Maintenance

Instructions

COOLING TOWERS, CLOSED CIRCUIT COOLERS

EVAPORATIVE CONDENSERS

KTI – Plersch Kältetechnik GmbH

Carl-Otto-Weg 14/2
88481 Balzheim – Unterbalzheim/Germany
Tel: 07347-9572-0
Fax: 07347-9572-22
E-mail: ice@kti-plersch.com
Internet: www.kti-plersch.com

VIP – Various Ice Products FZE

Jebel Ali Free Zone

RA 08 MB 04 (new blue sheds)
P.O. Box 17618, Dubai, U.A.E
Tel: 00971-4-8834774
Fax: 00971-4-8834779
E-mail: vip@vipdubai.ae
Cooling Towers, Closed Circuit Coolers & Evaporative Condensers

Introduction Any water treatment system used in the unit must be

compatible with the unit’s materials of construction. Although
Congratulations on the purchase of your EVAPCO evaporative
high quality galvanized steel is used in most units, alternate
cooling unit. EVAPCO equipment is constructed of the
materials of construction such as stainless steel and fiberglass
highest quality materials and designed to provide years of
are available as options.
reliable service when properly maintained.
Evaporative cooling equipment is often remotely located and If a chemical water treatment system is used, the chemicals
periodic maintenance checks are often overlooked. It is selected must be accurately metered and concentrations
important to establish a regular maintenance program and be properly controlled. See Table 1 for recommended levels.
sure that the program is followed. A clean and properly Soft water systems should be avoided.
serviced unit will provide a long service life and operate at
The use of acid should be avoided. If acid cleaning is
peak efficiency.
required, only inhibited acids recommended for use with
ATTENTION galvanized steel should be used.
? Before carrying out any operation, turn off the power
supply to all electrical parts presenr on the unit. Caution - Never batch load chemicals into unit.
? For any work to be carried out on top of the unit, use
Always regulate chemical feed.
ladders, protection and adequate safety measures
against the risk of a fall, in accordance with safety
requirements of the country in question.
? During maintenance operations, the worker must use Parameter Range
personal precautions (gloves, helmet, masks, etc.) as
prescribed by the country in question. pH 6.5 to 8.0*

Recirculated Water System Hardness as CaCO3 50 to 300 ppm

Evaporative cooling equipment rejects heat by evaporating a Alkalinity as CaCO3 50 to 300 ppm
portion of the recirculated water spray and discharging it from
the unit with the hot, saturated air. As the spray water Chlorides as Cl <125 ppm
evaporates, it leaves behind the mineral content and
impurities of the supply water. If these residuals are not * Galvanized steel units may require routine
purged from the water distribution system, they will become passivation when operating with a pH of 8.3 or
concentrated and lead to scaling, corrosion, sludge build-up higher in order to prevent “white rust.”
and biological fouling.
Table 1 - Recommended Water Chemistry
To avoid build-up of residuals in the water distribution system,
water must be bled off from the system in an amount equal to
the rate of evaporation. In addition, water quality should be Control of Biological Contamination
checked to ensure that the chemistry is balanced and that the
water system is free from biological contamination. Water quality should be checked regularly for biologcal
contamination. If biological contamination is detected, a more
aggressive water treatment and mechanical cleaning program
Bleed off is required. The water treatment program should be
Evaporative condensers and closed circuit coolers are performed in conjunction with a qualified water treatment
normally supplied with a pump assembly on the side of the company. It is important that all internal surfaces be kept
unit which incorporates a bleed line and valve. It is clean of accumulated dirt and sludge. In addition, the drift
recommended that the bleed valve on these units be opened eliminators should be kept in good operating condition.
fully to guarantee sufficient bleed volume. If the make-up To minimize the risk of biological contamination, at initial
water is is relatively free of impurities, it may be possible to start-up or after an extended shut down, it is
decrease the bleed, but the unit must be checked periodically recommended that the entire system (cooling tower,
to make sure that no scale forms and that the water chemistry system piping, heat exchanger, etc.) be properly treated.
remains balanced. Clean all debris such as leaves and dirt from the unit.
Open cooling towers and coil products supplied without pumps Completely fill the basin to the overflow level with fresh
need to have a bleed line installed on the discharge side of the water. Initiate a biocide water treatment or shock
system pump. A metering connection and globe valve should treatment program prior to operating the unit. It is
also be provided. The metering connection is used to preferable that all such procedures be conducted or
determine the bleed water volume. The globe valve is used to supervised by your water treatment specialist.
regulate flow. The bleed line and valve should be large
enough to allow bleed off of an amount of water equal to Air Contamination
1,6 (l/hr) x capacity (kW).
If the unit is located in an industrial area where there are
chemical fumes, the impurities in the air will be washed out in
the recirculated water and may cause scaling or corrosion. It
Water Treatment is important not to locate the unit next to a smokestack
In some cases, the make-up water will be so high in mineral because the unit will draw in these fumes and severely
content that a normal bleed-off will not prevent scaling. Water corrosive conditions may result. Bleed-off will help the
treatment will be required and a qualified water treatment situation, but if there is any sign of corrosion or scaling, a
company familiar with the local water conditions should be qualified water treatment company should be contacted.
consulted. 2
Cooling Towers, Closed Circuit Coolers & Evaporative Condensers

