EVAPCO AT Series Troubleshooting guide

Operation and
Maintenance Instructions
FOR EVAPCO INDUCED DRAFT AND FORCED
DRAFT COOLING TOWERS
Bulletin 113B
For EVAPCO Authorized Parts and Service, Contact Your Local EVAPCO
Representative or the Local Mr. GoodTower®Service Provider
AT USS UT LSTB LPT
Visit EVAPCOʼs Website at:
http://www.evapco.com
EVAPCO... SPECIALISTS IN HEAT TRANSFER PRODUCTS AND SERVICES .
EVAPCO, Inc. — World Headquarters & Research/Development Center
EVAPCO, Inc.
World Headquarters
P.O. Box 1300
Westminster, MD 21158 USA
Phone: [phone]
Fax: [phone]
E-mail: [email protected]
EVAPCO Asia/Pacific
EVAPCO Asia/Pacific Headquarters
1159 Luoning Rd. Baoshan Industrial Zone
Shanghai, P. R. China, Postal Code: 200949
Phone: [phone]
Fax: [phone]
E-mail:
[email protected]
EVAPCO Europe
EVAPCO Europe, N.V.
European Headquarters
Industrieterrein Oost 4010
3700 Tongeren, Belgium
Phone: [phone]
Fax: [phone]
E-mail:
[email protected]
EVAPCO East
5151 Allendale Lane
Taneytown, MD 21787 USA
Phone: [phone]
Fax: [phone]
E-mail: [email protected]
EVAPCO Midwest
1723 York Road
Greenup, IL 62428 USA
Phone: [phone]
Fax: [phone]
E-mail: [e-mail]
EVAPCO West
1900 West Almond Avenue
Madera, CA 93637 USA
Phone: [phone]
Fax: [phone]
E-mail: [email protected]
EVAPCO Iowa
925 Quality Drive
Lake View, IA 51450 USA
Phone: [phone]
Fax: [phone]
EVAPCO Iowa
Sales & Engineering
1234 Brady Boulevard
Owatonna, MN 55060 USA
Phone: [phone]
Fax: [phone]
E-mail: [email protected]
Refrigeration Valves &
Systems Corporation
A wholly owned subsidiary of EVAPCO, Inc.
1520 Crosswind Dr.
Bryan, TX 77808 USA
Phone: [phone]
Fax: [phone]
E-mail: [email protected]
McCormack Coil Company, Inc.
A wholly owned subsidiary of EVAPCO, Inc.
P.O. Box 1727
6333 S.W. Lakeview Boulevard
Lake Oswego, OR 97035 USA
Phone: [phone]
Fax: [phone]
E-mail: [email protected]
EvapTech, Inc.
A wholly owned subsidiary of EVAPCO, Inc.
8331 Nieman Road
Lenexa, KS 66214 USA
Phone: [phone]
Fax: [phone]
E-mail: [email protected]
Tower Components, Inc.
A wholly owned subsidiary of EVAPCO, Inc.
5960 US HWY 64E
Ramseur, NC 27316
Phone: [phone]
Fax: [phone]
E-mail:
[email protected]
EVAPCO Newton
701 East Jourdan Street
Newton, IL 62448 USA
Phone: [phone]
Fax: [phone]
E-mail: [e-mail]
EVAPCO Europe, S.r.l.
Via Ciro Menotti 10
I-20017 Passirana di Rho
Milan, Italy
Phone: [phone]
Fax: [phone]
E-mail: [email protected]
EVAPCO Europe, S.r.l.
Via Dosso 2
23020 Piateda Sondrio, Italy
EVAPCO Europe, GmbH
Bovert 22
D-40670 Meerbusch, Germany
Phone: [phone]
Fax: [phone]
E-mail: [email protected]
Flex coil a/s
A subsidiary of EVAPCO ,Inc.
Knøsgårdvej 115
DK-9440 Aabybro Denmark
Phone: [phone]
Fax: [phone]
E-mail: [email protected]
EVAPCO S.A. (Pty.) Ltd.
A licensed manufacturer of EVAPCO ,Inc.
18 Quality Road
Isando 1600
Republic of South Africa
Phone: [phone]
Fax: [phone]
E-mail: [email protected]
Tiba Engineering Industries Co.
A licensed manufacturer of EVAPCO ,Inc.
5 Al Nasr Road St.
Nasr City, Cairo, Egypt
Phone: ( 20) 2-290-7483/(20) 2-291-3610
Fax: ( 20) 2-404-4667/ (20) 2-290-0892
E-mail: [email protected]
Evapco (Shanghai) Refrigeration
Equipment Co., Ltd.
1159 Louning Rd., Baoshan Industrial Zone
Shanghai, P.R. China, Postal Code: 200949
Phone: [phone]
Fax: [phone]
E-mail:
marketing @evapcochina.com
Beijing EVAPCO Refrigeration
Equipment Co., Ltd.
Yan Qi Industrial Development District
Huai Rou County
Beijing, P.R. China, Postal Code: 101407
Phone: [phone]
Fax: [phone]
E-mail: [email protected]
Evapco Australia (Pty.) Ltd.
A licensed manufacturer of EVAPCO ,Inc.
34-42 Melbourne St.
P.O. Box 436
Riverstone, N.S.W. Australia 2765
Phone: [phone]
Fax: [phone]
E-mail: [email protected]
EvapTech Asia Pacific Sdn. Bhd
A wholly owned subsidiary of EvapTech, Inc.
IOI Business Park, 2/F Unit 21
Persiaran Puchong Jaya Selatan
Bandar Puchong Jaya,
47170 Puchong, Selangor, Malaysia
Phone: [phone]
Fax: [phone]
E-mail: [email protected]
EVAPCO North America
EVAPCO, Inc. • P.O. Box 1300 • Westminster, MD 21158 USA
PHONE:[phone]•FAX: [phone] • E-MAIL: [email protected]
Cert no. BV-COC-080211

