user manual

MD cooling tower
I N STA L L AT I O N - O P E R AT I O N - M A I N T E N A N C E

Z0602117_G ISSUED 04/2019 READ AND UNDERSTAND THIS MANUAL PRIOR TO OPERATING OR SERVICING THIS PRODUCT
 contents

This manual contains vital information for the proper installation and
Note operation of your cooling tower. Carefully read the manual before
installation or operation of the tower and follow all instructions.
Save this manual for future reference..

Overview....................................................................................................................................... 3
Tower Location............................................................................................................................ 4
Tower Shipment.......................................................................................................................... 4
Receiving Tower.......................................................................................................................... 5
Hoisting Tower............................................................................................................................. 5
Tower Installation........................................................................................................................ 6
Motor Wiring................................................................................................................................ 9
Mechanical Equipment........................................................................................................... 11
Tower Startup........................................................................................................................... 12
Tower Operation....................................................................................................................... 15
Freezing Weather Operation................................................................................................. 16
Water Quality and Blowdown............................................................................................... 19
Cooling Tower Inspection and Maintenance..................................................................... 21
Belt Tensioning......................................................................................................................... 22
Sheave Alignment.................................................................................................................... 24
Fan Motor Access and Removal.......................................................................................... 25
Cold Water Basin Access / Air Inlet Louver Removal......................................................27
Access Door Operation......................................................................................................... 28
Drift Eliminator Removal and Replacement....................................................................... 28
Distribution System Maintenance........................................................................................ 30
Schedule of Tower Maintenance.......................................................................................... 31
Seasonal Shutdown Instructions......................................................................................... 34
Maintenance Schedule............................................................................................................37
Troubleshooting........................................................................................................................ 38

The following defined terms are used throughout this manual to

bring attention to the presence of hazards of various risk levels, or
to important information concerning the life of the product. Also,
please observe all Caution and Warning labels on the tower.

Indicates presence of a hazard which can cause severe personal

Warning injury, death or substantial property damage if ignored.

Indicates presence of a hazard which will or can cause personal

Caution injury or property damage if ignored.

Indicates special instructions on installation, operation or mainte-

Note nance which are important but not related to personal injury hazards.

2
 overview

This User Manual as well as those offered separately on motors, fans,

Geareducer, couplings, drive shafts, float valves, pumps, etc., are intended to
assure that this cooling tower serves you properly for the maximum possible
time. Since product warrantability may well depend upon your actions, please
read this User Manual thoroughly prior to operation.
This User Manual provides information regarding general cooling tower in-
stallation and operation. Any deviation from, change or modification to, the
User Manual, the original design conditions or the original intended use of the
equipment may result in improper installation and/or operation of the tower.
Any such deviation, change or modification shall be the responsibility of
the party or parties making such deviation, change or modification. SPX
Cooling Technologies, Inc. expressly disclaims all liability for any such deviation,
change or modification. The equipment shall be warranted in accordance with
the applicable SPX Cooling Technologies Certification of Limited Warranty.
If you have questions about the operation and/or maintenance of this cooling
tower, and you don’t find the answers in this manual, please contact your
Marley sales representative. When writing for information, or when ordering
parts, please include the serial number shown on the cooling tower nameplate.

Safety First
The location and orientation of the cooling tower can affect the safety of those
responsible for installing, operating or maintaining the tower. However, since
SPX Cooling does not determine the location or orientation of the tower, we
cannot be responsible for addressing those safety issues that are affected
by the tower’s location or orientation.

The following safety issues should be considered by those respon-

Warning sible for designing the tower installation.
• Access to and from the collection basin
• Access to and from mechanical access door(s)
• The possible need for ladders (either portable or permanent) to
gain access to the mechanical access door(s)
• The possible need for external mechanical access platforms
• Access issues due to obstructions surrounding the tower
• Lockout of mechanical equipment
• The possible need for safety cages around ladders
• The need to avoid exposing maintenance personnel to the poten-
tially unsafe environment inside the tower.

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 overview

Those are only some of the safety issues that may arise in the design
process. SPX strongly recommends that you consult a safety engi-
neer to be sure that all safety considerations have been addressed.

Several options are available that may assist you in addressing some of these
personnel safety concerns, including:
— mechanical access platform and ladder
— ladder extensions (used where the base of the tower is elevated)
— safety cages for ladders
— safety gate for ladders

Tower Location
Space available around the tower should be as generous as possible to pro-
mote ease of maintenance—and to permit freedom of airflow into and through
the tower. If you have questions about the adequacy of the available space
and the intended configuration of the tower, please contact your Marley sales
representative for guidance.
Prepare a stable, level support foundation for the tower, utilizing weight, wind
load, and dimensional information appearing on appropriate Marley submittal
drawings. Supports must be level to insure proper operation of the tower.

The cooling tower must be located at such distance and direction

Warning to avoid the possibility of contaminated tower discharge air being
drawn into building fresh air intake ducts. The purchaser should ob-
tain the services of a Licensed Professional Engineer or Registered
Architect to certify that the location of the tower is in compliance
with applicable air pollution, fire, and clean air codes.

Tower Shipment
Unless otherwise specified, MD cooling towers ship by truck on trailer(s),
which lets you receive, hoist, and install the tower in one continuous operation.
Single-cell towers ship on one truck. Multicell towers, depending on their size,
and towers with access options (i.e. factory assembled access platforms) may
require more than one truck.
Responsibility for the condition of the tower upon its arrival belongs to the
truck driver—as does the coordination of multiple shipments, if required. Each
tower has recommended tie down instructions by which they should be se-
cured to the flatbed. Drivers should follow these instructions when securing
the tower to the flat-bed.

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 receiving and hoisting

Receiving Tower
Prior to unloading the tower from the delivering carrier, inspect the shipment
for evidence of damage in transit. If damage is apparent, note the freight bill
accordingly. This will support your future recovery claim.
Find and remove the installation instruction drawings and bills of material
located in a plastic container in the cold water basin. This information should
be kept for future reference and maintenance purposes.

Hoisting Tower
All models consist of two modules per cell. Both modules have hoisting clips.
Detailed hoisting drawing are included in the literature package.

MD upper and lower modules must be hoisted and set separately.

Caution Do not preassemble modules prior to hoisting.

A Hoisting-Installation label which has hoisting dimensional information is

located on the side casing of the tower modules. Remove tower from the car-
rier and hoist into place according to the instructions on the label.

Hoisting clips are provided for ease of unloading and positioning

Warning tower. For overhead lifts or where additional safety is required,
safety slings should also be placed under the tower. Under no
circumstances should you combine the top and bottom modules
of modular models and attempt to hoist them at the same time by
utilizing the hoisting clips alone!

OFFSET MAY BE REQUIRED OFFSET MAY BE REQUIRED

FOR BALANCED LIFT FOR BALANCED LIFT
CENTER OF CENTER OF
TOWER TOWER

LIFTING LIFTING
SLING SLING

WIDTH WIDTH

70° MAX
BOTH MODULES

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 installation

Tower Installation
These installation instructions are intended to help you prepare
Note before your tower arrives. If discrepancies exist between these
instructions and those shipped with the tower, the instructions
shipped with the tower will govern.

1. Prior to placement of the tower, confirm that the supporting platform is

level, and that the anchor bolt holes are correctly located in accordance
with Marley drawings.
2. Place bottom module on your prepared supports, aligning anchor bolt
holes with those in your supporting steel. Make sure that the orientation
agrees with your intended piping arrangement. Attach tower to supporting
steel with four 5⁄8" diameter bolts and flat washers (by others). Position
flat washers between the bolt head and the tower bottom flange.
3. Before setting top module in place on bottom module, clean any debris
from the top of the bottom module. Ensure that the fill surface is free from
debris and all fill packs are level. Recommended tie-down instructions are
provided to the truck driver upon tower pickup. If damage occurs to the
tower due to tie-down procedures other than those recommended in the
drawing, it should be noted upon arrival. Remove the protective paper off
the sealing gasket tape before setting the top module and ensure there is
coverage around the entire perimeter. Place the top module on the bottom
module, aligning mating holes as it is set in place. Make sure that the ori-
entation of the top module agrees with your intended piping arrangement.
Sections are 180° reversible with respect to each other. Pay close attention
to face designations on sales orientation drawings e.g. Face A, Face B,
etc. Use drift pins to align bolt holes during the assembly of the top and
bottom modules as the top is lowered into place. Use care when setting
the modules as lifting and resetting the top module will compromise the
sealing gasket between the two sections, possibly resulting in a leaking
joint. If the top module must be reset, it may be necessary to remove the
sealing gasket tape and replace.

