3.8
The purpose of the subcooler is to pro- H 500 5 5 14-3/8 1-1/8 1/2 7.0
vide subcooling beyond the 10° typically H 750 7-1/2 5 15-5/8 1-5/8 5/8 9.0
provided by standard systems. This is H 1000 10 5 18-5/8 1-5/8 5/8 11.0
necessary in order to tolerate the higher
liquid line pressure drops resulting
from high liquid lifts (plus friction loss)
without “flashing” of liquid refrigerant
to vapor. This “flashing,” when it occurs,
chokes up the liquid line with large vol-

18 32-3009-03
 Application
Guide

The 3/8" O.D. suction line is teed into the Figure 7 (below) indicates the hook-up door units. Note that there are now three
top of a horizontal common suction line, for the heat exchanger and capillary connecting lines between the indoor and
or into the side of a vertical common tube. The heat exchanger is to be located outdoor units (liquid line, gas line and a
suction line, thus preventing the drain- at the bottom of the liquid lift (near the 3⁄8” insulated suction line) running from
age of oil down the 3/8" O.D. tube. indoor unit). the heat exchanger to the common suc-
Figure 8, page 20, shows the piping tion line (between the switchover valve
The fact that a small portion of the liquid hook-up between the indoor and out- and the compressor).
R-22, being circulated, is diverted to the
heat exchanger, and boiled to a vapor,
has no effect on system capacity. While a
slightly reduced quantity of liquid R-22 is
delivered to the system evaporator, each Figure 7
pound contains less heat, because of the
additional subcooling and the net cool- Piping Detail – Heat Exchanger
ing effect is the same. So what have we
accomplished? We have delivered 100%
liquid to the system expansion valve, in
spite of liquid line pressure drops of 100
PSI or more.
The heat exchanger and capillary tube
are to be purchased at your local parts
wholesaler.
Table “D,” page 18, provides a picture To liquid line
and dimensional information for the connection at
heat exchanger. outdoor unit Insulated 3/8" line.
Tee into common suction
Note that the heat pump indoor unit line, between S.O.V. and
Refrigeration Research H-100 or

must utilize expansion valve refrigerant compressor

control.
Heat X 3/4 HP
Sub-Cooler

Large connection
to minimize
pressure drop
Small connection

Capillary tube (sized by

computer program)

To liquid line connection

Tee in air handler

32-3009-03 19
 Application
Guide

Figure 8
High Lift Heat Pump Piping Schematic (Outdoor Unit above Air Handler)

Switchover Valve Discharge

Common Suction Line*
Outdoor Unit Compressor
Liquid
Suction Line from Sub-Cooler (3/8" O.D.)

Liquid Line * Tee into side or top of

Gas Line
common suction line to
(Insulate to avoid sweating problems)

prevent the drainage of

oil into the 3/8" line.
Up to 150 Feet

Note: The subcooler does not have to be

located inside the air handler cabinet, but
if it is located outside the cabinet, it should
be insulated to prevent possible water
damage due to sweating.

Sub-Cooler

Sub-Cooler
Capillary
Air Handler with
TXV Expansion Valve Coil

Air Handler

20 32-3009-03
 Application
Guide

Tables “H” (R-22) and “I” (R-410A) Table “H”

allow you to select the proper capillary
tube size, based on excess liquid line Capillary Tube Selection Table for R-22 Subcooler
pressure drop and system tonnage. (Total Liquid Line Pressure Drop Minus 35 PSI = Excess Pressure Drop)
The examples below illustrate typical
calculations for a system “A” (R-22) Excess Liquid Line Pressure Drop
System
and system “B” (R-410A). Tons 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
1.0
Given: R-22 Subcooler, 3/8" O.D. 1.5 30" x .042"
liquid line, 155 equivalent CAPILLARY TUBE
2.0
feet, 120 ft. lift (3 tons).
2.5 34" x .054"
Step #1 Friction loss from Table “A” CAPILLARY TUBE
page 7 = approx. 15 PSI 3.0
(note: rather than interpolate 3.5 20" x .064"
CAPILLARY TUBE
between 140 and 160 equiva- 4.0
lent feet , it is often simpler 5.0
to multiply the pressure drop 20" x .080"
6.0 CAPILLARY TUBE
for 100 ft. by the equivalent
7.5
length in hundreds of feet) (2) 32" x .080"
CAPILLARY TUBES
9.7 x 1.55 = approx. 15 PSI. 10.0