Routine Maintenance of the Recirculated Model Number Operating

Water System Level
ICT 4-54 through 4-912 180 mm
ATTENTION
Before carrying out this operation, clear the tension to the SST/UBT 8-56B through 24-918B 230 mm
fan motor. SST/UBT 24-524B through 24-936B 280 mm

1. Strainer AT 8-56D through 24-918D 230 mm

AT 24-524D through 24-936D 280 mm
The pan strainer should be removed and cleaned weekly or as AT 19-56 through 224-918 230 mm
often as necessary to keep it clean. AT 424-024 through 428-948 280 mm

2. Pan KT 14-024 through 28-924 280 mm

The pan should be flushed out monthly or as often as necessary REP 217-111 through 224-918 230 mm
to keep down any accumulation of dirt.
LSTA 4-61 through 4-126 360 mm
3. Water Make-Up LSTA 5-121 through 5-187 230 mm
LSTA 8P-121 through 8P-365 230 mm
The float and float valve should be checked monthly to make LSTA 10-121 through 10-366 330 mm
sure that the water level is correct. See Table 2.
LRT 3-61 through 8-128 200 mm
At initial start-up or after the unit has been drained, the unit must
be filled to overflow. Overflow is above the normal operating EDX 212-0122 through 214-1524 330 mm
level and accommodates the volume of water normally in
suspension and in the water distribution system. ATW/UBW 22 through 45 220 mm
ATW/UBW 68 through 432 300 mm
The water level should always be above the strainer and ATW/UBW 576 through 864 340 mm
pump suction. Check by running the pump with the fans off and
observing the water level through the access door. Maintain LSWA 20 through 30 260 mm
make-up water pressure between 140 and 340 kPa. LSWA 41 through 87 320 mm
LSWA 116 through 348 450 mm
4. Pressurized Water Distribution Systems - LSWA P91 through P270 360 mm
(Forced Draft and Counter-Flow Induced Draft)
LRW 18 through 96 200 mm
Check the water distribution system monthly to make sure it is
operating properly. On forced draft models, remove one or two PMWA 116 through 348 450 mm
eliminator sections from the top of the unit and observe the
LSCB 36 through 120 260 mm
operation of the water distribution system. On induced draft
LSCB 135 through 385 320 mm
models (except direct drive) lifting handles are provided along LSCB 400 through 1610 450 mm
the top layer of eliminators. These can be easily removed from LSCB 281 through 1120 360 mm
the access door and the distribution system observed. Always
check the spray system with the pump on and the fans off. The LRC 25 through 379 200 mm
diffusers are essentially non-clogging and should seldom need
cleaning or maintenance. ATC 50 through 165 220 mm
ATC 180 through 435P 300 mm
If the water diffusers are not functioning properly, it is a sign that ATC 420 through 1690 300 mm
the pan strainer has not been working properly and that foreign ATC 1735 through 3225 350 mm
matter or dirt have accumulated in the water distribution pipes.
The nozzles can be cleared by taking a small pointed probed UBC 180 through 3225 280 mm
and moving it rapidly back and forth in the diffuser opening with
PMCB 175 through 375 320 mm
the pumps running and the cooling load and fans off. PMCB 290 through 1550 450 mm
If an extreme build-up of dirt or foreign matter occurs, remove PMCB 435 through 1770 450 mm
the end cap last two nozzles in each branch to flush the debris
from the header pipe. The branches or header can be removed
for cleaning, but do so only if necessary. Check the strainer in
Table 2 - Recommended Operating Water Level
the pan to make sure it is in good condition and positioned
properly so that cavitation or air entrainment does not take
place. When inspecting and cleaning the water distribution
system, always check that the orientation of the water diffusers
is correct as shown below.