Gasket details must be followed correctly or leaks may occur that

Note will not be covered under warranty.

4. Attach top module to bottom module with fasteners provided—according

to “MD Field Installation Manual”.

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 installation

If tower purchased is one fan cell only, ignore steps 4 through 8.

Note
5. If collection basins are to be equalized by the use of Marley standard
flumes, unbolt the coverplate from the basin of the cell just installed. The
coverplate is located in the collection basin depressed section end.
6. Unbolt temporary coverplate from the basin of the second cell and set
the bottom module of the second cell in place. Align anchor bolt holes
and flume openings in basin sides.
7. Install flume according to “MD Field Installation Manual”.

It is important that the cells be firmly anchored before the flume is

Note attached to the 2nd cell.

8. Repeat steps 2 through 4 for the second top section.

9. Repeat steps 5 through 8 for any remaining cells.
10. Attach your cold water supply piping to the cold water basin outlet con-
nection in accordance with drawing instructions. Use gaskets where
recommended.

Do not support your pipe from the tower or outlet connection—sup-

Caution port it externally.

Normally, one of the following three outlet arrangements is provided:

Side or End suction connection: This is a factory-installed, galvanized
pipe nipple, extending horizontally from the side or end of the cold water
basin. It is both beveled for welding—and grooved for a mechanical cou-
pling. If a weld connection is used, it is recommended that the weld area
be protected against corrosion. Cold galvanizing is suggested, applied
according to the manufacturer’s instructions.

Protect adjacent areas from excessive heat and sparks during weld-
Caution ing or damage could occur.

Bottom outlet connection: This is a factory-installed, circular opening

in the cold water basin floor of one or more cells. An appropriately sized
circular opening has been drilled to 125# ANSI B16.1 flat-face flange
specifications. A full faced gasket and appropriately sized bolts (by others)
must be used for proper outlet function.

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 installation

Side outlet sump connection: For shipping purposes, sumps are at-
tached upside down in the basin to prevent damage. Sumps are to be
installed in the square opening in the floor of the cold water basin of one
or more cells—sealed against leakage, and attached by machine bolts,
according to the installation drawing included. An appropriately sized
circular opening in the vertical face of the sump has been drilled to 125#
ANSI B16.1 flat-face flange specifications. A full faced gasket and ap-
propriately sized bolts (by others) must be used for proper distribution.
11. Attach makeup water supply piping to appropriately sized float valve con-
nection located in cold water basin. Tower drain and overflow connections
are located on the side of the collection basin. If you wish to pipe overflow
and drain water to a remote discharge point, make those connections also.
12. Attach your warm water return piping to the inlet connection.

Fasteners and components provided by others that are to be attached

Note to the tower must be compatible with the cooling tower materials—e.g.
fasteners in a stainless steel cold water basin must be stainless steel.

Except for the horizontal components of piping, do not support your

Caution pipe from the tower inlet connection—support it externally.

Normally, one of the following two inlet arrangements is provided:

Bevel and groove distribution connection: This is a factory-installed,
galvanized pipe nipple, extending horizontally from the side of the tower.
It is both beveled for welding—and grooved for a mechanical coupling.
If a weld connection is used, it is recommended that the weld area be
protected against corrosion. Cold galvanizing is suggested, applied ac-
cording to the manufacturer’s instructions.

Protect adjacent areas from excessive heat and sparks during welding
Caution or damage could occur.

Flanged distribution connection: The spray system is fitted with a flat-

face flange connection that conforms to 125# ANSI B16.1 specifications.
A full faced gasket and appropriately sized bolts (by others) must be used
for proper distribution function.

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 installation

Motor Wiring
For maintenance/safety purposes, SPX recommends a lockout
Warning type disconnect switch for all mechanical equipment. In addition
to a disconnect switch, the motor should be wired to main power
supply through short circuit protection, and a magnetic starter with
overload protection.

Wire motor leads as shown on the motor nameplate matching the supply
voltage. Do not deviate from the motor nameplate wiring.
Internal space heaters may be present, depending upon the motor manufac-
turer. For space heater operation and wiring refer to the Marley “Fan Motor”
User Manual” User Manual Z0239042.
Either of following symbols may be shown on the motor nameplate –
Δ, Δ Δ, Y, or YY. These symbols represent how the motor is constructed on
the inside and in no way have anything to do with a Delta or Wye electrical
distribution system serving the motor.
When using a starter:
• Set motor overload protection to 110% of motor nameplate amps. This
setting allows the fan motor to operate during cooler weather. During
cooler weather it is common for the motor to draw 6 to 10% higher than
nameplate amps. High amps are common during tower commissioning
when the tower is dry and the ambient air temperature is cool.

Do not start the motor(s) more than four to five times per hour. Short
Note cycling the tower will cause fuses, breakers or O.L.s to operate and
will decrease motor life.

When using a two-speed starter:

• Motor rotation must be the same at slow speed and high speed.
• Single winding motor requires a starter with a shorting contactor.
• Two-winding motor requires a starter with out a shorting contactor.
• All two-speed starters must have a 20 second time delay relay when
switching from high speed to low speed.

Do not start the motor more than four to five times per hour (each
Note low speed start and each high speed start count as one start).

9
 installation

When using a VFD:

Before beginning, ensure that the motor is rated for “Inverter Duty”
Note per NEMA MG-1, part 31.

• Set the VFD solid state overload protection to 119% of motor nameplate
amps and set “maximum current parameter” in the VFD to motor nameplate
amps. “Maximum current parameter” will reduce fan speed and limit amp
draw to nameplate amps during cold weather operation. If furnished with
a mechanical O.L. set this at 110% over motor nameplate amps.
• Motor rotation must be the same in both VFD mode and By-pass mode.
• If cable distance between the VFD and motor is greater than 100 feet a DV/DT
output filter is recommended to avoid damage to the motor. 100 feet distance
is based on our field experience, the VFD manufacture may state different
distances and distance does vary depending on the VFD manufacture.
• Program the VFD for variable torque output.
• Do not start and stop the motor using the safety switch at the motor. If
the drive is being commanded to run and the load side is cycled ON and
OFF with the safety switch this may damage the VFD.

Using a VFD in cooling applications has advantages over traditional single

or two speed motor control. A VFD can reduce the cost of electrical energy
being used and provide better temperature control. In addition, it reduces the
mechanical and electrical stress on the motor and mechanical equipment.
Electrical savings can be large during periods of low ambient temperature
when the cooling requirement can be satisfied at reduced speeds. To benefit
from these advantages, it is important that the drive be installed correctly.
Marley supplies VFD and VFD controls specifically designed for our cooling
products. If you have purchased a Marley VFD and/or controls package, please
follow the instructions in the User Manual for that system. Most VFD problems
can be avoided by purchasing the Marley drive system. If you are installing a
VFD other than the Marley drive, please refer to that drives installation manual.

Improper use of a VFD may cause damage to equipment or personal

Warning injury. Failure to correctly install the VFD drive will automatically
void all warranties associated with the motor and any equipment
that is either electrically or mechanically (directly) attached to the
VFD drive system. The length of this warranty avoidance will be
contingent on properly installing the VFD system and repairing any
damage that may have occurred during its operation. SPX Cool-

10
 installation

ing Technologies does not assume responsibility for any technical

support or damages for problems associate with non-Marley brand
VFD systems.
Changing the operational fan speed from the factory settings could
cause the fan to operate in an unstable region which may result
in damage to the equipment and possible injury. Warranty is void
if the cooling tower is operated at speeds which cause damaging
vibrations to the cooling tower and associated equipment. When
utilizing a variable frequency drive, the cooling tower must be tested
across the full range of speeds and checked against CTI guidelines
for excessive vibration. Speed ranges not meeting these guidelines
must be locked out in the VFD.