Step #2 Pressure drop due to lift

(120 x .5) = 60 PSI. Example: 3 ton system with 40 PSI excess pressure
Step #3 Total pressure drop drop requires 30" x .042" capillary tube.
(15 + 60) = 75 PSI.
Step #4 Excess liquid line pressure
drop (75 – 35) = 40 PSI.
Step #5 From Table “H”, 3 tons at Table “I”
40 PSI excess pressure
drop requires a 30" x .042" Capillary Tube Selection Table for R-410A Subcooler
capillary tube.
(Total Liquid Line Pressure Drop Minus 50 PSI = Excess Pressure Drop)
Given: R-410A Subcooler, 3/8" O.D. Excess Liquid Line Pressure Drop (PSI)
liquid line, 195 equivalent System
Tons 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
feet, 182 ft. liquid lift
1.0
(3 1/2 tons).
1.5
Step #1 Friction loss from Table 30" x .042"
“A-R” (13.3 x 1.95) = 25.9 PSI. 2.0 CAPILLARY TUBE
2.5
Step #2 Pressure drop due to lift
(182 x .43) = 78.3 PSI. 3.0 34" x .054"
3.5 CAPILLARY TUBE
Step #3 Total pressure drop
(25.9 + 78.3) = 104.2 PSI. 4.0 20" x .064"
CAPILLARY TUBE
Step #4 Excess pressure drop 5.0
(104 – 50) = 54 PSI. 6.0
Step #5 From Table “I,” 3 1/2 tons 7.5 20" x .080"
CAPILLARY TUBE
at 54 PSI excess pressure 10.0
drop requires a 30" x .042"
capillary tube.
Example: 3-1/2 ton system with 54 PSI excess pressure
drop requires 30" x .042" capillary tube.

32-3009-03 21
 Application
Guide

CHAPTER III 4 – Unusually high latent loads, which The remainder of the chapter will cover
require very low evaporator tempera- the field application of hot gas bypass,
Hot Gas Bypass tures, must limit capacity at reduced including, bypass valve selection (siz-
(Capacity Modulation) load or reduced outdoor temperatures. ing), sizing of the hot gas line, and infor-
(Evaporator coils may frost.) mation on accessories, such as solenoid
valves, auxiliary side connectors, etc.
Introduction 5 – Fluctuating loads which may lead to
excessive short cycling of equipment. Some of the concerns which will be
Why Capacity Modulation? covered are:
The typical residential cooling system How Can We Modulate
performs reasonably well, with a simple • Oil return
System Capacity?
on/off control (system thermostat). Introducing the hot gas at the evaporator
1 – The application of multiple systems,
inlet (side port distributor, or, auxiliary
While cooling loads vary considerably whenever practical, results in capacity
side connector), ensures adequate refrig-
from design conditions, to mild weather modulation, without sacrificing effi-
erant velocity for oil entrainment,
cooling, the changes are usually gradual. ciency, and should be the first consider-
through the evaporator, and any
Solar and internal loads as well as the ation. (Multiple systems also have the
suction lifts.
flywheel effect of the home and furnish- inherent advantage of not “putting all
ings tend to keep short cycling of the your eggs in one basket,” in the event of • Proper superheat in suction gas
system, in mild weather, within accept- a system failure.) If very precise control to compressor
able limits. Humidity control suffers of capacity modulation is required, hot
somewhat during mild weather, but gas bypass can be applied to the first The refrigerant metering device must
with a carefully sized system, it is stage system. An example of this could be a thermostatic expansion valve. The
usually tolerable. be two five ton systems matched with a valve will automatically compensate for
dual circuited 10 ton air handler. Apply- the highly superheated hot gas, and pro-
Loads, which vary more dramatically, ing hot gas bypass to the first stage sys- vide normally superheated suction gas
and over shorter periods of time, how- tem, only, provides modulation from to the compressor (thus preventing
ever, will often require some means of 10 tons to near 5 tons when both stages compressor overheating or slugging).
capacity modulation in order to: are called for. When first stage, only, is
called for, modulation is from 5 tons to • Undersizing of bypass valve
• Provide better humidity control near zero.
• Provide better temperature control Select a valve capable of bypassing the
• Reduce short cycling problems 2 – Cylinder unloading. This method maximum required, at the existing con-
of capacity modulation is very effective ditions, at the time of the minimum load.
• Avoid frosting of evaporator coils on larger systems (factory applied). The (Design load minus minimum load =
industry has found that cylinder unload- required bypass.) If the system is signifi-
Some examples of loads requiring
ing is not cost-effective on systems of cantly oversized, system capacity minus
capacity modulation are:
10 tons capacity or less. minimum load = required bypass.
1 – High percentages of outside air.
3 – Hot gas bypass. Hot gas bypass, Allow for pressure drops through the
The current emphasis on improving properly applied, provides very precise sideport distributor, or auxiliary side
indoor air quality often leads to high capacity modulation with a moderate connector, hot gas line, solenoid
outside air percentages. Code require- loss in efficiency. (Some energy is ex- valve, etc.
ments, or high exhaust requirements pended in pumping the bypassed gas
are also contributors. It is generally through the system, which provides no (An oversized bypass valve presents
accepted, that outside air percentages cooling effect.) no problem, since it is a modulating
greater than 25% require capacity type valve, and will open only as far
For applications where cylinder unload- as is required. To maintain the desired
modulation.
ing is not available, hot gas bypass is evaporator pressure.) If more bypass is
2 – On/off type loads such as lighting, undoubtedly the method of choice, if the required than is available from a single
industrial processes, etc. can result in application of multiple systems is not valve, two valves can be piped in paral-
wide variations in loads. practical. (Hot gas bypass can be com- lel. (Adjust both valves to open at the
bined with multiple systems to provide same pressure.)
3 – Special applications requiring very even more precise modulation.)
close control of humidity, temperature,
or both.