Figure 1 - Water Diffuser Orientation

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Cooling Towers, Closed Circuit Coolers & Evaporative Condensers

5. Gravity Feed Water Distribution Systems -

(Cross-Flow Induced Draft)
Cross-flow cooling towers use a gravity-feed distribution
system. Hot water is pumped into distribution pans and is
drained by gravity through a matrix of diffusers heads. The
hot-water distribution pans and diffusers are accessed from
the top of the unit by sliding back the FRP pan cover. The
top of the anti-vortex type diffuser can be pulled off if
necessary, allowing debris to be removed. The lower body of
the diffuser can be removed by turning and pulling.

6. Bleed-Off Valve
The bleed-off valve, whether factory or field installed, must be
checked weekly to make sure it is functioning and set
properly. Keep the bleed-off valve wide open unless it has
been determined that it can be set partially open without
causing scaling or corrosion. Figure 4 - Drift Eliminators on 1,2 and 1.5 m Wide LS Units

7. Pump (When Supplied)

The pump and pump motor should be lubricated and serviced
in accordance with the pump manufacturer’s instructions as
supplied with the unit.

Drift Eliminators
Figure 2 shows the direction of discharge from the drift
eliminators. Figures 3, 4 and 5 show the proper orientation
for drift eliminators on LR and LS series units. Drift
eliminators must be correctly replaced whenever they are
removed during service. Improperly oriented drift eliminators
may lead to recirculation. Orientation is not critical on
induced draft units.

Figure 5 - Drift Eliminators on 2.4, 3.0 and 3.6 m Wide LS Units

Freeze Protection
The simplest and most effective way of keeping the
recirculated water from freezing is to use a remote sump.
With a remote sump, the recirculating water pump is mounted
remotely at the sump and whenever the pump is shut off, all
Figure 2 - Air Discharge from Drift Eliminators recirculating water drains back to the sump.
Recommendations for sizing the remote sump and
recirculating water pumps for coil products are presented in
their respective catalog bulletins. Contact your local EVAPCO
representative for sizing remote sumps for cooling towers.
If a remote sump cannot be used, pan heaters are available.
Either electric heaters, hot water coils, steam coils or steam
injectors may be used to heat the basin water when the unit is
shut down. However, the basin heater will not prevent the
external water lines, pump or pump piping from freezing. The
make-up water supply , overflow and drain lines, as well as
the pump and pump piping up to the overflow level must be
heat traced and insulated to protect them from damage.
A condenser or cooler cannot be operated dry (fans on, pump
off) unless the water is completely drained from the pan. The
pan heaters are sized to prevent pan water from freezing only
when the unit is completely shut down.
Figure 3 - Drift Eliminators on LR Units

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Cooling Towers, Closed Circuit Coolers & Evaporative Condensers