2
Operation and Maintenance Instructions
Table of Contents
Introduction . . ...............................................................................3
Safety Precautions ...........................................................................3
Initial Storage and/or Idle Period Recommendations ...............................................3
InternationalBuildingCodeProvision ...........................................................3
Initial and Seasonal Start-Up Checklist ...........................................................4
General ................................................................................4
InitialandSeasonalStart-Up ...............................................................4
Maintenance Checklist ....................................................................5
Seasonal Shut-Down Checklist .............................................................7
FanSystem .................................................................................7
FanMotorBearings ......................................................................7
FanShaftBearings .......................................................................7
Recommended Bearing Lubricants ..........................................................7
Fan Belt Adjustment ......................................................................8
Fan and Motor Sheave Alignment ...........................................................8
Fan System Capacity Control ..............................................................10
Fan Motor Cycling .................................................................10
TwoSpeedMotors .................................................................10
VariableFrequencyDrives ...........................................................11
RecirculatedWaterSystemRoutineMaintenance .................................................12
ColdWaterBasin .......................................................................12
Suction Strainer Assembly ................................................................12
OperatingWaterLevels ..................................................................12
Water Make Up Valve . . . .................................................................13
Pressurized Water Distribution System ......................................................13
Drift Eliminator Orientation ...........................................................15
WaterTreatmentandWaterChemistryoftheRecirculatedWaterSystem .............................16
BleedOff ..............................................................................16
Biological Contamination .................................................................16
Air Contamination .......................................................................16
WaterChemistryParameters ..............................................................17
PassivationofGalvanizedSteel ............................................................18
WhiteRust .......................................................................18
UseofSoftWater .......................................................................19
UseofGrayWater .................................................................19
StainlessSteel ..............................................................................19
Maintaining the Appearance of Stainless Steel ................................................19
Cleaning Procedures for Stainless Steel .....................................................20
Cold Weather Operation ......................................................................20
ReplacementParts ..........................................................................23
Part Identification Drawings ...............................................................24
ICT 4ʼ Wide Towers ................................................................24
AT/USS 6ʼ, 8ʼ & 8.5ʼ Wide Towers . . . . . . ...............................................25
AT/USS 10ʼ, 12ʼ, & 14ʼ Wide Towers . . . . . . . . . . . . .......................................26
AT/USS 12ʼ, 15ʼ & 17ʼ Wide End Connection Towers . . ....................................27
AT/USS20ʼ&24ʼWideTowers .......................................................28
AT/USS 28ʼ Wide Towers . . . . . . . . . . . . ................................................29
UT 6ʼ, 7.5ʼ, 8ʼ & 8.5ʼ Wide Towers . . . . . . . ..............................................30
UT 10ʼ, 12ʼ, & 14ʼ Wide Towers . . . . . . . . . . . ............................................31
UT 12ʼ, 15ʼ & 17ʼ Wide End Connection Towers . . . . . . . . . . . ...............................32
UT20ʼ&24ʼWideTowers ...........................................................33
UT 28ʼ Wide Towers . . . . . . ..........................................................34
LPTUnits ........................................................................35
LSTA 4ʼ Wide Units . . ..............................................................36
LSTBUnits.......................................................................37
Notes............................................................................38

3
Operation and Maintenance Instructions
Introduction
Congratulations on the purchase of your EVAPCO evaporative cooling unit. EVAPCO equipment is constructed of the highest
quality materials and designed to provide years of reliable service when properly maintained.
Evaporative cooling equipment is often remotely located and periodic maintenance checks are often overlooked. It is important to
establish a regular maintenance program and be sure that the program is followed. This bulletin should be used as a guide to
establish a program. A clean and properly serviced unit will provide a long service life and operate at peak efficiency.
This bulletin includes recommended maintenance services for unit start up, unit operation and unit shutdown and the frequency of
each. Please note: the recommendations of frequency of service are minimums. Services should be performed more often when
operating conditions necessitate.
Become familiar with your evaporative cooling equipment. Refer to the isometric drawings located on pages 25-35 for information
on the arrangement of components in your equipment.
If you should require any additional information about the operation or maintenance of this equipment, contact your local EVAPCO
representative. You may also visit www.evapco.com or www.mrgoodtower.com for more information.
Safety Precautions
Qualified personnel should use proper care, procedures and tools when operating, maintaining or repairing this equipment in order
to prevent personal injury and/or property damage. The warnings listed below are to be used as guidelines only.
WARNING: This equipment should never be operated without fan screens and access doors properly secured and in place.
WARNING: A lockable disconnect switch should be located within sight of the unit for each fan motor associated with
this equipment. Before performing any type of service or inspection of the unit make certain that all power
has been disconnected and locked in the “OFF” position.
WARNING: The top horizontal surface of any unit is not intended to be used as a working platform. No routine service
work is required from this area.
WARNING: The recirculating water system may contain chemicals or biological contaminants including Legionella
Pneumophila, which could be harmful if inhaled or ingested. Direct exposure to the discharge airstream and
the associated drift generated during operation of the water distribution system and/or fans, or mists
generated while cleaning components of the water system require respiratory protection equipment
approved for such use by governmental occupational safety and health authorities.
Initial Storage and/or Idle Period Recommendations
If the unit will sit idle for long periods of time it is recommended that the following be performed in addition to all component
manufacturers recommended maintenance instructions.
•The fan bearings and motor bearings need to be turned by hand at least once a month. This can be accomplished by
tagging and locking out the unitʼs disconnect, grasping the fan assembly, and rotating it several turns.
•If unit sits longer than a few weeks, run gear reducer for 5 minutes weekly.
•If unit sits longer than 3 weeks, completely fill gear reducer with oil. Drain to normal level prior to running.
•If unit sits longer than one month, insulation test motor windings semi-annually.
•If fan motor sits idle for at least 24 hours while the spray pumps are energized distributing water over the heat transfer media,
motor space heaters (if equipped) should be energized. Alternatively, fan motors may be energized for 10 minutes, twice
daily, to drive any moisture condensation out of the motor windings.
International Building Code Provisions
The International Building Code (IBC) is a comprehensive set of regulations addressing the structural design and installation
requirements for building systems – including HVAC and industrial refrigeration equipment. The code provisions require that
evaporative cooling equipment and all other components permanently installed on a structure must meet the same seismic design
criteria as the building.
All items attached to Evapco Cooling Towers must be independently reviewed and isolated to meet applicable wind and seismic
loads. This includes piping, ductwork, conduit, and electrical connections. These items must be flexibly attached to the Evapco