22 32-3009-03
 Application
Guide

Low head pressure problems are likely Operation – Hot Gas the valve to the limit of its stroke. The
to occur with hot gas bypass applica- Bypass Valve amount of pressure change required to
tions due to: move the valve from the closed position
The hot gas bypass regulator or dis-
to its rated open position varies with
1 – Operation at low outdoor ambients charge bypass valve automatically re-
the refrigerant used and the minimum
sponds to changes in suction pressure.
evaporator temperature desired. Most
2 – The bypassed gas bypasses the When the refrigerant evaporating pres-
manufacturers’ valve capacity ratings
condenser, further reducing head pres- sure is above the bypass valve setting,
are based on a 6°F change in suction
sure. (The published low ambient limit the valve remains closed. When the
temperature (approximately 9 PSI for
does not apply when hot gas bypass is cooling load drops, the suction pressure
R-22). In other words, a 6°F change in
utilized.) The application of a head pres- drops below the bypass valve setting
evaporator refrigerant temperature is
sure control is highly recommended. and the valve begins to open, bypassing
required to move the valve from the
a portion of the hot gas directly into the
fully closed position to the rated open
low side, thereby, maintaining the com-
position or from the rated open position
pressor suction pressure at a relatively
Hot Gas Bypass high level. The amount of valve opening
to the fully closed position. This same
valve would be able to open further if
The purpose of a hot gas bypass system is proportional to the change in the suc-
an 8°F or a 10°F change in evaporator
is to artificially load the compressor tion pressure, thereby, providing capac-
refrigerant temperature, which results
upon a decrease in evaporator load for ity modulation. Capacity reduction over
in a lower leaving air temperature,
one or more of the following reasons: a wide range is possible with proper
could be tolerated.
selection of the components. This is
• Prevent operation of the compressor shown in the sample problem. (See Note 1: The values given in manufactures’ catalogs are valve
capacities – not system capacities.
at excessively low suction pressures. page 23)
Note 2: Use of discharge bypass valves alone will not main-
This could cause compressor short tain adequate head pressure for proper operation under low
cycling, resulting in temperature and If the suction pressure continues to drop outdoors ambient operating conditions (below 50 – 55°F).*
humidity control variation. below the valve setting, the valve contin- It will be necessary to use an approved low ambient control-
ling device to maintain adequate high side pressure under
ues to open until the limit of its stroke is low ambient operating conditions. If bypassing 50% or more,
• Prevent a significant drop in evapora- reached. Most applications cannot toler- head pressure control is a must.
tor temperature where reasonably ate sufficient pressure change to open
constant conditions must be main-
tained. This is often necessary for
precise temperature control.
Figure 9
• Prevent frosting of the evaporator coil
causing serious loss of capacity be- Recommended Piping Hook-Up for Hot Gas Bypass
cause of restricted airflow, and
potential damage to the compressor.

Types of Discharge Bypass

Valves Available
Adjustable and non-adjustable discharge
valves are available. The adjustable type
uses a spring in the valve head and has
the advantage of greater flexibility. The
valve can be adjusted at the time of in-
stallation and the pressure setting will
not be affected by ambient or hot gas
temperature. It is recommended that the
adjustable type with an external
equalizer be used on all of the applica-
tions shown in this guide.

• Locate valve at the compressor end of the Hot Gas Line.

32-3009-03 23
 Application
Guide

The cutaway view (below) of a typical Application • Locate the bypass valve close to the
sporlan hot gas bypass valve illustrates compressor to avoid the accumula-
its construction. Figure #9 indicates the only recom- tion of significant amounts of liquid
mended piping hook up for hot gas by- refrigerant in the hot gas line when
When evaporator pressure (sensed pass applied to Trane U.P.G. products. not bypassing.
through the external equalizer line) falls Introducing the hot gas at the inlet to the
evaporator provides proper refrigerant • Externally equalized bypass valves
below the setpoint of the valve, spring are a must.
pressure against the diaphragm over- velocity for oil return through the evapo-
comes evaporator pressure and begins rator and suction lifts, if present (regard- • Adjustable bypass valves are recom-
to move the piston off its seat. This al- less of the amount being bypassed). mended.
lows the high pressure, hot gas to flow Good mixing of the bypassed gas with • Do not apply evaporator pressure
through the valve to maintain low side the evaporating refrigerant takes place regulating valves to Trane D.P.G.
pressure. When evaporator pressure and the system expansion valve com- products (Trane or American
has fallen approx. 9 PSI (R-22) below pensates for the added superheat. Standard).
the setpoint, the valve will be open to
its rated position. This hook-up does require either a side-
port distributor or an auxiliary side con-
When evaporator pressure rises above nector. In some cases, depending on the Heat Pump Systems
the setpoint, it forces the valve closed. size of the original distributor and the When applying hot gas bypass to a heat
required amount of bypass, a larger pump system:
distributor could be required.
A — The hot gas bypass valve inlet must
An externally equalized bypass valve is be connected to the discharge line be-
recommended for all applications. tween the compressor and the
switchover valve.
Bypass valves should be sized gener-
ously, in order to accommodate pressure B — A hot gas solenoid valve must be
drops in the hot gas line, etc. installed upstream of the bypass valve,
Figure 10 and wired so that it opens in the cooling
A hand valve installed upstream of the mode only.
bypass valve facilitates pump down for
Typical Sporlan Hot Gas service operations. The bypass valve C — Low head pressure problems
Bypass Valve must be installed close to the tee in the during bypass may occur, requiring
discharge line, to prevent the accumula- some means of head pressure control.
tion of liquid R-22 in the hot gas line
when not bypassing. External equalizer D — If a 24 volt solenoid valve is used,
lines should be connected approxi- be sure that adequate transformer
mately 6" downstream of the TXV capacity is available.
Thermal Bulb. (The hot gas bypass
valve external equalizer can be con- E — Apply multiple systems whenever
nected to the suction line near the out- possible, to achieve capacity modula-
door unit if desired.) tion.