Mechanical Equipment:
Always shut off electrical power to the fan motor prior to perform-
Warning ing any maintenance on the tower. Any electrical switches should
be locked out and tagged out to prevent others from turning the
power back on.

1. Spin the fan manually to assure that all fan blades properly clear the inside
of the fan cylinder. Observe the action of the sheaves and belts to be sure
that the motor is properly aligned with the fan sheave. If necessary, cor-
rect the alignment in accordance with the Belt Tensioning and Sheave
Alignment section on pages 21 and 24.

The following steps require operation of the fan motor while the access
Warning door is open. DO NOT view the fan operation from near or inside the
access door location. Fan rotation should be viewed from tower grade.

The access door should NOT be opened while the fan is operating.
Caution The fan rotation causes a negative pressure inside the cooling tower
and will abruptly pull the door open should access be attempted. Only
open the cooling tower access door when the fan is off and locked out.

2. Momentarily bump (energize) the motor and observe rotation of the fan.
The fan should rotate in a counterclockwise direction when viewed from
below. If rotation is backwards, shut off the fan and reverse two of the
three primary leads supplying power to the motor.

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 operation

If tower is equipped with a two-speed motor, check for proper rota-

Caution tion at both speeds. Check also to see that starter is equipped with a
20 second time delay which prevents direct switching from high
speed to low speed. If the fan is intended to be reversed for deicing
purposes, make sure that the starter is equipped with a 2 minute
time delay between changes of direction. These delays will prevent
abnormal stress from being applied to the mechanical equipment
and the electrical circuit components.

3. Run the motor and observe the operation of the mechanical equipment.
Operation should be stable.
4. Check belt tension and torque on the fan and motor sheave after 10 to
60 hours of operation. See Torque Values on page 25.

If the water supply system is not being operated—or if there is no

Note heat load on the system—motor amps read at this time may indicate
an apparent overload of as much as 10–20%. This is because of the
increased density of unheated air flowing through the fan. Deter-
mination of an accurate motor load should await the application of
the design heat load.

Tower Startup
Microorganisms including Legionella bacteria can exist in premise
Warning plumbing including cooling towers. The development of an effective
water management plan (WMP) and implementation of maintenance
procedures are essential to prevent the presence, dissemination and
amplification of Legionella bacteria and other waterborne contami-
nants throughout premise plumbing. Before operating the cooling
tower, the water management plan and maintenance procedures
must be in place and regularly practiced.

Water System:
1. Consult a knowledgeable water treatment professional to clean and treat
your new cooling tower prior to startup. Cooling towers must be cleaned
and disinfected regularly in accordance with ASHRAE Standard 188 and
Guideline 12.
The water conditions during the initial tower operation are crucial in pre-
venting premature corrosion of galvanized steel (white rust). For at least
the first eight weeks of operation, pH should be controlled between 6.5

12
 operation

and 8.0 with hardness and alkalinity levels between 100 and 300 ppm
(expressed as CaCO3).
2. Do NOT attempt any service unless the fan motor is locked out.
3. Remove any and all accumulated debris from tower. Pay particular atten-
tion to inside areas of cold water basin, louvers and drift eliminators. Make
sure that cold water suction screens are clear and properly installed.
4. Fill the water system to an approximate depth of 7" in the depressed area
of the cold water basin at the center of the tower. This is the recommended
operating water level. Adjust the float valve so that it is 75% open at that
level. Continue filling the system until the water reaches a level approxi-
mately 1⁄8" below the lip of the overflow.

If tower is equipped with a side or end suction connection, vent ac-

Note cumulated air from the top of the suction hood by removing one or
both tap screws provided at that location. Replace these tap screws
when venting is complete.

The system pumps and piping connected to the cooling tower must
Caution be configured such that the flowrate supplied to the water inlet of
each tower cell does not exceed the maximum design flowrate per
cell during startup, commissioning or operation. Overpumping will
result in elevated pressure levels in the tower’s water distribution
system - spray pressures exceeding 8.0 psi may damage the distri-
bution system.

5. Completely open all hot water flow control valves. Start your pump(s) and
observe system operation. Since the water system external to the tower
will have been filled only to the level achieved in the cold water basin, a
certain amount of “pump-down” of the basin water level will occur before
water completes the circuit and begins to fall from the fill. The amount
of initial pump-down may be insufficient to cause the float valve to open.
However, you can check its operation by pressing down on the operating
lever to which the stem of the float valve is attached.
Some trial and error adjustment of the float valve may be required to
balance the makeup water with tower operation. Ideally, the float valve
setting will be such that no water is wasted through the overflow at pump
shutdown. However, the water level after pump start-up must be deep
enough to assure positive pump suction.

13
 operation

6. Continue pump operation for about 15 minutes, after which it is recom-

mended that the water system be drained, flushed, and refilled.
7. While operating the condensing water pump(s) and prior to operating the
cooling tower fan, execute one of the two alternative biocidal treatment
programs described in the following:
• Resume treatment with the biocide which had been used prior to shut-
down. Utilize the services of the water treatment supplier. Maintain the
maximum recommended biocide residual (for the specific biocide) for
a sufficient period of time (residual and time will vary with the biocide)
to bring the system under good biological control
or
• Treat the system with sodium hypochlorite to a level of 4 to 5 ppm free
chlorine residual at a pH of 7.0 to 7.6. The chlorine residual must be
held at 4 to 5 ppm for six hours, measurable with standard commercial
water test kits.
If the cooling tower has been in operation and then shut down for a du-
ration of time and not drained, perform one of the two previous biocidal
treatment programs directly to the cooling water storage vessel (cooling
tower sump, drain down tank, etc.) without circulating stagnant water
over the cooling tower fill or operating the cooling tower fan.
After biocidal pretreatment has been successfully completed, cooling
water may be circulated over the tower fill with the fan off.
When biocidal treatment has been maintained at a satisfactory level for
at least six hours, the fan may be turned on and the system returned to
service. Resume the standard water treatment program, including biocidal
treatment.

14
operation

Tower Operation
General:
The cold water temperature obtained from an operating cooling tower will vary
with the following influences:
1. Heat load With the fan in full operation, if the heat load increases, the
cold water temperature will rise. If the heat load reduces, the cold water
temperature will reduce.
Note that the number of degrees (“range”) through which the tower cools
the water is established by the system heat load and the amount of water
being circulated, in accordance with the following formula:

Heat Load (Btu/hr)

Range – °F =
gpm x 500

or — in SI units
The cooling tower establishes only the cold water temperature attainable
Heat Load (kilowatts)
Range – °C
under any operating =
circumstance.
liters/sec x 4.187
2. Air wet-bulb temperature Cold water temperature will also vary with the
wet-bulb temperature of the air entering the louvered faces of the tower.
Reduced wet-bulb temperatures will result in colder water temperatures.
However, the cold water temperature will not vary to the same extent as
the wet-bulb. For example, a 20°F reduction in wet-bulb may result in only
a 15°F reduction in cold water temperature.
3. Water flow rate Increasing the water flow rate (gpm) will cause a slight
elevation in cold water temperature, while reducing the water flow rate
will cause the cold water temperature to decrease slightly. However, at
a given heat load (see formula above), water flow reductions also cause
an increase in the incoming hot water temperature. Use care to prevent
the hot water from exceeding 125°F, in order to prevent damage to the
tower components.
4. Air flow rate Reducing air flow through the tower causes the cold wa-
ter temperature to rise. This is the approved method by which to control
leaving water temperature.

15
 operation

If your tower is equipped with a single-speed motor, the motor may be

shut off when the water temperature becomes too cold. This will cause
the water temperature to rise. When the water temperature then becomes
too warm for your process, the motor can be restarted.