4
Operation and Maintenance Instructions
unit so as not to transmit additional loads to the equipment as a result of seismic or wind forces.
Initial and Seasonal Start-Up Checklist
General
1. Verify that the overall installation reflects the requirements of the installation guidelines found in EVAPCO Bulletin 311 –
Equipment Layout Manual.
2. For multi-speed fan motors, verify that 30 second or greater time delays are provided for speed changes when switching from
high to low speed. Also check to see if interlocks are provided to prevent simultaneously energizing high and low speed and
confirm both speeds operate in the same direction.
3. Verify all safety interlocks work properly.
4. For units operating with a variable frequency drive, make certain that minimum speed requirements have been set. Check with
VFD manufacturer for recommended minimum speeds and recommendations on locking out resonance frequencies. See “Fan
System Capacity Control” section for more information.
5. Verify that the sensor used for fan sequencing and by-pass valve control is located downstream of the point where the by-pass
water mixes with the condenser supply water, if applicable.
6. Verify that a water treatment plan has been implemented including passivation of galvanized steel units. See “Water
Treatment” section for more details.
7. For units subject to freezing climates, high humidity climates, or idle periods lasting 24 hours or more, motor space heaters (if
equipped) should be energized. Alternatively, fan motors may be energized for 10 minutes, twice daily, to drive any moisture
condensation out of the motor windings.
8. If the unit is going to sit idle for an extended period of time, follow all manufacturersʼ fan motor and pump instructions for long
term storage. Plastic sheets or tarps should never be used to protect a unit during storage. This practice can trap heat inside
the unit, and could potentially cause damage to plastic components. See your local EVAPCO representative for additional
information on unit storage.
BEFORE BEGINNING ANY MAINTENANCE, BE CERTAIN THAT THE POWER IS TURNED OFF
AND THE UNIT IS PROPERLY LOCKED AND TAGGED OUT!
Initial and Seasonal Start-Up
1. Clean and remove any debris, such as leaves and dirt from the air inlets.
2. Flush the cold water basin (with the strainer screens in place) to remove any sediment or dirt.
3. Remove the strainer screen, clean and reinstall.
4. Check mechanical float valve to verify it operates freely.
5. Inspect water distribution system nozzles and clean as required. Check for proper orientation. (This is not required at initial
start-up. The nozzles are clean and set at the factory).
6. Check to ensure drift eliminators are securely in place.
7. Adjust fan belt tension as required.
8. Lubricate fan shaft bearings prior to seasonal start-up.
9. Turn the fan(s) by hand to insure it turns freely without obstructions.
10. Visually inspect the fan blades. Blade clearance should be approximately 3/8” (1/4” minimum) from tip of blade to the fan cowl.
The fan blades should be securely tightened to the fan hub.
11. If any stagnant water remains in the system including “dead legs” in the piping, the unit must be disinfected prior to the fans
being energized. Please refer to Ashrae Guideline 12-2000 and CTI Guideline WTP-148 for more information.
12. Fill the cold water basin manually up to the overflow connection.
After the unit has been energized, check the following:
1. Adjust mechanical float valve as required to the proper water level.
2. Unit basin should be filled to the proper operating level. See “Recirculating Water System – Operating Levels” section for more
details.
3. Verify fan is rotating in proper direction.
4. Measure voltage and current on all three power leads. The current should not exceed the motor nameplate full load amp rating
taking the service factor into account.
5. Adjust bleed valve to proper flow rate. Maximum bleed off is 3 US GPM per 100 tons. Consult your qualified water treatment
person to fine tune the minimum bleed necessary.
6. Refer to the fan motor manufacturerʼs maintenance and long term storage instructions for more detailed information. Motors
should be serviced in accordance with manufacturerʼs instructions.

5
Operation and Maintenance Instructions
PROCEDURE
1. Clean pan strainer – monthly or as needed
2. Clean and flush pan** – quarterly or as needed
3. Check bleed-off valve to make sure it is
operative – monthly
4. Check operating level in pan and adjust float
valve if necessary – monthly
5. Check water distribution system and spray
pattern – monthly
6. Check drift eliminators – quarterly
7. Check the fan blades for cracks, missing
balancing weights, and vibrations – quarterly
8. Lubricate fan shaft bearings* – every 1000
hours of operation or every three months
9. Check belt tension and adjust – monthly
10. Sliding motor base – Inspect and grease –
annually or as needed
11. Check fan screens, inlet louvers and fans.
Remove any dirt or debris – monthly
12. Inspect and clean protective finish – annually
- Galvanized: scrape and coat with ZRC
- Stainless: clean and polish with a
stainless steel cleaner.
13. Check water quality for biological contamination.
Clean unit as needed and contact a water
treatment company for recommended water
treatment program** – regularly
1. Gear Reducer – Check oil level with unit
stopped – 24 hours after start-up & monthly
2. Gear Reducer/Piping – Do visual inspection
for oil leaks, auditory inspection for unusual
noises and vibrations – monthly
3. Gear Reducer - Replace oil – semi-annually
4. Oil Pump – Do visual inspection for leaks and
proper wiring – monthly
5. Gear Reducer/Coupling – Check alignment of
the system – 24 hours after start-up & monthly
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
OPTIONAL ACCESSORIES:
MAINTENANCE
CHECKLIST
* See maintenance manual for start-up instructions and lubrication recommendations.
** Cooling Towers must be cleaned on a regular basis to prevent the growth of bacteria including Legionella Pneumophila.