F — In most cases, if cooling is required

Hints to Remember When
at low outdoor temperatures, it is prob-
Applying Hot Gas Bypass ably not a good heat pump application.
• The refrigerant metering device must
be a thermostatic expansion valve.
• Proper refrigerant velocities must
be maintained in the evaporator and
suction lifts (if any). This dictates the
introduction of the hot gas at the
evaporator inlet.
• Low ambient cooling problems must
be considered. (Head pressure con-
trol is often required.)

24 32-3009-03
 Application
Guide

Selecting The Hot Gas very often, require the application of tions. Table “E” is based on the amount
a head pressure control device. (tons) of bypass required.
Bypass Valve
Pressure drops in the hot gas line, Chart “X,” page 24, can be used to calcu-
The bypass valve must be capable of
solenoid valve (if used), side-port dis- late the pressure drop in the hot gas line,
bypassing the difference between the
tributor (or auxiliary side connector if desired.
design load and the anticipated mini-
mum load (at the conditions existing plus distributor), all tend to reduce the Table “F” below, lists information on
when the minimum load occurs). capacity of the hot gas bypass valve. Sporlan Bypass Valves. (The selections
(Size it generously.) in Table “F,” assume a 26°F evaporating
Anticipated lower head pressures at temperature, and 80°F condensing tem-
the minimum load conditions (further Table “E” provides a simple method, for perature, for the minimum load condi-
aggravated by the fact that the bypassed the selection of a hot gas bypass valve, tions.) The adjustment range of 0 to
gas is bypassing the condenser) will and the hot gas line, for average condi- 80 PSIG is recommended for R-22.

Table “E”
Quick Selection Table For Hot Gas Bypass Valves
R-22 Refrigerant
Amount of Bypass Required
(Design Load Minus Minimum Load)
0 – 2 Tons 2.5 – 4 Tons 4.5 – 8 Tons 8.5 – 10 Tons
Sporlan Sporlan Sporlan Sporlan
Hot Gas Bypass Valve ADRSE-2 ADRPE-3 ADRHE-6 DRHE-6
(or Equiv.) (or Equiv.) (or Equiv.) (or Equiv.)
Recommended
Hot Gas Line O.D.
Up to 50 Eq. Ft. 1/2" O.D. 5/8" O.D. 3/4" O.D. 7/8" O.D.
51 to 100 Eq. Ft. 1/2" O.D. 5/8" O.D. 7/8" O.D. 7/8" O.D.

Table “F”
Discharge Bypass Valve Capacities – Tons
Capacities based on 6°F evaporator temperature change from closed to rated opening, discharge temperature 30°F above isentropic compression, 25°F
superheat at the compressor, 0° subcooling, and includes both the hot gas bypassed and liquid refrigerant for desuperheating, regardless of whether the
liquid is fed through the system thermostatic expansion valve or an auxiliary desuperheating thermostatic expansion valve.
Minimum Allowable Evaporator Temperature At The Reduced Load – °F

Adjustment 40 26 20 0 -20 -40

Valve Range Condensing Temperature – °F
Refrigerant Type PSIG 80 100 120 80 100 120 80 100 120 80 100 120 80 100 120 80 100 120
Adjustable Models
ADRI–1-1/4
ADRIE–1-1/4 0/55 — — — 0.35 0.45 0.56 0.41 0.53 0.66 0.58 0.75 0.93 0.54 0.69 0.87 0.49 0.64 0.80

ADRS–2 0/30 — — — — — — — — — 2.93 3.77 4.73 2.82 3.63 4.57 2.72 3.51 4.42
ADRSE–2 0/80 2.65 3.40 4.26 2.69 3.45 4.34 2.71 3.48 4.37 2.88 3.70 4.66 — — — — — —
22 ADRP–3 0/30 — — — — — — — — — 5.56 7.16 9.00 5.61 7.23 9.10 5.47 7.06 8.90
ADRPE–3 0/80 4.50 5.78 7.25 4.72 6.06 7.61 4.80 6.17 7.75 5.24 6.73 8.47 — — — — — —
0/30 — — — — — — — — — 10.5 13.5 17.0 10.6 13.7 17.2 10.3 13.3 16.7
ADRHE–6
0/80 6.89 8.84 11.1 7.46 9.58 12.0 7.68 9.87 12.4 8.12 11.4 14.4 — — — — — —
Adjustable “Remote Bulb” Models
12 25/35 5.51 7.11 8.96 4.86 6.26 7.89
These models are recommended for air conditioning
22 DRHE–6 55/70 14.3 19.0 24.0 12.7 16.4 20.6
temperature ranges only.
134a 25/35 7.03 9.26 11.9 6.06 7.98 10.2
502 65/80 13.9 18.2 22.6 12.6 15.8 19.4
32-3009-03 25
 Chart “J”
Pressure Drop in R-22 Vapor Lines
5 Tons of Bypass with a 7/8" O.D. Hot
Gas Line = 5.4 PSI/100' Pressure Drop.
PRESSURE DROP — PSI / 100 FT.
0.1 .2 .3 .4 .5 .6 .7 .8 .9 1.0 2 3 4 5 6 7 8 9 10