Fan Cycling Limits:

Considering the normal fan and motor sizes utilized on MD towers,

Note anticipate that approximately 4 to 5 starts per hour are allowable.

If your tower is equipped with a two-speed motor, you will enjoy greater
opportunity for temperature control. When the water temperature becomes
too cold, switching the fan to half-speed will cause the cold water tem-
perature to rise—stabilizing at a temperature a few degrees higher than
before. With a further reduction in water temperature, the fan may be
cycled alternately from half-speed to off.

Do not start the motor more than four to five times per hour (each
Note low speed start and each high speed start count as one start).

If your tower consists of two or more cells, cycling of motors may be

shared between cells, increasing your steps of operation accordingly.
Multicell towers equipped with two-speed motors will maximize energy
savings and minimize sound levels if fans are staged so that all fans are
brought up to low speed before any fan goes to high speed.

For greater insight on cold water temperature control, please read

“Cooling Tower Energy and its Management”, Technical Report
H-001, available on our website.

Freezing Weather Operation

During operation in subfreezing weather, the opportunity exists for ice to
form in the colder regions of the tower. Your primary concern is to prevent
the formation of destructive ice on the cooling tower fill air inlet and louvers.
Your understanding of cold weather operation will be enhanced if you read
Marley Technical Report H-003 “Cooling Towers and Freezing Weather”.

16
 operation

Slushy, transitory ice forms routinely in the colder regions of the fill
Note at low temperature. Such ice normally has no adverse effect on tower
operation, but its appearance should be a signal to the operator to
undertake ice control procedures. It is the operator's responsibil-
ity to prevent the formation of destructive (hard) ice on the cooling
tower fill and louvers. Certain guidelines should be followed:

1. Do not allow the tower’s leaving water temperature to drop below a mini-
mum allowable level—say 36°F to 40°F. If such low temperature operation
is necessary or beneficial to your process, establish the minimum allowable
level as follows:
During the coldest days of the first winter of operation, observe whether
any ice is forming on the bottom of the fill or the louvers. If hard ice is
present on either component, you must increase the allowable cold water
temperature. If the coldest possible water is beneficial to your process, ice
of a mushy consistency can be tolerated—but routine periodic observation
is advisable.

If the minimum allowable cold water temperature is established

Caution at or near minimum heat load, it should be safe for all operating
conditions.

Having established the minimum allowable cold water temperature,

maintaining that temperature can be accomplished by fan manipulation,
as outlined in Item 4 under Tower Operation. However, in towers of more
than one cell, where fans are manipulated sequentially, please realize
that the water temperature will be significantly lower in the cell or cells
operating at the highest fan speed than the net cold water temperature
produced by the entire tower would indicate. Wintertime operation of
multicell towers at low cold water temperature levels requires that the
operator be especially watchful.
2. Under extended extreme cold conditions, it may be necessary to operate
the fan in reverse. This forces warm air out through the louvers, melting
any accumulated ice—adequate heat load must be available. Reversal
of fan should only be done at half speed or less. Reverse operation of
the fan should be used sparingly and should only be used to control ice,
not to prevent it. Reverse fan operation should not need to exceed 1 or
2 minutes. Monitoring is required to determine the time required to melt
accumulated ice.

17
 operation

Operating the fan in reverse at half speed for prolonged periods

Warning during subfreezing weather can cause severe damage to fans and
fan cylinders. Ice can accumulate inside fan cylinders at fan blade
plane of rotation and fan blade tips will eventually strike this ring of
ice, damaging the fan blades or cylinder. Ice can also accumulate
on fan blades and be thrown off, damaging fan cylinder or blades.
Allow a minimum of 10 minute delay between reverse operation
and forward operation during subfreezing weather to permit ice to
dissipate from fan blades and fan cylinders. See Fan Drive Caution
note on page 12 for fan speed change and reversing precautions.

3. With no heat load on the circulating water, icing cannot be controlled

effectively by air control during freezing weather. Towers must not
be operated with reduced water rate and/or no heat load during
freezing weather. If the circulating water system cannot be shut down,
water returning from the process should be made to bypass the tower. If
a bypass is used, all water must be bypassed without modulation. If the
water bypass is directly into the tower's cold water basin, its design must
be approved by SPX Cooling Technologies.

Intermittent Freezing Weather Operation:

If periods of shutdown (nights, weekends, etc.) occur during freezing weather,
measures must be taken to prevent the water in the cold water basin—and all
exposed pipework—from freezing. Several methods are used to combat this,
including automatic basin heater systems available from Marley.

Unless some means of freeze prevention is incorporated into your

Warning system, the tower basin and exposed pipework should be drained
at the beginning of each wintertime shutdown period.
If tower basin is drained, verify that all basin heaters have been shut
off either by automatic cutoff or disconnect switch.

It is recommended that you discuss your freeze prevention options with your
local Marley sales representative.

18
 operation

Water Quality and Blowdown

Maintaining Water Quality:
The steel used in MD towers has been galvanized with a heavy zinc coating
averaging 2.0 mils in thickness. The MD stainless steel option is even more
corrosion resistant than galvanized steel in certain environments. Other ma-
terials used (PVC fill, drift eliminators, and louvers, aluminum fans, etc.) are
selected to offer maximum service life in a “normal” cooling tower environment,
defined as follows:
Circulating water with a pH between 6.5 and 8; a chloride content (as NaCl)
below 500 ppm; a sulfate content (SO4) below 250 ppm; total alkalinity (as
CaCO3) below 500 ppm; calcium hardness (as CaCO3) above 50 ppm; a
maximum inlet water temperature not to exceed 125°F; no significant con-
tamination with unusual chemicals or foreign substances; and adequate water
treatment to minimize scaling.
• Startup Conditions: The water conditions during the initial tower operation
are crucial in preventing premature corrosion of galvanized steel (white
rust). For at least the first eight weeks of operation, pH should be controlled
between 6.5 and 8.0 with hardness and alkalinity levels between 100 and
300 ppm (expressed as CaCO3).
• Chlorine (if used) shall be added intermittently, with a free residual not to
exceed 1 ppm—maintained for short periods. Excessive chlorine levels may
deteriorate sealants and other materials of construction.
• An atmosphere surrounding the tower no worse than “moderate industrial”,
where rainfall and fog are no more than slightly acid, and they do not contain
significant chlorides or hydrogen sulfide (H2S).
• Many proprietary chemicals exist for control of scale, corrosion, and biologi-
cal growth and should be used prudently. Also, combinations of chemicals
may cause reactions which reduce treatment effectiveness, and certain
chemicals such as surfactants, biodispersants and antifoams may increase
drift rate.

Unless you purchased a stainless steel MD, the structure of your MD

Note tower consists primarily of galvanized steel, therefore your water
treatment program must be compatible with zinc. In working with
your water treatment supplier, it is important that you recognize
the potential effects on zinc of the specific treatment program you
choose.

19
 operation

Blowdown:
A cooling tower cools water by continuously causing a portion of it to evaporate.
Although the water lost by evaporation is replenished by the makeup system, it
exits the tower as pure water—leaving behind its burden of dissolved solids to
concentrate in the remaining water. Given no means of control, this increasing
concentration of contaminants can reach a very high level.
In order to achieve water quality which is acceptable to the cooling tower (as
well as the remainder of your circulating water system), the selected water
treatment company must work from a relatively constant level of concentra-
tions. This stabilization of contaminant concentrations is usually accomplished
by blowdown, which is the constant discharge of a portion of the circulating
water to waste. As a rule, acceptable levels on which to base a treatment
schedule will be in the range of 2-4 concentrations. The following table shows
the minimum amount of blowdown (percent of flow) required to maintain dif-
ferent concentrations with various cooling ranges*:

Number of Concentrations
Cooling Range
1.5X 2.0X 2.5X 3.0X 4.0X 5.0X 6.0X
5° F (2.78° C) .78 .38 .25 .18 .11 .08 .06
10° F (5.56° C) 1.58 .78 .51 .38 .25 . 18 .14
15° F (8.33° C) 2.38 1.18 .78 .58 .38 . 28 .22
20° F (11.11° C) 3.18 1.58 1.05 .78 .51 .38 .30
25° F (13.89° C) 3.98 1.98 1.32 .98 .64 .48 .38
Multipliers are based on drift of 0.02% of the circulating water rate.