6
Operation and Maintenance Instructions
OPTIONAL ACCESSORIES:
6. Coupling/Shaft – Inspect flex elements and
hardware for tightness, proper torque &
crack/deterioration – monthly
7. Heater Controller – Inspect controller and
clean probe ends – quarterly
8. Heater – Inspect junction box for loose wiring
and moisture – one month after start-up and
semi-annually
9. Heater – Inspect elements for scale
build-up – quarterly
10. Electronic Water Level Controller – Inspect
junction box for loose wiring and moisture –
semi-annually
11. Electronic Water Level Controller – Clean
probe ends of scale build-up – quarterly
12. Electronic Water Level Controller –Clean
inside the standpipe – annually
13. Solenoid Make-up Valve – Inspect and clean
valve of debris – as needed
14. Vibration Switch (mechanical) – Inspect
enclosure for loose wiring and moisture –
one month after start-up and monthly
15. Vibration Switch – Adjust the sensitivity –
during start-up and annually
16. Sump Sweeper Piping – Inspect and clean
piping of debris – semi-annually
17. Water Level Indicator – Inspect and clean –
annually
1. Few Days: Energize motor space heaters
–when motor is idle
2. Few Weeks: Run gear reducer for 5 minutes
–weekly
3. Several Weeks: Completely fill gear reducer
with oil. Drain to normal level prior to running.
4. One Month or longer: Rotate motor shaft/fan
10 turns – bi-weekly
5. One Month or longer: Megger test motor
windings – semi-annually
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
DURING IDLE PERIODS:
MAINTENANCE
CHECKLIST

7
Operation and Maintenance Instructions
Seasonal Shut-Down Checklist
When the system is to be shut down for an extended period of time, the following services should be performed.
1. The evaporative cooling unit should be drained.
2. The cold water basin should be flushed and cleaned with the suction strainer screens in place.
3. The suction strainer screens should be cleaned and re-installed.
4. The cold water basin drain should be left open.
5. The fan shaft bearings and motor base adjusting screws should be lubricated.
6. The water make up valve needs to be closed. All water make-up piping needs to be drained, if not heat traced and
insulated.
7. The finish of the unit should be inspected. Clean and refinish as required.
8. The fan bearings and motor bearings need to be turned at least once a month by hand. This can be accomplished by
making sure the unitʼs disconnect is locked and tagged out, and grasping the fan assembly, rotating it several turns.
9. Energize motor space heaters.
Fan System
The fan systems of both centrifugal and axial driven units are rugged, however, the fan system must be checked regularly and
lubricated at the proper intervals. The following maintenance schedule is recommended.
Fan Motor Bearings
EVAPCO evaporative cooling units use either a T.E.A.O. (Totally Enclosed Air Over) or a T.E.F.C. (Totally Enclosed Fan Cooled) fan
motor. These motors are built to “Cooling Tower Duty” specifications. They are supplied with permanently lubricated bearings and
special moisture protection on the bearings, shaft and windings. After extended shut-downs, the motor should be checked with an
insulation tester prior to restarting the motor.
Fan Shaft Ball Bearings
Lubricate the fan shaft bearings every 1,000 hours of operation or every three months for induced draft units. Lubricate the fan
shaft bearings every 2,000 hours of operation or every six months for forced draft units. Use any of the following synthetic
waterproof, polyurea inhibited greases which are suitable for operation between -20°F and 350°F. (For colder operating
temperatures, contact the factory).
Mobil – Polyrex EM Chevron - SRI
Feed grease slowly into the bearings or the seals may be damaged. A hand grease gun is recommended for this process.
When introducing a new grease, all grease should be purged from the bearings.
All EVAPCO units are supplied with extended grease lines to allow easy lubrication of the fan shaft bearings.

8
Operation and Maintenance Instructions
Fan Shaft Sleeve Bearings – (4ʼ wide LSTA units only)
Lubricate the intermediate sleeve bearing(s) before unit start up. The reservoir should be checked several times during the first
week to ensure that the oil reserve is brought to full capacity. After the first week of operation, lubricate the bearing(s) every 1,000
hours of operation or every three months (whichever occurs first). High temperatures or poor environmental conditions may
necessitate more frequent lubrication. The oil reservoir consists of a large felt packed cavity within the bearing housing. It is not
necessary to maintain the oil level within the filler cup.
Use one of the following industrial grade, non-detergent mineral oils. Do not use a detergent based oil or those designated
heavy duty or compounded. Different oils may be required when operating at temperatures below 30°F continuously. Table 2
provides a short list of approved lubricants for each temperature range. Most automotive oils are detergent based and may not be
used. Detergent oils will remove the graphite in the bearing sleeve and cause bearing failure.
All bearings used on EVAPCO equipment are factory adjusted and self aligning. Do not disturb bearing alignment by tightening the
sleeve bearing caps.
Fan Belt Adjustment
The fan belt tension should be checked at start up and again after the first 24 hours of operation to correct for any initial stretch. To
properly adjust the belt tension, position the fan motor so that the fan belt will deflect approximately 1/2” when moderate pressure
is applied midway between the sheaves. Figure 1 and Figure 2 show two ways to measure this deflection. Belt tension should be
checked on a monthly basin. A properly tensioned belt will not “chirp” or “squeal” when the fan motor is started.
Table 1 - Location of Grease Lube Line Fittings for Belt Driven Units.
Please note, the removal of the fan screens is not necessary on forced draft units to access the extended lube line fittings.
Unit Description Location of Lube Line Fittings
Induced Draft Units: Located just beside the fan casing
6', 8', 8.5', 12', 15' and 17' wide access door
Induced Draft Units: Located inside the fan casing
All Others access door
LSTB Forced Draft Units Located on the front of the unit
LPT Forced Draft Units Located on the front of the unit
LSTA 4' Wide Forced Draft Units See Below
Ambient Temp Texaco Drydene Exxon
30°F to 100°F Regal R&O 220 Paradene 220 Terrestic 220
-25°F to 30°F Capella WF 32 Refrig. Oil 3G ------------------
Table 2 - Sleeve Bearing Lubricants
Figure 1 – Method 1 Figure 2 – Method 2

9
Operation and Maintenance Instructions
On induced draft belt driven units provided with externally mounted motors (6, 8, 8.5, 12, 15 and 17 foot wide units), Figure 3, and
LSTB forced draft units, Figure 4, both J-type adjustment bolts on the adjustable motor base should have an equal amount of
exposed thread for proper sheave and belt alignment.
Figure 3 – Externally Mounted Motors Figure 4 – LSTB Externally Mounted Motor
Figure 5 – Internally Mounted Motors
On induced draft belt driven units with internally mounted motors (10, 12, 14, 20, 24 and 28 foot wide units), Figure 5, and LPT units,
Figure 6, a motor adjustment tool is provided. The tool will be found on the adjustment nut. To use, place the hex end over the
adjustment nut. Tension the belt by turning the nut counterclockwise. When the belts are properly tensioned, tighten the lock nut.