80°

L
R

PE
PO

TY
VA

D
D
D
D
°F

OD

OD
OD
OD
OD

OD
OD
OD

OD
20

"O
"O
"O
"O
N
R

/8"

/8"

/8"
/8"
/8"
/8"

/8"

/8"
O

/8"
P

1
1

1/2
5/8
3/4
7/8
ED

-
-

4-1

2-1
VA

2-5

1-3
3
3-5
5

1-1
1-5
BAS
ED

)
T
Guide

(°F
RA

P.
TU

M
A

TE
)S

D.
(°F

N
O
P.

26
C
EM

90 100 110 120

.T

S
AP

E
V

N
E

LI
E
G
Application

R
E
N

HA
LI

ISC
N

D
IO
CT
SU
0 10 20 30 40 50 0 0 0 0
–4 –3 –2 –1
0
–5
0
–6

NOTE: PRESSURE DROPS DO NOT ALLOW

FOR PULSATING FLOW. IF FLOW
IS PULSATING, USE NEXT LARGER
PIPE SIZE.

1 2 3 4 5 10 20 30 50 100 200 300 500 1000 2000 3000 5000 10,000 20,000 30,000
FLOW RATE — LB / MIN

32-3009-03
 Application
Guide

Figures 11 and 12 on this page and 13 a 26° evaporating temperature (9.46 x Figure 11
on page 26 provide information on .95 = approx. 9.0 tons). The above values
accessories for hot gas bypass applica- are based on a 10 PSI pressure drop Auxiliary Side Connectors
tions, plus capacity multipliers for eva- across the solenoid valve. If no more
porating temperature changes other than a 5 PSI pressure drop across the ASC
than the standard 6°. (See Figure 12.) solenoid valve can be tolerated, its Distributor Connection Sizes (Inches)
capacity is 6.77 x .95 or approx. 6.4 tons Type ASC Type Inlet Outlet Auxiliary
Figure 11 lists compatible distributor/ of bypass. (Selecting a hot gas bypass Number Number ODM ODF ODF
auxiliary side connector combinations, valve with some excess capacity, would 1620, 1622 ASC-5-4 5/8 5/8 1/2
complete with fitting sizes. (O.D.M. = allow us to use the 10 PSI valve.) The 1112, 1113 ASC-7-4 7/8 7/8 1/2
outside diameter, male and O.D.F. = solenoid valve’s capacity would be 1115, 1116 ASC-9-5 1-1/8 1-1/8 5/8
outside diameter, female.) derated somewhat more, assuming a 1117, 1126 ASC-11-7 1-3/8 1-3/8 7/8
Figure 12 lists bypass valve capacity condensing temperature of 80° on a 1125, 1127
ASC-13-9 1-5/8 1-5/8 1-1/8
multipliers for evaporating temperature mild day. (The Table in Figure 13 is based 1143
changes, other than 6°F. Note that the on a 100° condensing temperature.)
capacity multiplier for a 2°F evaporating Figure 14, page 27, lists capacities for
change is .70 (26° evaporating tempera- liquid line solenoid valves. (Do not con- Figure 12
ture). A 26° refrigerant evaporating fuse Figure 14 with Figure 13, which
temperature, with normal airflows’ covers hot gas solenoid valves.) Much
Capacity Multipliers
will result in a coil surface temperature larger port sizes are required to handle
above 32°F. (Frosting should not occur.) For Evaporator Temperature Changes
R-22 vapor. Other Than 6°F Nominal Change
Figure 13 lists capacities of hot gas sole- Evaporator Evaporator Temperature °F
The circled values in Figure 14 indicate
noid valves. Hot gas solenoid valves are that the ME9S230 (or 240) liquid line Temp.
not usually required on straight cooling Change Refrigerant 40 26 20 0 and
solenoid valve has a capacity of 8 tons °F Below
applications, since pump down is not at a 3 PSI pressure drop across the valve
normally permitted. (The hot gas sole- 12 & 134a 0.65 0.65 0.65
(R-22). 2° 0.65
noid valve is required on heat pump 22 & 502 0.72 0.70 0.70
applications, however, in order to dis- Could we use this solenoid valve on a 4°
12 & 134a 0.80 0.80 0.80
0.74
able the hot gas bypass during the 10 ton system? The answer is yes, if the 22 & 502 0.87 0.85 0.85
heating mode.) 4.7 PSI pressure drop does not result 12 & 134a 1.11 1.11 1.11
8° 1.09
in a total liquid line pressure drop of 22 & 502 1.17 1.15 1.11
Note that a ME19S250 (or 270) hot gas over 35 PSI (3.0 PSIG x (10/8)2 = 4.7 PSI). 12 & 134A 1.22 1.20 1.19
solenoid valve (R-22) has a capacity of 10° 1.11
22 & 502 1.34 1.27 1.25
9.46 tons x a correction factor of .95 for