Fan System Oil Drippage may result from over-oiling or from using too light
an oil. Should this condition persist with correct oiling, it is
recommended that the next heavier weight oil be used.
The fan systems of both centrifugal and propeller-driven
units are rugged and should require minimal attention. All bearings used on EVAPCO equipment are factory adjusted
However, the fan system should be checked regularly and and self-aligning. Do not disturb bearing alignment by
lubricated at the proper intervals. The following maintenance tightening the sleeve bearing cap bolts.
schedule is recommended.
Motor Bearings
Fan Shaft Ball Bearings EVAPCO uses only totally enclosed motors. Air over type
Lubricate the fan shaft ball bearings every 1000 hours or motors (TEAO) have sealed bearings and do not require
every 3 months on induced draft units. Lubricate the fan lubrication. Fan cooled motors (TEFC) require periodic
shaft ball bearings every 2000 hours or every 6 months on lubrication. For these motors, please follow the guidlines
forced draft units. Use any of the following waterproof, given in the motor manufacturer’s maintenance instructions.
inhibited greases which are suitable for operation between
- 40 °C and 120 °C. Fan Drives
Mobil - SHC 32 The fan belt tension should be checked at start-up and again
Chevron - SRI after the first 24 hours of operation to correct for any initial
American - Rycon Premium stretch. On externally mounted belt-drive units, both J-type
Shell - Alvania 3 adjustment bolts on the motor base should have an equal
or similar amount of exposed thread for proper sheave and belt
Feed grease slowly or bearings seals may be damaged. alignment. To check belt alignment on units with externally
mounted motors, measure the distance from the motor base to
Most units are supplied with extended grease lines to allow the J-bolt mounting angles to ensure that both sides of the
easy lubrication of fan shaft bearings. Induced draft units up base are located the same distance from the unit. This should
to 2.4 m wide with belt driven fans have extended lube ensure that the sheaves are properly aligned since sheaves
fittings beside the fan casing access door. 3.6 and 7.2 m will have been pre-set at the factory. As a final check, lay a
wide induced draft units have extended lube fittings located straight-edge from sheave to sheave. There should be four-
just inside the fan casing access door on the support rail. All point contact between the sheaves and the straight-edge.
large LS and PM series forc ed draft units have extended Adjust the position of the motor sheave if necessary.
lube fittings at the front of the unit. LR series units have
extended lube lines located at the side of the unit. Removal Proper belt tension can be determined by pressing the belt
of fan screens is not necessary on forced draft units with with one finger about midway between the sheaves using
extended lube lines. moderate pressure. The belt should deflect about 20 mm on
induced draft models and 13 mm on forced draft models.
Check belt tension on a monthly basis.
Fan Shaft Sleeve Bearings
(1.2 m wide LS series units only) On 3.6 and 7.2 m wide units with internally mounted motors,
the motor base and adjusting screw should be lubricated with
Lubricate the intermediate sleeve bearing(s) with the oil
a high quality waterproof grease on an annual basis.
provided in the rigging pack before start-up. The reservoir
should be checked several times during the first week to On 3.0 and 3.6 m wide vane-axial fan models and on LR
ensure that the oil reserve is brought up to full capacity. models, a motor adjustment tool is provided to facilitate belt
After the first week of operation, lubricate the bearing(s) tensioning. The tool will be found threaded onto one of the
every 1000 hours or every 3 months. High temperatures or motor adjustment all threads. To use, unthread and invert the
poor environmental conditions may necessitate more tool, placing the hex end over the locknut. Tension the belts
frequent lubrication. The oil reservoir consists of a large felt- by turning the nut on the underside of the motor plate
packed cavity within the bearing. It is not necessary to counterclockwise. When the belts are properly tensioned,
maintain the oil level within the filler cup. tighten the locknut.
Use one of the f ollowing industrial grade, non-detergent
mineral oils. Do not use a detergent based oil or those Gear Drives
designated heavy-duty or compounded. Different oils Induced draft units with gear drive systems require special
may be required when operating at temperatures below maintenance. Please refer to the gear manufacturer’s
-1°C continuously. Table 3 gives a short list of approved recommended maintenance instructions. These will be
lubricants for each temperature range. Most automotive enclosed and shipped with the unit.
oils are detergent based and may not be used.
Air Inlet
Ambient Temp Texaco Drydene Exxon
Inspect the air inlet louvers (induced draft units) or fans
-1°C to 38°C Regal R&O 220 Paradene 220 Terrestic 220 (forced draft units) monthly to remove any paper, leaves or
other debris that may be blocking airflow into the unit.
-32°C to -1°C Capella WF 32 Refrig. Oil 3G ——————

Table 3 - Sleeve Bearing Lubricants

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Cooling Towers, Closed Circuit Coolers & Evaporative Condensers