10
Operation and Maintenance Instructions
Direct drive fan units do not require any adjustment (4' Wide Induced Draft ICT Models Only).
Fan System — Capacity Control
There are several methods for capacity control of the evaporative cooling unit. Methods include: Fan motor cycling, the use of two
speed motors and the use of variable frequency drives (VFDʼs). In all cases, if motors are idle for extended periods of time with
water still being directed over heat transfer media, motor space heaters are suggested.
Fan Motor Cycling
Fan Motor Cycling requires the use of a single stage thermostat which senses the water temperature. The contacts of the
thermostat are wired in series with the fan motorʼs starter holding coil.
Fan Motor Cycling is often found to be inadequate where the load has a wide fluctuation. In this method, there are only two stable
levels of performance: 100% of capacity when the fan is on and approximately 10% of capacity when the fan is off. Please note,
rapid cycling of the fan motors can cause the fan motor to overheat. Controls should be set to only allow a maximum of six (6)
start/stop cycles per hour.
Two Speed Motors
The use of a two speed motor provides an additional step of capacity control when used with the fan cycling method. The low
speed of the motor will provide 60% of full speed capacity.
Two speed capacity control systems require not only a two speed motor, but a two stage thermostat and the proper two speed
motor starter. The most common two speed motor is a single winding type. This is also known as a consequent pole design. Two
speed two winding motors are also available. All multi-speed motors used in evaporative cooling units should be variable torque
design.
It is important to note that when two speed motors are to be used, the motor starter controls must be equipped with a decelerating
time delay relay. The time delay should be a minimum of a 30 second delay when switching from high speed to low speed.
Figure 6 – LPT Motor Adjustment

11
Operation and Maintenance Instructions
Sequence of Operation for Two Fan Units with Two Speed Motors During Peak Load
1. Both fan motors on full speed – full water flow over both cells
2. One fan motor on high speed, one fan motor on low speed – full water flow over both cells
3. Both fan motors on low speed – full flow over both cells
4. One fan motor on low speed, one fan motor off – full water flow over both cells
5. Both fan motors off – full water flow over both cells
6. Both fan motors off – full single cell flow through one cell
Variable Frequency Drives
The use of a variable frequency drive (VFD) provides the most precise method of capacity control. A VFD is a device that converts
a fixed AC voltage and frequency and changes it into an AC adjustable voltage and frequency used to control the speed of an AC
motor. By adjusting the voltage and frequency, the AC induction motor can operate at many different speeds.
The use of VFD technology can also benefit the life of the mechanical components with fewer and smoother motor starts and built
in motor diagnostics. VFD technology has particular benefit on evaporative cooling units operating in cold climates where airflow
can be modulated to minimize icing and reversed at low speed for de-icing cycles. Applications using a VFD for capacity control
must also use an inverter duty motor built in compliance with NEMA standard MG-1. This is an available option from EVAPCO. The
standard fan motors supplied by EVAPCO are not intended for use with VFDʼs.
The type of motor, manufacturer of the VFD, motor lead lengths (between the motor and the VFD), conduit runs and grounding can
dramatically affect the response and life of the motor. The motor lead length restrictions vary with the motor vendor. Regardless of
motor supplier, minimizing motor lead length between the motor and the drive is good practice.
Sequence of Operation for Multi-fan Units with a VFD During Peak Load
1. The VFDs should all be synchronized to speed up and slow down uniformly.
2. The VFDs need to have a pre-set shutoff to prevent water temperatures from becoming too cold and to prevent the drive
from trying to turn the fan at near zero speed.
3. Operating below 25% of motor speed achieves very little return in fan energy savings and capacity control. Check with
your VFD supplier if operating below 25% is possible.
For more details on the use of variable frequency drives, please request copies of EVAPCOʼs Engineering Bulletins 39 and 43.

12
Operation and Maintenance Instructions
Recirculated Water System – Routine Maintenance
Suction Strainer in Cold Water Basin
The pan strainer should be removed and cleaned monthly or as often as necessary. The suction strainer is the first line of defense
in keeping debris out of the system. Make certain that the strainer is properly located over the pump suction, alongside the anti-
vortexing hood.
Cold Water Basin
The cold water basin should be flushed out quarterly, and checked monthly or more often if necessary, to remove any accumulation
of dirt or sediment which normally collects in the basin. Sediment can become corrosive and cause deterioration of basin materials.
When flushing the basin, it is important to keep the suction strainers in place to prevent any sediment from entering the system.
After the basin has been cleaned, the strainers should be removed and cleaned before refilling the basin with fresh water.
Operating Level of Water in Cold Water Basin
The operating level should be checked monthly to make sure the water level is correct. Refer to Table 3 for unit specific levels.
Figure 7 – Single Strainer Assembly Figure 8 – Dual Strainer Assembly
Model Number OperatingDepth*
ICT 3-63 through 3-93 6”
ICT 4-54 through 4-912 7”
UBT 8-56B through 24-918B 9”
AT/USS 14-64 through 14-912 7”
AT/USS/UT 19-56 through 224-918 9”
AT/USS/UT 424-024 through 428-948 11”
LSTA 4-61 through 4-185 9”
LSTB 5112 through 8P536 9”
LSTB 10112 through 10636 13”
LPT 316 through 8812 8”
* Measured from lowest point on basin floor.
Table 3 - Recommended Operating Water Level