32-3009-03 27
 Application
Guide

Figure 13
Hot Gas Solenoid Valve Capacities – Tons
Capacities based on 100°F condensing temperature, isentropic compression plus 50°F, 40°F evaporator and 65°F suction gas.
For other evaporator conditions use the multipliers in the table below.
Valve Type Refrigerants
12 22 134a 502
“E” Series
“A” & “B” Extended Connections Pressure Drop Across Valve Port – PSI
Series Connections Inches 5 10 5 10 5 10 5 10
A3F1 — 1/4 SAE
0.26 0.35 0.37 0.51 0.31 0.42 0.30 0.42
A3S1 — 1/4 or 3/8 ODF
— E5S120 1/4 ODF
0.61 0.84 0.88 1.22 0.74 1.00 0.72 1.00
— E5S130 3/8 ODF
MB6F1 — 3/8 SAE
MB6S1 ME6S130 3/8 ODF 1.01 1.43 1.51 2.10 1.27 1.74 1.30 1.70
MB6S1 ME6S140 1/2 ODF
MB9F2 — 3/8 SAE
— ME9S230 3/8 ODF 1.50 0.21 2.17 3.04 1.80 2.50 1.80 2.50
MB9S2 ME9S240 1/2 ODF
MB10F2 — 1/2 SAE
— ME10S240 1/2 ODF 2.30 3.20 3.37 4.69 2.80 3.90 2.80 3.80
MB10S2 ME10S250 5/8 ODF
MB14S2 ME14S250 5/8 ODF 3.20 4.40 4.58 6.40 3.80 5.30 3.80 5.30
MB19S2 ME19S250 5/8 ODF
4.70 6.50 6.77 9.46 5.70 7.90 5.70 8.00
MB25S2 ME19S270 7/8 ODF
MB25S2 ME25S270 7/8 ODF
7.50 10.5 10.8 15.1 9.10 12.7 8.90 12.5
MB25S2 ME25S290 1-1/8 ODF

Correction Factors
For evaporator temperatures at the reduced load condition
Evaporator
Temperature °F 40° 26° 20° 0° -20° -40°
Multiplier 1.00 .95 .93 .87 .81 .75

28 32-3009-03
 Application
Guide

Figure 14
Liquid Line Solenoid Valve Capacity Selection Table
Type Number Tons of Refrigeration

“E” Series
“A” & “B” Extended Pressure Drop – PSI
Series Connections
Port
With Manual Lift Stem Connections Size 1 2 3
Normally Closed (Inches) (Inches) 12 22 134a 502 12 22 134a 502 12 22 134a 502
A3P1 — — — 3/8 NPT Female
A3F1 — — — 1/4 SAE Flare
.101 0.7 0.9 0.8 0.6 1.0 1.3 1.2 0.8 1.2 1.6 1.5 1.0
A3S1 — E3S120 — 1/4 ODF Solder
A3S1 — E3S130 — 3/8 ODF Solder
— — E5S120 — 1/4 ODF Solder
.150 1.2 1.6 1.5 1.1 1.8 2.3 2.1 1.5 2.2 2.8 2.6 1.9
— — E5S130 — 3/8 ODF Solder
— MB6P1 — — 3/8 NPT Female
— MB6F1 — — 3/8 SAE Flare
3/16 2.2 2.9 2.7 1.9 3.1 4.0 3.8 2.6 3.8 4.9 4.6 3.2
— MB6S1 — ME6S130 3/8 ODF Solder
— MB6S1 — ME6S140 1/2 ODF Solder
— MB9P2 — — 3/8 NPT Female
— MB9F2 — — 3/8 SAE Flare
9/32 3.6 4.7 4.4 3.0 5.1 6.6 6.2 4.3 6.2 8.0 7.5 5.2
— — — ME9S230 3/8 ODF Solder
— MB9S2 — ME9S240 1/2 ODF Solder

32-3009-03 29
Application
Guide

How To Estimate B — What are the sensible and latent

loads at 60° D.B. outdoors?
Minimum Loads (Assume 80% rel. humidity.)
We are not always given minimum
loads, which are necessary, in order Sensible Loads
to determine the required amount of Internal (constant) = 98200 BTUH
bypass. A sample calculation follows: Transmission (loss)
6600 x 78 – 60 = -6253 BTUH or,
A small commercial application 97 – 78
located in Tyler, TX has the following
requirements: 6600 x [78 – 60] = 6253
19
Outdoor design = 97° D.B./ 76° W.B. (103
grains water vapor per lb. of dry air.) Outside air (loss) =
1700 x 1.08 x (78 – 60) = –33048 BTUH
Indoor design = 78° D.B./ 64.9° W.B.
(72 gr./lb.) Net sensible load @ 60° outdoors =
58899 BTUH
1700 CFM of outside air is required.
Latent loads
We have been given the following
Internal = 800 BTUH
information:
Outside air (loss) 1700 x .68 x
Internal sensible load (constant) = (72 gr. – 62 gr.) = -11560 BTUH
98200 BTUH
Net latent load @ 60° outdoors
Transmission load (sensible) = –10,760 BTUH
6600 BTUH
Since the latent load is negative, only
Internal latent load = 800 BTUH the sensible load will be considered.
Design sensible load = 139684 BTUH
A — What are the total sensible and
latent loads at design conditions? Sensible load @ 60° outdoors =
58899 BTUH
Outside air sensible load = Excess sensible capacity = 80785 BTUH
1700 x 1.08 x (97 – 78) or 34884 BTUH (139684 minus 58899)

