Operation_and_Maintenance_Instructions_for_EVAPCO_Water_Cooling_Towers.pdf

Bulletin 113F

For EVAPCO Authorized Parts and Service, Contact Your Local EVAPCO Representative or the Local Mr. GoodTower® Service Provider

AT USS UT LSTE LPTcAT PMTQ

Operation and Maintenance Instructions

FOR EVAPCO INDUCED DRAFT AND FORCED

DRAFT COOLING TOWERS

EVAPCO, Inc. — World Headquarters & Research/Development Center

EVAPCO, Inc. • P.O. Box 1300 • Westminster, MD 21158 USA PHONE: 410-756-2600 • FAX: 410-756-6450 • E-MAIL: marketing@evapco.com

EVAPCO, Inc.

World Headquarters P.O. Box 1300 Westminster, MD 21158 USA Phone: 410-756-2600 Fax: 410-756-6450 E-mail: marketing@evapco.com

EVAPCO Asia/Pacific

EVAPCO Asia/Pacific Headquarters 1159 Luoning Rd. Baoshan Industrial Zone Shanghai, P. R. China, Postal Code: 200949 Phone: (86) 21-6687-7786 Fax: (86) 21-6687-7008 E-mail: marketing@evapcochina.com

EVAPCO Europe

EVAPCO Europe BVBA European Headquarters Industrieterrein Oost 4010 3700 Tongeren, Belgium Phone: (32) 12-395029 Fax: (32) 12-238527 E-mail: evapco.europe@evapco.be

EVAPCO East 5151 Allendale Lane Taneytown, MD 21787 USA Phone: 410-756-2600 Fax: 410-756-6450 E-mail: marketing@evapco.com

EVAPCO Midwest 1723 York Road Greenup, IL 62428 USA Phone: 217-923-3431 Fax: 217-923-3300 E-mail: evapcomw@evapcomw.com

EVAPCO West 1900 West Almond Avenue Madera, CA 93637 USA Phone: 559-673-2207 Fax: 559-673-2378 E-mail: contact@evapcowest.com

EVAPCO Iowa 925 Quality Drive Lake View, IA 51450 USA Phone: 712-657-3223 Fax: 712-657-3226

EVAPCO Iowa Sales & Engineering 215 1st Street, NE P.O. Box 88 Medford, MN 55049 USA Phone: 507-446-8005 Fax: 507-446-8239 E-mail: evapcomn@evapcomn.com

EVAPCO Northwest 5775 S.W. Jean Road, Suite 104 Lake Oswego, Oregon 97035 USA Phone: 503-639-2137 Fax: 503-639-1800

EVAPCO Newton 701 East Jourdan Street Newton, IL 62448 USA Phone: 618-783-3433 Fax: 618-783-3499 E-mail: evapcomw@evapcomw.com

EVAPCO-BLCT Dry Cooling, Inc.

981 US Highway 22 West Bridgewater, New Jersey 08807 USA Phone: 1-908-379-2665 E-mail: info@evapco-blct.com

Refrigeration Valves & Systems Corporation A wholly owned subsidiary of EVAPCO, Inc.

1520 Crosswind Dr.

Bryan, TX 77808 USA Phone: 979-778-0095 Fax: 979-778-0030 E-mail: rvs@rvscorp.com

EvapTech, Inc.

A wholly owned subsidiary of EVAPCO, Inc.

8331 Nieman Road Lenexa, KS 66214 USA Phone: 913-322-5165 Fax: 913-322-5166 E-mail: marketing@evaptech.com

Tower Components, Inc.

A wholly owned subsidiary of EVAPCO, Inc.

5960 US HWY 64E

Ramseur, NC 27316 Phone: 336-824-2102 Fax: 336-824-2190 E-mail: mail@towercomponentsinc.com

EVAPCO Europe, S.r.l.