13
Operation and Maintenance Instructions
At initial start up or after the unit has been drained, the unit must be filled to the overflow level. Overflow is above the normal
operating level and accommodates the volume of water normally in suspension in the water distribution system and some of the
piping external to the unit.
The water level should always be above the strainer. Check by running the pump with the fan motors off and observing the water
level through the access door or remove the air inlet louver.
Water Make Up Valve
A mechanical float valve assembly is provided as standard equipment on the evaporative cooling unit (unless the unit has been
ordered with an optional electronic water level control package or the unit is arranged for remote sump operation). The make up
valve is easily accessible from outside the unit through the louver access door or removable air inlet louver. The make up valve is a
bronze valve connected to a float arm assembly and is activated by a large foam filled plastic float. The float is mounted on an all
thread rod held in place by wing nuts. The water level in the basin is adjusted by repositioning the float and all thread using the
wing nuts. Refer to Figure 9 for details.
The make up valve assembly should be inspected monthly and adjusted as required. The valve should be inspected annually for
leakage and if necessary, the valve seat should be replaced. The make up water pressure should be maintained between 20 and
50 PSIG.
Pressurized Water Distribution Systems
All EVAPCO cooling towers are supplied with wide orifice water diffusers. The water distribution system should be checked monthly
to make sure it is operating properly. Always check the spray system with the pump on and the fans off (locked and tagged out).
On forced draft units (LSTB, LPT and LSTA models), remove one or two eliminator sections from the top of the unit and observe
the operation of the water distribution system.
On induced draft units (AT, USS, UT and ICT models), lifting handles are provided on several sections of eliminators within reach of
the access door. Eliminators can be easily removed from outside of the unit to observe the water distribution system. The diffusers
are essentially non-clogging and should seldom need cleaning or maintenance.
Figure 9 – Mechanical Water Make Up Valve

14
Operation and Maintenance Instructions
If the water diffusers are not functioning properly, it is a sign that the suction strainer has not been working properly and that foreign
matter or dirt has accumulated in the water distribution pipes. The nozzles can be cleared by taking a small pointed probe and
moving it back and forth in the diffuser opening.
If an extreme build up of dirt or foreign matter occurs, remove the end cap in each branch to flush the debris from the header pipe.
The spray branches and header can be removed for cleaning, but should only be done if absolutely necessary.
After the water distribution system has been cleaned, the suction strainer should be checked to make sure it is in good operating
condition and positioned properly so that cavitation or air entrapment does not occur.
When inspecting and cleaning the water distribution system, always check that the orientation of the water diffusers is correct as
shown below for LSTB, LPT and LSTA models in Figure 10 and as shown in Figure 11 for AT, USS and UT models. The top of the
EVAPCO logo on the nozzle is parallel with the top of the water distribution pipe.
THREADED END CAP
Figure 10 – LSTA/LSTB/LPT Water Distribution
Figure 11 – AT/USS/UT Water Distribution
UNIT
END WALL

15
Operation and Maintenance Instructions
Drift Eliminators
Induced Draft Units (AT, USS, and UT Models)
Orientation of the eliminator sections on induced draft units is not critical. Note though, that the eliminator sections must fit tightly
together within the fan section of the unit.
Forced Draft Units (LSTB, LPT and LSTA Models)
The eliminator sections are constructed of PVC and are not designed to support the weight of a person or to be used as a work
surface for any equipment or tools. Use of these eliminators as a walking surface or working platform may result in injury to
personnel or damage to the equipment.
Figure 12 – Drift Eliminators Figure 13 – Drift Eliminator Orientation on LPT units
Figure 14 – Drift Eliminator Orientation on LSTA units Figure 15 – Drift Eliminator Orientation on LSTB units

16
Operation and Maintenance Instructions
Water Treatment and Water Chemistry of the Recirculated Water System
It is recommended that a qualified water treatment company be contacted to design a water treatment protocol specifically for
equipment and location. Contact your local EVAPCO representative for assistance.
Evaporative cooling equipment rejects heat by evaporating a portion of the recirculated water and discharging it into the
atmosphere in the hot, saturated discharge air. As the water evaporates, it leaves behind all the mineral content and impurities. If
the water chemistry is not controlled properly, the residuals may become concentrated and lead to corrosion, scaling, sludge build
up and biological fouling. Corrosion would be identified as red rust on steel components or white rust on galvanized steel.
Corrosion will adversely affect the longevity of the tower. Scale reduces heat transfer efficiency and system efficiency, while scale
and sludge can both lead to under deposit corrosion. Biological fouling such as slime and algae may reduce the unitʼs heat
transfer, promote corrosion and possibly harbor pathogens such as Legionella Pneumophila.
Bleed Off
As a minimum, to avoid the build up of residuals in the water distribution system, water must be drained out of the system at a rate
large enough to the control the system water chemistry. The maximum amount of bleed is equal to the rate of evaporation based
on 2 cycles of concentration.
Open cooling towers need to have a bleed line installed on the discharge side of the system pump. A metering device and globe
valve should also be provided. The metering device is used to determine the bleed water volume. The globe valve is used to
regulate flow.
Another method to remove residuals is to use a conductivity controlled blowdown device. This method should also be considered
for water savings.
Biological Contamination
Water quality should be checked regularly for biological contamination. If biological contamination is detected, a more aggressive
water treatment and mechanical cleaning program is required. The water treatment program should be performed in conjunction
with a qualified water treatment company. It is important that all internal surfaces be kept clean of accumulated dirt or sludge. In
addition, the drift eliminators should be kept in good operating condition to minimize water from exiting the evaporative cooling unit
in the discharge air.
To minimize the risk of biological contamination, at initial start up or after an extended shut down, it is recommended that the entire
system (cooling tower, system piping, heat exchanger, etc.) be properly treated. Clean all debris such as leaves and dirt from the
unit. Completely fill the basin to the overflow level with fresh water. Initiate a biocide water treatment or shock treatment program
prior to operating the unit. It is preferable that all such procedures be conducted or supervised by a water treatment specialist.
Air Contamination
If the unit is located in an area where there are contaminents such as: chemical fumes, industrial smoke, salt or heavy dust, the
impurities in the air will be washed out in the recirculated water and may cause scaling, corrosion or accelerated biological growth.
It is important not to locate the unit next to smokestacks, discharge ducts, vents, flue gas exhausts, etc. because the unit will draw
in these fumes which may lead to extremely corrosive conditions. It is also important to locate the unit away from the buildingʼs
fresh air intakes to prevent any drift or other unit discharge from entering the buildingʼs air system. The quantity of impurities in the
air will determine the frequency of the maintenance program. Bleeding off the impurities will help, but if there are any signs of
corrosion, scaling or biological growth, the qualified water treatment specialist should be contacted.