Outside air latent load = Note: If the system is significantly over-

1700 x .68 x (103 – 72) or 35836 BTUH sized at design conditions, use design
system capacity minus minimum load.
Sensible Loads
Internal = 98200 BTUH Assuming 70% sensible capacity, at 60°
Transmission = 6600 BTUH D.B. the required bypass (total capacity)
Outside air = 34884 BTUH = 80785 ÷ .70 or 115407 BTUH (total)
(approx. 9.6 tons).
Total (HS) 139,684 BTUH
One DRHE-6 (or two ADRHE-6, piped
Latent Loads in parallel) will provide some excess in
Internal = 800 BTUH rated capacity, to allow for pressure
Outside air = 35836 BTUH drops in the hot gas line, etc. (See tables
“E” or “F”)
Total (HL) 36,636 BTUH
If two stages of cooling are provided, the
first stage, only, would require approx.
5 tons of bypass.
115470 = 57704 BTUH
2
57704 = 4.8 tons
12000

30 32-3009-03
 Refrigerant Pipe Sizing
Worksheet

Project Application
________________________________________ Outdoor Model ____________________________________
Address Guide
________________________________________ Indoor Model ____________________________________
________________________________________ A.R.I. Capacity ____________________________________
■ Cooling ■ Heat Pump
Piping Runs

Horizontal Lengths__________________________________________________________ = ________________ft

Linear

Vertical Lengths ____________________________________________________________ = ________________ft

Total Piping Run = (a) ______________ft

_________ Short Elbows _________ 45° Elbows __________ Soleniod Valve

Fittings and Refrigerant Specialties

_________ Long Elbows _________ Sight Glass(1)

(1)
Sight glasses are not recommended on Tyler built units.

LIQUID LINE GAS LINE

Fittings/Accessories Equivalent Fittings/Accessories Equivalent
Tubing Equivalent Length Tubing Equivalent Length
Equivalent Lengths

Size Quantity Length Subtotals Size Quantity Length Subtotals

_______ ____________ x _________ = ___________ _______ ____________ x _________ = ___________

_______ ____________ x _________ = ___________ _______ ____________ x _________ = ___________

_______ ____________ x _________ = ___________ _______ ____________ x _________ = ___________

_______ ____________ x _________ = ___________ _______ ____________ x _________ = ___________

Liquid line fittings/accessories equivalent total = (b) ________ ft Gas line fittings/accessories equivalent total = (x) ________ ft

LIQUID LINE GAS LINE

Actual Piping Lengths [From (a)] (a) ___________________ ft (a) _____________________ft

Frictional Losses

Fittings/Accessories Equivalent Feet (b) or (x) (b) + __________________ ft (x) + ft

Total Equivalent Piping Run = ft ft

P.D./100 ft
Pressure Drop/Foot x psi/ft x psi/ft
Pressure Losses and Gains

100
= 100
=

Frictional Pressure Loss = (c) ________________ p.s.i. p.s.i.

GAS LINE PRESSURE DROPS

Hydrostatic Force
Liquid Line Only

Vertical Separation between Indoor/Outdoor = ______________ ft I. If P. D. is less than 3 psi, P. D. in

acceptable range.
II. P. D. between 3 and 6 psi, check capacity loss
(Chart B – Refrigerant Piping Manual).
R-22 Hydrostatic Force = x 0.50 psi/ft III. If P. D. exceeds 6 psi, capacity loss may
require oversize pipe or larger equipment
size because of capacity losses.
If (d) is greater than 25 psi (See Note B) (d) ___________ psi
NOTES
A. Heat Pump Systems: Always add (+)
(d value) to (c value) for system total.
Air Conditioning Systems:
Frictional Loss (c) ________________ Condensing unit above Indoor Evaporator:
subtract (–) (d value) from (c value).
System Loss

Condensing unit below Indoor Evaporator:

Hydrostatic Force (See Note A) (d) ± Add (+) (d value) to (c value).
B. A hydrostatic force greater than 25 psi may
not provide sufficient pressure available to
overcome frictional losses on Heat Pump
Total = ______________ psi Systems and Air Conditioning Systems with
the outdoor condensing unit below the indoor
Liquid Pressure Drop Can Not exceed 35 PSI with R-22 or 50 PSI with R-410A evaporator unit.