* Range = Difference between hot water temperature coming to tower and cold water tem-
perature leaving tower.

EXAMPLE: 700 gpm circulating rate, 18°F cooling range. To maintain 4

concentrations, the required blowdown is 0.458% or .00458 times 700 gpm,
which is 3.2 gpm.
If tower is operated at 4 concentrations, circulating water will contain four
times as much dissolved solid as the makeup water, assuming none of the
solids form scale or are otherwise removed from the system.

When water treatment chemicals are added, they should not be in-
Note troduced into the circulating water system via the cold water basin
of the cooling tower. Water velocities are lowest at that point, which
results in inadequate mixing.

20
 maintenance

Cooling Tower Inspection and Maintenance

Microorganisms including Legionella bacteria can exist in premise
Warning plumbing including cooling towers. The development of an effective
water management plan (WMP) and implementation of maintenance
procedures are essential to prevent the presence, dissemination and
amplification of Legionella bacteria and other waterborne contami-
nants throughout premise plumbing. Before operating the cooling
tower, the water management plan and maintenance procedures
must be in place and regularly practiced.

In addition, the following steps are recommended:

Do NOT attempt any service unless the fan motor is locked out.
• Consult a knowledgeable water treatment professional to clean and treat
your new cooling tower prior to startup. See Tower Startup section of this
manual.
• Cooling towers must be cleaned and disinfected regularly in accordance
with ASHRAE Standard 188 and Guideline 12.
• Workers performing decontamination procedures must wear personal
protective equipment (PPE) as directed by their facility safety officer.
• Cooling towers must be visually inspected regularly to assess signs of bacte-
rial growth, appearance of debris and scale on drift eliminators and general
operating conditions. Refer to ASHRAE Standard 188 and Guideline 12
for specific frequency recommendations.
• Replace worn or damaged components.
To minimize the presence of waterborne microorganisms, including Legionella,
follow the water management plan for your facility, perform regularly scheduled
cooling tower inspections and maintenance, and enlist the services of water
treatment professionals.
For additional technical support, contact your Marley sales represen-
tative. For help identifying the sales representative in your area, visit
spxcooling.com/replocator.

References:
ashrae.org. Search “ASHRAE Standard 188” and “ASHRAE Guideline 12.”
cdc.gov. Search “Water Management Program.”

21
 maintenance

Belt Tensioning:
Always shut off electrical power to the tower fan motor prior to
Warning performing any inspections that may involve physical contact with
the mechanical or electrical equipment in or on the tower. Lock out
and tag out any electrical switches to prevent others from turning
the power back on. Service personnel must wear proper personal
protective clothing and equipment.

On the MD5006 thru MD5010, the fan motor and belt adjustment mechanism
is located outside the tower. Remove the motor protection hood by loosening
the two thumbscrews on top and hinge the hood up and out of the way. Also,
remove the motor sheave safety bracket and set aside. See the following images.
On the MD5016 thru MD5018 the motor is located inside the tower plenum.
Open the access door (see Access Door Opening Procedure) and hinge out
of the way.
SAFETY
BRACKET

Any bolts removed functioning as mechanical or structural hardware

Caution should be replaced with the torques specified below.
Fastener Torque Values
Machine Bolt Galvanized Stainless
Size ft·lbƒ N·m ft·lbƒ N·m
8mm 8 10 15 20
10mm 15 20 30 40
12mm 25 35 50 65
16mm 65 85 120 160
20mm 125 170 230 315

Belt tension on all models is adjusted by turning a large threaded rod(s) that
drives the motor mounting plate away from (or toward) the fan centerline.

22
maintenance

To turn the rod(s), the

rod retention bracket(s)
must first be moved. On
the models with motors
located externally loosen
the thumbscrew holding
this bracket in place and
rotate the bracket away
from the assembly. On
models with the motor
located in the plenum
the rod retention is held in place with fasteners. Loosen fastener and slide
the bracket away from the adjusting rod. Turn the rod(s) clockwise to drive the
motor away from the fan (tighten belts)
or counterclockwise to drive the motor
toward the fan (loosen the belts). On
models with more than one rod, alternate
turns on the rods to prevent binding.
There is no need to loosen any other
hardware to adjust the belt tension. After
belt tension is adjusted to a satisfactory
position, install the rod retention bracket
with the thumbscrew and replace any
safety hoods.
Ideal tension is the lowest tension at
which the belt will not slip under peak load conditions. Check tension frequently
during the first 24-48 hours of run-in operation. Overtensioning shortens
belt and bearing life. Keep belts free from foreign material which may cause
slipping. Never apply belt dressing as this will damage the belt and cause

23
 maintenance
early failure. Specific tools are made to measure the tension of a V-belt drive
system. A Dodge® V-Belt Tension Tester, Browning® Belt Tension Checker
or equivalent an alternative should be used for tensioning V-belts. Check with
you local belt supplier.
Belt tension is measured by applying a force perpendicular to the belt at the
center point between motor and fan sheaves. The belt should deflect 1⁄64 of
the entire span, (measured sheave centerline to sheave centerline) when the
pressure shown in the table below is applied. Because belt tension is a func-
tion of the motor sheave diameter, it is necessary to inspect the motor sheave
to determine the diameter. If diameter markings are unreadable, measure the
sheave diameter at the bottom of the sheave grooves.
New belts (operating less than 8 hours) should be tensioned to the maximum
value. Tension after this period should use no less than the minimum value. If
the belt span was measured in inches, then use the pounds of force values.
If the belt span was measured in centimeters, then use the kilograms of force
values. If specific tensioning instructions are provided with your tensioning
tool, those instructions should be used instead.

Sheave Alignment:
Motor Sheave Used V-Belt New V-Belt
diameter minimum maximum
3.4" - 4.2" 4.9 lb 7.2 lb
85cm - 105cm 2.2 kg 3.3 kg
4.4" - 5.6" 7.1 lb 10.5 lb
106cm - 140cm 3.2 kg 4.8 kg
5.8" - 8.6" 8.5 lb 12.6 l
141cm - 220 cm 3.9 kg 5.7 kg

Always shut off electrical power to the tower fan motor prior to
Warning performing any inspections that may involve physical contact with
the mechanical or electrical equipment in or on the tower. Lock out
and tag out any electrical switches to prevent others from turning
the power back on. Service personnel must wear proper personal
protective clothing and equipment.
• The motor sheave is to be positioned as close as possible to the motor
in order to minimize torque on the motor bushings.
• The motor and fan sheaves may have grooves that are not used. The bot-
tom surface of the motor and fan sheaves must be aligned within 1⁄8" of

24
 maintenance

each other and level within 1⁄2° (1⁄8" in 12") in order to not adversely affect
belt and sheave life.
Sheave Assembly Bolt Torque
• Alignment can be achieved by placing a straight edge across the top of
Busing Type ft·lbƒ N·m
the sheaves making sure that it is level and measuring down to the bottom
SD 5 10 surface of both sheaves at four points. See photo.
SK 15 20
• The number of grooves on the motor and fan sheaves may not match
SF 25 30
each other, or the number of grooves on the belt. Always install the belts
E 35 50
on the highest grooves on the fan sheave. Doing so will reduce the force
on the fan shaft bearings, thus increasing their life.

Fan Motor Access and Removal:

Always shut off electrical power to the tower fan motor prior to
Warning performing any inspections that may involve physical contact with
the mechanical or electrical equipment in or on the tower. Lock out
and tag out any electrical switches to prevent others from turning
the power back on. Service personnel must wear proper personal
protective clothing and equipment.