17
Operation and Maintenance Instructions
Water Chemistry Parameters
A proper water treatment program is an essential part of routine maintenance to ensure the safe operation and longevity of this
unit. A water treatment company familiar with local water conditions should be consulted.
Any water treatment system used in the unit must be compatible with the unitʼs materials of construction. Although high quality
galvanized steel is used in most units, alternate materials of construction such as stainless steel (Type 304 or Type 316) are
increasingly being used.
To control corrosion and scale, the recirculating water chemistry must be within certain ranges as shown in Table 4, or within the
limits provided by your local water treatment specialist.
Property G-235 Type 304 Type 316
Galvanized Steel Stainless Steel Stainless Steel
pH** 6.5 to 8.3 6.5 to 9.0 6.5 to 9.0
Hardness as CaCO3 (ppm) 50 to 300 < 300 < 300
Alkalinity as CaCO3 (ppm) 50 to 300 < 500 < 500
Total Suspended Solids (ppm)* < 25 < 25 < 25
Bacteria Count (cfu/ml) < 10,000 < 10,000 < 10,000
Conductivity (Micro-mhos/cm) < 2,400 < 3,500 < 5,000
Chlorides as Cl (ppm) < 250 < 400 < 4,000
Chlorides as NaCl (ppm) < 410 < 660 < 6,600
Sulfates (ppm) < 250 < 500 < 1,000
Silica as SiO2(ppm) < 150 < 150 < 150
* Based on standard EVAPAK®fill
** Galvanized steel units require routine passivation when the operating pH is 8.3 or higher to prevent “White Rust”.
See “Passivation” and “White Rust” sections for more details.
TABLE 4 – Guidelines for Recommended Water Chemistry*

18
Operation and Maintenance Instructions
If a chemical water treatment program is used, the chemicals selected must be compatible with the unit materials of construction as
well as other materials used in the system. The chemicals must be accurately metered and concentrations properly controlled.
Chemicals should be introduced through automatic feeders at a point in the system where total mixing can occur before reaching
the evaporative cooling equipment. Chemicals should never be batch fed directly into the unitʼs basin or water distribution system.
The use of acid should be avoided. If acid cleaning is required, only inhibited acids recommended for use with the unitʼs materials
of construction should be used.
Passivation of Galvanized Steel
Passivation is the formation of a protective zinc carbonate layer on galvanized steel. The zinc carbonate layer protects the
galvanized surface by sacrificing itself slowly over time. This layer can be diminished by walking on the surface or by pressure
washing.
Heavy mill galvanizing provides an excellent corrosion resistant barrier for the substrate steel on an evaporative cooling unit. The
zinc finish is a reactive metal which acts as a sacrificial anode to protect the steel substrate. Units that are operated within the
recommended pH levels of 6.5 to 8.3 and are passivated allow a surface barrier of non-porous zinc carbonate and zinc hydroxide
to form which prevents rapid galvanic corrosion. This basic zinc carbonate barrier must be allowed to form in order to provide
maximum protection for the mill galvanized steel.
Steel mills producing galvanized steel perform a passivation wash after processing the steel. This mill applied passivation is
only a temporary passivation program. The unit must be passivated during the unit start up phase and must be part of the
water treatment program. Passivation of the galvanized steel surface is critical to prevent the formation of “white rust”
and to extend the life of evaporative cooling equipment.
To prevent the formation of “white rust” (porous zinc carbonate cells), the interior of the unit must be passivated during start up and
monitored periodically as part of the water treatment program. A qualified water treatment program should be designed to inhibit
zinc corrosion while maintaining chemical concentrations within recommended levels. Since re-passivation may be necessary
during normal operation, the water treatment program should be continually monitored.
The passivation program should operate for a period of 45 to 60 days. The pH of the circulating water must be between 7.0 and
8.0; hardness measured as CaCO3 should be between 100-300 ppm; and alkalinity measured as CaCO3 should be between 100-
300 ppm.
If white zinc deposits form on the galvanized steel surfaces after the pH is returned to normal operating levels, it may be necessary
to repeat the passivation process. These deposits should not be removed with pressure washing, wire brushing or by any other
mechanical means. See Section titled “White Rust” for more information.
White Rust
White rust is defined as “the rapid formation of non-protective zinc carbonate cells on the surface of galvanized steel”. These
deposits appear as white powdery cells and are considered to be a zinc corrosion by-product. These cells are porous and allow
continued corrosion of any non-passivated galvanized steel surface. This type of corrosion is most prevalent in the wetted areas
of evaporative cooling products. Water chemistry that promotes the formation of “white rust” includes:
1. pH levels greater than 8.3
2. Calcium hardness as CaCO3 less than 50 ppm
3. Anions of sulfates, chlorides and nitrates greater than 250 ppm
4. Soft water with calcium hardness (CaCO3) less than 50 ppm combined with a high alkalinity greater than 300 ppm
(CaCO3) and a pH greater than 8.3
It should be noted that not all white deposits found on galvanized steel surfaces are due to white rust. As a result, it is imperative to
determine the inorganic content of the deposit. The deposits may be calcium based and not zinc based.
For more information, please request a copy of EVAPCOʼs Engineering Bulletin 36 on White Rust.