© American Standard Inc. 1993 Pub. No. 22-3217-01 P.I. (L)

32-3009-03 31
 Standard Piping Size Oversized Piping
Nominal
Tonnage #/Min
ARI (1)
Capacity Gas
Pipe Size
Liquid
Application
Pressure Drops(1)
Gas Liquid
Lbs. R-22 (100 ft.)
Gas Liquid Gas
Pipe Size
Liquid
Pressure Drops(1)
Gas Liquid
Lbs. R-22 (100 ft.)
Gas Liquid
(100 ft.) (100 ft.) (100 ft.) (100 ft.)

1 3.00 12,000 5/8 1/4

Guide
2.60 17.0 0.3 1.50 5/8 5/16 2.60 5.0 0.30 2.30
3.75 15,000 3.40 26.0
1 1/2 3.75 15,000 5/8 1/4 3.40 26.0 0.3 1.50 5/8 5/16 3.40 7.8 0.30 2.30
4.50 18,000 4.80 38.0(4) 3/4 5/16 1.80 11.0 0.40 2.30
2 5.25 21,000 3/4 5/16 2.60 14.0 0.4 2.30 7/8 3/8 1.20 3.8 0.50 3.80
6.00 24,000 3.40 17.0 1.50 4.8
6.75 27,000 4.10 20.0 1.80 5.8
2 1/2 6.75 27,000 3/4 5/16 4.10 20.0 0.4 2.30 7/8 3/8 1.80 5.8 0.50 3.80
7.50 30,000 5.10 25.0(4) 2.30 7.0
8.25 33,000 6.00 32.0(4) 2.75 8.7
3(5) 8.25 33,000 7/8 5/16 2.75 32.0(4) 0.5 2.30 7/8(2) 3/8 2.75 8.7 0.50 3.80
9.00 36,000 3.20 36.0(4) 7/8(2) 3/8 3.20 10.2 0.50
9.75 39,000 3.70 41.0(4) 7/8 HP(2) 3.70 11.8 0.50(3)
3 1/2(5) 10.00 40,000 7/8 5/16 3.90 45.0(4) 0.5 2.30 1 1/8 3/8 1.00 12.0 0.90 3.80
(4)
10.50 42,000 4.10 48.0 1.10 13.0
11.25 45,000 4.70 54.0(4) 1.20 14.0
4 11.25 45,000 1 1/8 3/8 1.20 14.0 0.9 3.80 1 1/8 1/2 1.20 2.8 0.90 7.30
12.00 48,000 1.40 16.0 1.40 3.9
12.75 51,000 1.60 18.0(4) 1.60 4.0
5 14.00 56,000 1 1/8 3/8 1.90 22.5(4) 0.9 3.80 1 3/8 1/2 0.64 4.8 1.30 7.30
14.75 59,000 2.15 24.5(4) 0.70 5.1
15.50 62,000 2.30 26.0(4) 0.76 5.6
6 16.50 66,000 1 1/8 3/8 2.45 27.0(4) 0.9 3.80 1 3/8 1/2 0.80 6.0 1.30 7.30
17.25 69,000 2.80 31.0(4) 0.90 6.8
18.00 72,000 3.20 35.0(4) 1.00 7.6
7 1/2 21.50 86,000 1 3/8 1/2 1.50 10.0 1.3 7.30 1 5/8 5/8 0.65 3.2 1.90 11.80
22.50 90,000 1.65 12.0(4) 0.70 3.7
24.50 98,000 1.90 14.0(4) 0.83 4.2
10 29.00 116,000 1 3/8 1/2 2.80 17.5(4) 1.3 7.30 1 5/8 5/8 1.20 5.5 1.90 11.80
30.00 120,000 2.90 19.0(4) 1.30 6.0
31.25 125,000 3.00 21.0(4) 1.40 6.5
(1) (4)
Adjusted for net capacity. Velocity exceeds 300 FPM — cannot use a quick closing device,
(2)
Max line size on vertical runs and heat pump systems. such as a solenoid valve.
(3) (5)
7/8 = 0.50# 1 1/8 = 0.90# Standard size for liquid line — pre 1992 models is 5/16 inch,
1992 and later models — 3/8 inch liquid line is standard.

Equivalent Lengths Of Valves And Fittings

O.D Line Short Radius Long Radius Solenoid Sight
Size (in.) 45° ELL ELL ELL Value Glass

1/4 2.0 4.6 3.1 17 1.2

5/16 2.1 4.6 3.1 20 1.4
3/8 2.2 4.7 3.2 22 1.6
1/2 2.4 4.7 3.2 24 1.7
5/8 2.9 5.7 3.9 25 2.3
3/4 3.3 6.5 4.5 25 2.9
7/8 3.9 7.8 5.3 28 3.7
1 1/8 1.4 2.7 1.9 29 2.5
1 3/8 1.6 3.2 2.2 33 2.7
1 5/8 1.9 3.8 2.6 34 3.0

32 32-3009-03
 Application
Guide

Notes

32-3009-03 33
Application
Guide

Notes

34 32-3009-03
 Application
Guide

Notes

32-3009-03 35
Literature Order Number
File No. Pub. No. 32-3009-03 7/00
Supersedes Pub. No. 32-3009-02 1/00
Stocking Location P.I. (L)

Since The Trane Company has a policy of continuous product improvement, it reserves the right to change
design and specifications without notice.