Basin and Casing Materials Freeze Protection of Closed Circuit

Clean and inspect the basin and casing materials inside and Fluid Cooler Coils
out once each year.
The simplest and most effective way of protecting the heat
exchanger coil from freezing is to use an inhibited ethylene
Galvanized Steel Construction glycol anti-freeze. If this is not possible, an auxiliary heat load
Heavy mill galvanizing provides an excellent corrosion must be maintained on the coil at all times so that the water
resistant barrier for the substrate steel on an evaporative temperature does not drop below 10°C when the cooler is
cooling unit. The zinc finish is a reactive metal which acts as shut down. A minimum recommended flow rate should also
a sacrificial anode to protect the steel substrate. Units that be maintained. See Table 4.
are operated within the recommended pH levels of 6.5 to 8.0 If an anti-freeze solution is not used, the coil must be drained
allow a surface barrier of non-porous zinc carbonate and zinc immediately whenever the pumps are shut down or flow stops.
hydroxide to form which prevents rapid galvanic corrosion. This is accomplished by automatic drain valves and air vents
This basic zinc carbonate barrier must be allowed to form in in the piping to and from the cooler. Care must be taken to
order to provide maximum protection for the mill galvanized ensure that the piping is adequately insulated and sized to
steel. allow the water to flow quickly from the coil. This method of
In recent years, some evaporative cooling systems have protection should be used only in emergency situations and is
experienced a phenomenon which results in the rapid neither a practical nor recommended method of freeze
formation of non-protective zinc carbonate cells. These protection. Coils should not be drained for an extended period
deposits appear as white powdery cells and are considered to of time.
be a zinc corrosion by-product. Since the cells are porous, When the unit is in operation during freezing weather, some
they will allow continued corrosion of the non-passivated type of capacity control is normally required in order to keep
galvanized surface. This type of corrosion is usually found in water temperatures from dropping below 10°C. Operating dry
the wetted areas of the unit and is associated with operation with a remote sump is an excellent way of reducing unit
at a pH of 8.0 or greater. capacity at low temperatures. Other methods of capacity
To prevent the formation of these porous zinc carbonate control include two-speed motors, VFDs, fan cycling and fan
cells, the interior of the unit must be passivated during start- dampers (on forced draft units only). These can be used
up and monitored periodically as part of the water treatment individually or in combination with dry / remote sump
program. A qualified water treatment company can provide a operation.
treatment program which is designed to inhibit zinc corrosion
while maintaining chemical concentrations within
recommended levels. Since re-passivation may be
necessary during normal operation, the water treatment Unit Number Minimum
program should be continually monitored. Flow (l/s)
Should any white cells begin to form, the system should be ATW / UBW 22 through 45 4.4
passivated with inorganic phosphate to prevent further cell ATW / UBW 68 through 135 8.8
formation. These deposits should not be removed with ATW / UBW 138 through 207 12.5
pressure washing, wire brushing or by any other mechanical ATW / UBW 276 through 414 25.0
ATW / UBW 432 through 864 50.0
means.

ATW 24 through 48 4.4

Stainless Steel Construction ATW 64 through 166 8.8
Units constructed of stainless steel should be inspected ATW 192 through 332 17.6
ATW 166W through 224W 17.6
annually to ensure that the surface areas remain clean and
ATW 144 through 240 25.0
free of blemishes. Stainless steel surfaces may sometimes ATW 286 through 478 50.0
become tarnished due to iron contamination such as field ATW 290 through 482 50.0
weld spatter or due to severe atmospheric conditions such as ATW 576 through 960 100.0
acidity or salty air.
LSWA 20 through 41 3.8
Any areas found with surface contamination on stainless steel LSWA 58 through 87 4.7
components should be cleaned thoroughly to restore their LSWA 116 through 174 9.5
appearance and to prevent further corrosion. All weld spatter LSWA 232 through 348 19.0
should be scubbed using an abrasive pad or stainless steel LSWA 91 through 135 8.8
bristle brush. Surface tarnish can be removed with a LSWA 182 through 270 17.6
commercial grade stainless steel cleaner.
LRW 18 3.3
LRW 30 through 60 4.7
Maintenance of Painted Surfaces LRW 72 through 96 8.8
Once a year, the protective paint of the outside the unit PMWA 116 through 174 9.5
should be inspected and cleaned. PMWA 232 through 348 19.0
If there are any signs of corrosion, clean thoroughly with a
wire brush and touch up with cold zinc.
Clean the casings of the fan motor, pump and inlet air grill.
Table 4 - Recommended minimum flow rates

© 2000 EVAPCO Inc Bulletin 112R-E Metric- 07/01 - V000 - Q1K