The MD fan motors are located inside or

outside the cooling tower, depending on
the model. On MD5006 through MD5010
models, the fan motor is located outside the
cooling tower. The motor is fully accessed
by removing the motor protection hood.
Remove motor protection hood and the
drive belt by following the instructions in
the Belt Tensioning section.

25
 maintenance

MD5006 through MD5010 models’ fan motors are oriented with the shaft up.
The motor may be hoisted by threading an eye bolt into the motor shaft and
lifting with a hoist. To remove the motor fastener hardware, lift on the motor
slightly with the hoist to remove the weight from the fasteners, then loosen
and remove motor fasteners.
On MD5016 through MD5018 models, the fan motor is located inside the
plenum of the cooling tower. The motor can be accessed through the mechani-
cal access panel. See the Access Door Operation section for instruction on
opening the access panel. Remove the drive belt by following the instructions
in the Belt Tensioning section.
HINGE MOTOR MOUNT
HARDWARE RETAINING BOLTS
JACKING SCREW

ACCESS PANEL
OPENING

INSIDE VIEW

Motor inside plenum models are equipped with either a hinged or sliding
motor plate. For hinged motor plate models, loosen the motor mount system
retaining bolts shown in the image. It is not necessary to loosen any hard-
ware other than what is indicated. Hinge the motor mounting system 90° out
through the access panel. Attach a hoist to the motor with straps or chains.
Lift on the motor slightly with the hoist to remove the weight from the motor
fasteners, then loosen and remove motor fasteners.

Hoisting attachment locations vary by motor - choose strap or chain

Caution attachment locations carefully to provide a balanced lift.

For sliding motor plate models, the motor may be hoisted out through the fan
cylinder opening. Turn the adjustment rod(s) counterclockwise to slide the
motor toward the interior of the cooling tower. Remove the portion of the fan
guard nearest the motor location. It may be necessary to de-pitch or remove
one or more fan blades —consult the fan manual accompanying the cooling
tower. Attach a hoist to the motor with straps or chains. Lift on the motor

26
 maintenance
slightly with the hoist to remove the weight from the motor fasteners, then
loosen and remove motor fasteners.
If the motor is removed from the mounting plate, it should be reinstalled at the
torques specified—do not lubricate the bolts.
Motor Mounting Bolt Torque
Machine Bolt Galvanized Stainless
Size ft·lbƒ N·m ft·lbƒ N·m
10mm 15 20 30 40
12mm 25 35 50 65
16mm 65 85 120 160
20mm 125 170 230 315

Cold Water Basin Access / Air Inlet Louver Removal:

Some maintenance procedures require access to components located in the
cold water collection basin. All maintenance procedures can be performed
from the perimeter of the tower therefore there is no reason to enter basin.
To access the basin, one of the air inlet louver frames must be removed. To
remove, loosen the thumbscrews indicated in the image below and push the
louver retaining bracket up and to the left to move out of the way of the louver
frame. Tip the top of the frame out from the tower, then remove. Louver frames
are not the same size, if more than one louver frame is removed, the original
location should be noted.

Collection basin floor has uneven surfaces and has the potential to
Caution be slippery. Care should be taken if entering the basin.
Louver edges can be very sharp and could cut skin if proper protec-
tion is not used. Always wear gloves and sleeves when handling
louver packs.

27
 maintenance

Access Door Operation:

Always shut off electrical power to the tower fan motor prior to
Warning performing any inspections that may involve physical contact with
the mechanical or electrical equipment in or on the tower. Lock out
and tag out any electrical switches to prevent others from turning
the power back on. Service personnel must wear proper personal
protective clothing and equipment.

To allow access to the mechanical system, eliminators, water distribution

system and fill surface, a access door is provided toward the top of the tower.
To open, follow the following steps:
1. Remove any lock that is securing the door shut.
2. 
Loosen and remove the locking knob at the center of the access
door panel.
3. Slide the panel with the handle sideways as far as it will travel.
4. Push the panel toward the inside of the tower. The panel will hinge to the side.

Drift Eliminator Removal and Replacement:

The drift eliminators may be removed for cleaning, replacement or access to
the distribution system. The eliminators are held in place by a press fit, so there
is no need to remove any fasteners. However, eliminators are formed so that
they nest with each other and form a monolithic barrier. Individual packs of
eliminator are formed into 2'-0 wide sections that span from the casing wall
to the centerline of the tower, just under the mechanical torque tube.

Eliminator edges can be very sharp and could cut skin if proper
Caution protection is not used. Always wear gloves and sleeves when han-
dling eliminator packs.

28
 maintenance

Eliminators may be used as a walking surface for tower inspec-

Note tion and typical maintenance. For those instances of frequent or
prolonged servicing, it is necessary to protect the surface with
plywood or planking.

To remove the eliminator, stand inside the access panel and lift with two hands
on an eliminator section, this will indicate where one section stops and another
starts. Lift the eliminators at that intersection, removing two packs at one time
(see image). Once the first two packs are removed, the remaining packs should
be easily removed. Pay close attention to the orientation and placement, they
are not symmetrical. Each pack should be replaced at the location which it
was removed. Repeat this process for the second half of the tower.

Proper eliminator pack replacement is essential to tower operation.

Note Incorrect installation may result in excessive drift rates and fan
inefficiency! To ensure packs are reinstalled in the correct orienta-
tion, it is recommended that one pack is left in its original location
inside the tower as a reminder of pack orientation. Place packs in
the tower in the order they were removed. Packs should nest tightly
with each other, leaving a level surface with no gaps. The last two
packs should be installed at the same time. Place the final two
packs according to the image above, and push down to complete.

29
 maintenance
Distribution System Maintenance:
To keep your MD cooling tower operating at peak performance, it may be
necessary to clear the spray system of debris or sediment. To access the spray
system, remove the drift eliminators as explained in the previous section. Ob-
serve the spray system with full flow on the unit. Each nozzle should produce
a cone pattern spray which overlaps the adjacent nozzle patterns—see image.

Debris buildup in the nozzles, if left unchecked, may result in elevated

Caution pressure levels in the tower’s water distribution system. Spray
pressures exceeding 8.0 psi may damage the distribution system.

If a nozzle appears clogged or is not producing a cone pattern, remove the

nozzle and clean all surfaces. To remove the nozzle, pull down sharply on
the plastic component, leaving the rubber grommet seated in the PVC pipe.
Inspect the nozzle for cleanliness or broken
pieces. Each nozzle should have a turbula-
tor inside the outer shell—see image. If the
nozzle appears broken or damaged, consult
your Marley representative for replacement
parts. Insert the nozzles by pressing it back
into place inside the rubber grommet. It may
be necessary to wet the nozzle and grommet
to facilitate assembly.
Nozzles used with low-clog fill are attached
with a threaded connection for ease of re-
moval and cleaning. These nozzles have no
internal parts.

30
 maintenance

It may also be necessary to remove an entire branch arm from the spray sys-
tem. Each arm is held in place with a retention strap bolted to the branch arm
supports. Remove the bolts attaching the strap to the support and pull sharply
on the branch arm to disengage from the header box. It may be necessary to
rotate the branch arm while pulling out from the header box.
When branch arms are removed, access to the interior of the spray header
box is available to clean and remove any debris or sediment. A drain nozzle
at the centerline of the header box is intended to drain water from the system
at shutdown, as well as be removed to wash out the header box if necessary.
Be sure to replace this nozzle if removed.
Reinstall the branch arms to the header, engaging them far enough to align
the bolts of the tie down strap to the spray system supports. It may be neces-
sary to wet the rubber grommet and pipe to facilitate assembly. Ensure that
all nozzles are aligned to the bottom of the branch arm.

Schedule of Tower Maintenance:

Some procedures may require maintenance personnel to enter the tower.
Each cell has an access door for entry into the tower. All tower maintenance
can be performed from this location. An optional mechanical access platform
is designed and intended solely for personnel to gain access to the motor and
access door. Upon entering the tower, the eliminators and fill may be used as
a walking surface for tower inspection and typical maintenance. For those
instances of frequent or prolonged servicing, it is necessary to protect the
surface with plywood or planking. The fan deck and fan guard are not designed
as a walking or working surfaces. There are no maintenance procedures that
require access to top of the tower.