Via Ciro Menotti 10 I-20017 Passirana di Rho Milan, Italy Phone: (39) 02-939-9041 Fax: (39) 02-935-00840 E-mail: evapcoeurope@evapco.it

EVAPCO Europe, S.r.l.

Via Dosso 2 23020 Piateda Sondrio, Italy

EVAPCO Europe GmbH Insterburger Straße 18 40670 Meerbusch, Germany Phone: (49) 2159-69560 Fax: (49) 2159-695611 E-mail: info@evapco.de

Flex coil a/s A wholly owned subsidiary of EVAPCO, Inc.

Knøsgårdvej 115 DK-9440 Aabybro Denmark Phone: (45) 9824 4999 Fax: (45) 9824 4990 E-mail: info@flexcoil.dk

EVAPCO S.A. (Pty.) Ltd.

A licensed manufacturer of EVAPCO, Inc.

18 Quality Road Isando 1600 Republic of South Africa Phone: (27) 11-392-6630 Fax: (27) 11-392-6615 E-mail: evapco@evapco.co.za

Evap Egypt Engineering Industries Co.

A licensed manufacturer of EVAPCO, Inc.

5 El Nasr Road Nasr City, Cairo, Egypt Phone: 2 02 24022866 /2 02 24044997 Fax: 2 02 24044667/2 02 24044668 E-mail: Primacool@link.net / Shady@primacool.net

EVAPCO (Shanghai) Refrigeration Equipment Co., Ltd.

1159 Luoning Rd., Baoshan Industrial Zone Shanghai, P.R. China, Postal Code: 200949 Phone: (86) 21-6687-7786 Fax: (86) 21-6687-7008 E-mail: marketing@evapcochina.com

Beijing EVAPCO Refrigeration Equipment Co., Ltd.

No. 13 Yanxi Avenue, Yanqi Development Zone Huai Rou County Beijing, P.R. China Postal code 101407 Phone: (86) 10 6166-7238 Fax: (86) 10 6166-7395 E-mail: evapcobj@evapcochina.com

EVAPCO Australia (Pty.) Ltd.

34-42 Melbourne Road P.O. Box 436 Riverstone, N.S.W. Australia 2765 Phone: (61) 2 9627-3322 Fax: (61) 2 9627-1715 E-mail: sales@evapco.com.au

EVAPCO Composites Sdn. Bhd No. 70 (Lot 1289) Jalan Industri 2/3 Rawang Integrated Industrial Park Rawang, Selangor, 48000 Malaysia Phone: 60 3 6092-2209 Fax: 60 3 6092-2210

EvapTech Asia Pacific Sdn. Bhd A wholly owned subsidiary of EvapTech, Inc.

B-6-1, IOI Boulevard Jalan Kenari 5, Bandar Puchong Jaya 47170 Puchong, Selangor Darul Ehsan Malaysia Phone: (60-3) 8070-7255 Fax: (60-3) 8070-5731 E-mail: marketing-ap@evaptech.com

EVAPCO North America

EVAPCO...SPECIALISTS IN HEAT TRANSFER

PRODUCTS AND SERVICES.

Visit EVAPCO’s Website at: http://www.evapco.com

SUN AXS

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Operation and Maintenance Instructions

Table of Contents

Introduction Safety Precautions Initial Storage and/or Idle Period Recommendations International Building Code Provision Initial and Seasonal Start-Up Checklist

General Initial and Seasonal Start-Up Maintenance Checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7 Seasonal Shut-Down Checklist

Basic Cooling Tower Sequence of Operation System Off / No Load System/Condensing Temperature Rises System Temperature Stabilizes System Temperature Drops System Off / No Load Bypass Mode Optional Defrost Cycle

Fan System Fan Motor Bearings Fan Shaft Ball Bearings Fan Belt Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-11 Gear Drives Air Inlet Fan System Capacity Control

Fan Motor Cycling Sequence of Operation for Fan Motor Cycling Two Speed Motors Variable Frequency Drives