19
Operation and Maintenance Instructions
Soft Water
The use of soft water with a galvanized steel unit is not recommended. Soft water is corrosive to galvanized steel.
In general, both Type 304 and Type 316 stainless steel exhibit good corrosion resistance to soft water. However, soft water is
usually generated from water softeners which typically use a brine solution (concentrated salt water) to regenerate. After
regeneration, this brine is flushed. If the softener is out of adjustment, not all the brine will flush out and this salt (NaCl) will be
carried out with the finished water. This poses the risk of high chlorides in the unitʼs recirculated water. Type 304 stainless steel is
susceptible to corrosion at high chloride levels. Type 316 stainless steel is more resistant to this corrosion.
Gray Water
Gray water is broadly defined as any water that has been used in a home or commercial environment, except water from toilets.
The use of gray water can be considered as long as the water chemistry conforms to the parameters found in the Water Treatment
section of this bulletin and understanding the risks of fouling or biological contamination when gray water is used. Gray water
should be avoided unless all of the risks are understood and taken into account.
Stainless Steel
Stainless steel is the most cost effective material of construction available to extend the life of an evaporative cooling unit.
The stainless steel sheet material utilized by EVAPCO is Type 304 and Type 316 with a No. 2B unpolished finish. Type 304
stainless steel is a basic chromium-nickel austenitic stainless steel and is suitable for a wide range of applications. It is readily
available throughout the world and is easy to form during the fabrication process. Type 316 stainless steel offers more corrosion
resistance than Type 304 due to the addition of molybdenum and a higher nickel content, which provides greater resistance to
pitting and crevice corrosion in the presence of chlorides. As a result, Type 316 stainless steel is desirable in heavy industrial,
marine environments and where make up water quality requires it.
Stainless steel provides its superior corrosion resistance by developing a surface film of chromium oxide during the manufacturing
process. In order to ensure maximum corrosion protection, stainless steel must be kept clean and have an adequate supply of
oxygen to combine with the chromium in the stainless steel to form “chromium-oxide”, a protective passivation layer. The protective
layer of chromium-oxide develops during routine exposure to the oxygen content in the atmosphere. This occurs during the milling
process and continuously as the stainless is formed and shaped for its final use.
Maintaining the Appearance of Stainless Steel
It is a common misconception that stainless steel is stain and rust proof, making surface maintenance not required at all. This is
simply not true. Like mill galvanized steel, stainless steel is most effective when kept clean. This is especially true when located in
atmospheres with chloride salts, sulfides or other rusting metals. In these environments, stainless steel can discolor, rust or
corrode.
Once the unit arrives at the job site, the most effective way of maintaining the stainless steel finish is to keep it clean! At a
minimum, the unit should be washed down annually to reduce residual dirt or surface deposits on the stainless steel. In addition,
this wash down will keep the stainless steel components free from the corrosive elements in the atmosphere including chlorides
and sulfides which are damaging to stainless steel.
Protect stainless steel during unit installation, especially welding of nearby carbon steel pipes as weld stag or other corroding
materials may cause staining in stainless shell if not protected or cleaned.

20
Operation and Maintenance Instructions
Cleaning of Stainless Steel
Routine Maintenance – Mild Cleaning
Simple pressure washing (of sheet metal components only), using household cleaners, detergents or ammonia annually
(more frequently in marine or industrial environments) will help maintain the finish and keep it free of atmospheric
contaminants.
Minor Surface Dirt – Mildly Aggressive Cleaning
Use of a sponge or bristle brush with a non-abrasive cleaner is recommended. After cleaning, rinse with warm water from a
hose or pressure washer. Towel dry cleaned area and coat area with a high quality wax to provide extra protection.
More Aggressive Cleaning – Removal of Fingerprints or Grease
Repeat processes 1 and 2, then use a hydro-carbon solvent like Acetone or alcohol. As with any hydro-carbon solvent,
caution must be taken when using the product. Do not use in confined spaces or while smoking. Keep solvents out of
contact with hands and skin. Household glass cleaner, Spic nʼ Span are other options for cleaners. After cleaning, towel dry
and apply a coat of high quality wax for extra protection.
Aggressive Cleaning – Removing Stains or Light Rust
If iron contamination or surface staining is suspected, immediately remove the stain or rust using a chrome, brass or silver
cleaner. The use of mild non-scratching creams and polishes are also recommended. When the cleaning procedure is
complete; use a high quality wax for extra protection.
Most Aggressive Cleaning – Removing Heavy Rust Deposits, Iron Contamination, Spot Weld Discoloration and
Weld Spatter using Acid
First try processes 1 through 4. If the stain or rust is not removed, the following should be used as a last resort. Rinse the
surface with hot water. Use a saturated solution of oxalic or phosphoric acid (10 to 15% acid solution). This should be
applied with a soft cloth and allowed to stand for a few minutes – do not rub. This acid should etch out the iron particles.
Follow this with an ammonia and water rinse. Rinse the surface again with hot water; coat with a high quality wax for added
protection. Use extreme caution when working with acids! Synthetic rubber gloves should be used, goggles and aprons are
advisable.
DO NOT USE THIS METHOD IF THE UNIT HAS GALVANIZED STEEL COMPONENTS.
As a minimum, these guidelines should be followed to maintain and clean the stainless steel unit. When cleaning stainless steel,
NEVER use coarse abrasives or steel wool, NEVER clean with mineral acids and NEVER leave stainless in contact with iron or
carbon steel.
For more information on cleaning stainless steel, please request a copy of EVAPCOʼS Engineering Bulletin 40.
For more information on choosing the appropriate grade of stainless steel, please request a copy of EVAPCO's Engineering Bulletin 46.
Cold Weather Operation
EVAPCO counterflow evaporative cooling equipment is well suited to operate in cold weather conditions. The counterflow cooling
tower design encases the heat transfer media (fill) completely and protects it from the outside elements such as wind which can
cause freezing in the unit.
When the evaporative cooling unit is going to be used during cold weather conditions, several items need to be considered. These
include: unit layout, unit piping, unit accessories, and capacity control of the units.
Unit Layout
Adequate unobstructed air flow must be provided for both the intake and discharge from the unit. It is imperative that the equipment
minimize the risk of recirculation. Recirculation can result in condensation freezing the inlet louvers, fans and fan screens. The
buildup of ice on these areas can adversely affect air flow and in more severe cases, lead to failure of these components.
Prevailing winds can create icing conditions on the inlet louvers and fan screens adversely affecting airflow to the unit.
For additional information on unit layout, please refer to EVAPCOʼs Equipment Layout Manual.