The purchaser or owner is responsible for providing a safe method

Warning for entering or exiting the access door.

Included with this instruction packet are separate User Manuals on each ma-
jor operating component of the tower, and it is recommended that you read
them thoroughly. Where discrepancies may exist, the separate User Manuals
will take precedence. The following is recommended as a minimum routine
of scheduled maintenance:

31
 maintenance

Always shut off electrical power to the tower fan motor prior to
Warning performing any inspections that may involve physical contact with
the mechanical or electrical equipment in or on the tower. Lock out
and tag out any electrical switches to prevent others from turning
the power back on. Service personnel must wear proper personal
protective clothing and equipment.

Weekly Visually inspect the cooling tower to assess general operating

conditions and for signs of microbial growth and appearance of debris,
scale and corrosion. Refer to ASHRAE Standard 188 and Guideline 12 for
specific frequency recommendations. Consult a knowledgeable water treat-
ment professional to maintain cooling tower hygiene.
Monthly (Weekly at start up) Observe, touch, and listen to the tower.
Become accustomed to its normal appearance, sound, and level of vibration.
Abnormal aspects relating to the rotating equipment should be considered
reason to shut down the tower until the problem can be located and corrected.
Observe operation of the motor, belt, sheaves and fan. Become familiar with
the normal operating temperature of the motor, as well as the sight and sound
of all components as a whole.
Inspect air inlet louvers, drift eliminators and basin trash screens and remove
any debris or scale which may have accumulated. Replace any damaged or
worn out components. Use of high-pressure water may damage the eliminator,
fill and louver material.
Observe operation of the float valve. Depress the operating lever to make
sure that the valve is operating freely. Inspect the suction screen for plugging.
Remove any debris that may have accumulated.
Check for any buildup of
silt on the floor of the cold
water basin. Mentally make
note of the amount, if any, so
future inspections will enable
you to determine the rate at
which it is forming.
View the water pattern as
it exits the fill section. Con-
sistent coverage indicates
that all nozzles are flowing
properly. If there are dry spot

32
 maintenance

in the fill or inconsistent coverage, this may be evidence of a clogged nozzle.

Inspect nozzles for blockage.
Every 3 months Lubricate fan shaft bearings. Each cell is equipped with
extended lube lines protruding through the casing adjacent to the access door.
While rotating equipment by hand, grease the bearings until a bead forms
around the seals—a maximum charge of 0.75 ounces is recommended. Mobil
SHC 460 grease is recommended.
Semi-Annually Check belt tension and condition. Adjust tensions as nec-
essary.
For those regions that require semi-annual fill removal and cleaning, remove
the fill through the fill access hatch (regional option) or the mechanical access
panel. Note the orientation and location of fill blocks. They must return into
the tower in the same location from which they were removed. Failure to do
so may result in diminished thermal capacity.
Annually Inspect the tower thoroughly, making maximum use of instructions
given in the separate user manuals. Check structural bolted connections and
tighten as required. Make preventive maintenance repairs as necessary.
Lubricate motor according to the manufacturer’s instructions. Motors with
sealed bearings do not require lubrication maintenance. Check to see that all
bolts are tight in the fan and mechanical equipment region, including the fan
cylinder and fan guard. Refer to Component User Manuals for torque values.

If the motor has sealed bearings, additional lubrication is not re-

Note quired. Refer to the motor nameplate to determine if grease type
and amount are specified.

Inspect the spray system and nozzles for any blockage. Nozzles can be re-
moved from the grommet by pulling sharply down on the nozzles. To replace
the nozzles, wet the surface of the nozzle and grommet and push nozzle back
into place.

33
 maintenance

Seasonal Shutdown Instructions

When the system is to be shut down for an extended period of time, it is
recommended that the entire system—cooling tower, system piping, heat
exchangers, etc.—be drained. Leave the basin drains open.
During shutdown, follow recommendations in the Cooling Tower Inspec-
tion and Maintenance section of this manual before attempting repairs. Pay
particular attention to mechanical equipment supports.
Following each year’s shutdown and cleaning, inspect the tower’s metal surfaces
for evidence of the need to apply a protective coating. Do not misinterpret
grime and transient rust from the piping system as a need to have the tower
painted. If relatively bright metal can be exposed by cleaning, consider that
the galvanizing has remained effective. Unless there is evidence of a general-
ized failure of the galvanizing, localized touch-up should be all that is required.

To the extent that the galvanizing (zinc coating) still exists, paint
Note will not adhere to it readily. Contact the manufacturer of the coating
you intend to use for instructions.

Tower framework Check casing and structural bolted connections and

tighten as required.
Fan Check fan assembly bolting and tighten as required. Use torque values
prescribed in the Fan User Manual.
Fan shaft bearings Lubricate fan shaft bearings at close of each operating
season—see page 33.
Clean and lubricate motor at close of each operating season (refer to motor
manufacturer’s recommendations.) Check motor anchor bolts and tighten as
required.

Do not start motor before determining that there will be no interfer-

Warning ence with free rotation of the fan drive.

The motor should be operated for three hours at least once a month. This
serves to dry out windings and lubricate bearing surfaces (refer to Marley
“Fan Motor” User Manual User Manual Z0239042.
At start of new operating season, make sure bearings are adequately lubricated
before returning motor to service. Does not apply to motors with sealed bearings.

34
maintenance

Prolonged Shutdown:
If shutdown period is longer than seasonal, contact your Marley sales repre-
sentative for additional information.

SPX Cooling Technologies Services

Our interest in your MD cooling tower does not end with the sale. Having
conceived, designed, and manufactured the most reliable and longest-lasting
cooling tower of its class, we want to make sure that you gain the maximum
possible benefit from its purchase.
Therefore, the following services are available which are intended to: assure
the maximum possible service life under your operating conditions; tailor the
operating characteristics to your specific needs; and maintain consistently
optimum thermal performance capability. They are available by contacting
your Marley sales representative.
Replacement parts A complete stock of parts and components is maintained
at one or more of the various Marley plants. In cases of emergency, they can
normally be shipped within 24 hours—by air freight if necessary. However, you
would obviously benefit from anticipating your need in advance, thus avoiding
the cost of special handling.
Be sure to mention your tower serial number (from the tower nameplate) when
ordering parts.
Periodic maintenance You may wish to contract with SPX for regularly
scheduled visits—for the purpose of inspecting and reporting your tower’s
condition—to make recommendations intended to prevent emergencies— and
to perform maintenance considered outside the norm.
This service is not intended to replace the important function performed by
your maintenance staff. Their attention assures the tower’s routine operating
performance, and is invaluable. However, we recognize the unusual manner
in which a cooling tower performs its function—as well as the unique forces
which act upon it—may be considerations which occasionally require the
services of an expert technician.

35
 additional information

Increased load requirements MD towers are designed so that cells of

either equal or unequal capacity can be added in the future. This allows you to
compensate for the load increases that normally occur with the replacement
or addition of production equipment—and still retain continuity with respect
to your cooling tower system.
Tower rebuilding SPX Cooling Technologies routinely rebuilds and upgrades
cooling towers of all materials and manufacture. If your tower ever reaches the
limit of its service life, we recommend that you investigate the cost of rebuild-
ing before you routinely order a new replacement tower.
Each MD tower includes a document package containing general
orientation drawings, “MD Field Installation Manual” Assembly Instructions,
and tower component manuals. These documents contain important
information relating to safe installation and operation of the cooling
tower. Field installation is always required for fan guards, piping inlets and
piping outlets. Some optional accessories, such as valves, handrails, ladders
and safety cages may also require field installation. If installation details are
not covered in the “MD Field Installation Manual” a separate installation
drawing or manual for each purchased option is included in the document
package along with bills of material. If you have purchased an option and
can’t find the appropriate installation drawing, contact your local Marley sales
representative before proceeding.
In addition to these specific documents, SPX publishes numerous technical
reports including more detailed information on a variety of cooling tower op-
eration and service topics. Your Marley sales representative will be happy to
give you copies of these reports at no charge.
For complete parts and service assistance, contact the Marley sales repre-
sentative in your area. If you need help locating the office nearest you, please
phone 913 664 7400 or check the internet at spxcooling.com.

36
maintenance schedule
Maintenance Service Monthly Semi-annually Seasonal Startup or Annually
Inspect General Condition and Operation x x

Observe Operation of:

Mechanical–motor, fan and drive mechanism x x

Makeup valve (if equipped) x x

Inspect for unusual noise or vibration x x

Inspect and Clean:

Air inlet x x

PVC drift eliminators x x

Nozzles x x

Fan motor exterior x x

Collection basin x x

Check:

Collection water basin level x x

Blowdown–adjust as required x x

Geareducer Drive (if equipped):

Check for loose fasteners including oil drain plug x

Check oil level, check for / repair oil leaks x x

Change oil R

Make sure vent is open x x

Check driveshaft or coupling alignment x

Check for loose driveshaft or coupling fasteners x

Check driveshaft or coupling bushings or flex element for unusual wear x x

Lube lines (if equipped):

Check for oil leaks in hoses or fittings x R x

Belt drive:

Fan shaft bearing lubrication (every 3 mo.) every 3 months every 3 months

Check and tighten support fasteners x

Check shaft, sheave and belt alignment x

Check belt tension and condition x x

Check sheave bushing fastener torque x

Fan:

Check and tighten blade and hub fasteners x

Check fan blade pitch and tip clearance x

Check fan cylinder for loose fasteners x

Motor:

Lubricate (if required) R

Check mounting bolts for tightness x

Operate at least 3 hours a month 3 hours a month 3 hours a month

Basin Heater (if equipped):

Check for proper operation of temp/low water level sensor x

Inspect/clean buildup of contaminant from sensor x x

Structure:

Inspect/tighten all fasteners x x

Inspect and touch up all metal surfaces x

R — Refer to Component User Manual

Note: It is recommended at least weekly, that the general operation and condition be observed. Pay attention to
any changes in sound or vibration that may signify a need for closer inspection.

37
troubleshooting

Trouble Cause Remedy

Check power at starter. Correct any bad connections between the
control apparatus and the motor.
Power not available at motor Check starter contacts and control circuit. Reset overloads, close
terminals contacts, reset tripped switches or replace failed control switches.
If power is not on all leads at starter, make sure overload and short
circuit devices are in proper condition.

Motor will not start Wrong connections Check motor and control connections against wiring diagrams.
Check nameplate voltage against power supply. Check voltage at
Low voltage
motor terminals.
Open circuit in motor winding Check stator windings for open circuits.
Disconnect motor from load and check motor and Geareducer for
Fan drive stuck
cause of problem.
Rotor defective Look for broken bars or rings.
Stop motor and attempt to start it. Motor will not start if single phased.
Motor running single-phase
Check wiring, controls and motor.
Motor leads connected incorrectly Check motor connections against wiring diagram on motor.
Bad bearings Check lubrication. Replace bad bearings.
Unusual motor noise
Electrical unbalance Check voltages and currents of all three lines. Correct if required.
Air gap not uniform Check and correct bracket fits or bearing.
Rotor unbalance Rebalance.
Cooling fan hitting end bell-guard Reinstall or replace fan
Wrong voltage or unbalanced Check voltage and current of all three lines against nameplate values.
voltage
Check fan blade pitch. See Fan User Manual. Check for drag in fan
Overload
drivetrain as from damaged bearings.
Check nameplate against power supply. Check RPM of motor and gear
Wrong motor RPM
ratio.
Remove grease reliefs. Run motor up to speed to purge excessive
Bearings over greased
grease. Does not apply to motors with sealed bearings.
Wrong lubrication in bearings Change to proper lubricant. See motor manufacturer’s instructions.
Stop motor and attempt to start it. Motor will not start if single phased.
One phase open
Check wiring controls and motor
Motor runs hot Clean motor and check ventilation openings. Allow ample ventilation
Poor ventilation
around motor.
Winding fault Check with Ohmmeter.
Bent motor shaft Straighten or replace shaft.
Remove plugs and regrease bearings. Does not apply to motors with
Insufficient grease
sealed bearings.
Limit cumulative acceleration time to a total of 30 seconds per hour.
Too frequent starting or speed
Set on/off or speed change set-points farther apart. Consider installing
changes
a Marley VFD for fine temperature control.
Deterioration of grease or foreign Flush bearings and relubricate. Does not apply to motors with sealed
material in grease bearings.
Bearings damaged Replace bearings.

38
troubleshooting

Trouble Cause Remedy

Check transformer and setting of taps. Use higher voltage on
Voltage too low at motor
transformer terminals or reduce loads. Increase wire size or reduce
Motor does not come up to terminals because of line drop
inertia.
speed
Look for cracks near the rings. A new rotor may be required. Have
Broken rotor bars
motor service person check motor.
Wrong motor rotation Wrong sequence of phases Switch any two of the three motor leads.
If new, see if noise disappears after one week of operation. Drain, flush
Geareducer bearings and refill Geareducer oil. See Geareducer User Manual. If still noisy,
Geareducer noise replace.
Correct tooth engagement. Replace badly worn gears. Replace gears
Gears
with broken or damaged teeth
Tighten all bolts and cap screws on all mechanical equipment and
Loose bolts and cap screws
supports.
Make sure motor and Geareducer shafts are in proper alignment and
Unbalanced driveshaft or worn “match marks” properly matched. Repair or replace worn couplings.
couplings Rebalance driveshaft by adding of removing weights from balancing
cap screws. See Driveshaft User Manual.

Unusual fan drive vibration Make certain all blades are as far from center of fan as safety devices
Fan permit. All blades must be pitched the same. See Fan User Manual.
Clean off deposit build-up on blades
Worn Geareducer bearings Check fan and pinion shaft endplay. Replace bearings as necessary.
Disconnect load and operate motor. If motor still vibrates, rebalance
Unbalanced motor
motor.
Bent Geareducer shaft Check fan and pinion shaft with dial indicator. Replace if necessary.
Blade rubbing inside of fan
Adjust cylinder to provide blade tip clearance.
Fan noise cylinder
Loose bolts in blade clamps Check and tighten if necessary
Insufficient blowdown See “Water Treatment” section of this manual.
Scale or foreign substance in
circulating water system Consult competent water treating specialist. See “Water Treatment”
Water treatment deficiency
section of this manual.
Check to see if local heat sources are affecting tower. See if
Entering wet-bulb temperature
surrounding structures are causing recircuation of tower discharge air.
is above design
Discuss remedy with Marley representative.
Design wet-bulb temperature May have to increase tower size. Discuss remedy with Marley
was too low representative.
Cold-water temperature too
Actual process load greater May have to increase tower size. Discuss remedy with Marley
warm
than design representative.
(see “Tower Operation”)
Overpumping Reduce water flow over tower to design conditions.
Check motor current and voltage to be sure of correct contract power.
Repitch fan blades if necessary. Clean louvers, fill and eliminators.
Tower starved for air
Check to see if nearby structure or enclosing walls are obstructing
normal airflow to tower. Discuss remedy with Marley representative.
Spray system malfunction Inspect spray system for proper operation. Correct as necessary.
Excessive drift exiting tower Check to see that the eliminators are clean, free of debris and installed correctly.
Faulty drift elimination
Clean if necessary. Replace damaged or worn out components.

39
 MD cooling tower
U S E R M A N UA L

SPX COOLING TECHNOLOGIES, INC.

7401 WEST 129 STREET Z0602117_G | ISSUED 04/2019
OVERLAND PARK, KS 66213 USA ©2010-2019 SPX COOLING TECHNOLOGIES, INC. ALL RIGHTS RESERVED
913 664 7400 | spxcooling@spx.com In the interest of technological progress, all products are subject to design
spxcooling.com and/or material change without notice.