Recirculated Water System Routine Maintenance Suction Strainer in Cold Water Basin Cold Water Basin Operating Water Levels Water Make Up Valve Pressurized Water Distribution System Bleed-Off Valve

Water Treatment and Water Chemistry Bleed or Blowdown Galvanized Steel - Passivation Water Chemistry Parameters Control of Biological Contamination Gray Water and Reclaimed Water Air Contamination

Stainless Steel Maintaining the Appearance of Stainless Steel Cleaning of Stainless Steel

Cold Weather Operation Unit Layout Freeze Protection of Recirculating Water Unit Piping Unit Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21-22 Capacity Control Methods for Cold Weather Operation Ice Management

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Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-25 Replacement Parts

Part Identification Drawings AT/USS 4’ Wide Towers AT/USS 6’, 8’ & 8.5’ Wide (per cell) Towers – Side Connection AT/USS 6’, 8’ & 8.5’ Wide (per cell) Towers – End Connection AT/USS 10’, 12’, & 14’ Wide (per cell) Towers – Side Connection AT/USS 10’ & 12’ Wide’ (per cell) Towers – End Connection AT/USS 14’ x 24’ (per cell) Towers – Side Inlet Connection, End Outlet AT/USS 14’ x 26’ (per cell) Towers – End Connection AT/USS 14’ x 26’ (per cell) Towers – Side Connection AT/USS 42’ x 26’ (three cell) Towers – Bottom Inlet Connection, Bottom Outlet AT/USS 56’ x 26’ (four cell) Towers – Bottom Inlet Connection, Bottom Outlet AXS Towers - Single Stack AXS Towers - Double Stack UT 6’, 8’ & 8.5’ Wide (per cell) Towers – Side Connection UT 6’, 8’ & 8.5’ Wide (per cell) Towers – End Connection UT 10’, 12’, & 14’ Wide (per cell) Towers – Side Connection UT 10’ & 12’ Wide (per cell) Towers – End Connection UT 14’ x 24’ (per cell) Towers – Side Inlet Connection, End Outlet UT 14’ x 26’ (per cell) Towers – End Connection UT 14’ x 26’ (per cell) Towers – Side Connection UT 42’ x 26’ (three cell) Towers – Bottom Inlet Connection, Bottom Outlet UT 56’ x 26’ (four cell) Towers – Bottom Inlet Connection, Bottom Outlet SUN 8.5’ Wide Towers - Side Connection SUN 12’ Wide Towers - Side Connection LPT Towers LSTE 4’ & 5’ Wide Towers LSTE 8’ & 10’ Wide Towers PMTQ Towers

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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 27-51 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 in place and secured.

WARNING: Solar panels generate power whenever they are exposed to light. Before performing any type of service or maintenance of the solar array make certain that the Solar Disconnect has been locked in the in the “OFF” position. To fully eliminate power from the panels they should be completely covered with an opaque material.

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 unit’s disconnect, grasping the fan assembly, and rotating it several turns.

• If unit sits longer than a few weeks, run gear reducer (if supplied) for 5 minutes weekly or check sheaves and bushings for corrosion. Scrape and coat with ZRC.

• 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 3 weeks, lubricate the fan shaft bearings and motor adjustment all-thread bolt.

• 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 unit so as not to transmit additional loads to the equipment as a result of seismic or wind forces.

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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 available at www.evapco.com.

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/or 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 manufacturers’ 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. See Pressurized Water

Distribution Section for details. (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 and in proper orientation.

7. Adjust fan belt tension as required. See “Fan Belt Adjustment” section.

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. Manually fill the cold water basin up to the overflow connection.

Seasonal Start up - SUN Cooling Towers

1. Physical damage to a panel – cracked glass, delamination, or corrosion. The panel should be replaced.

2. Shading – trees or modification to neighboring structures can cause shadows on the array. A small shadow may drastically reduce that panels output. If possible remove the source of the shadow.

3. Inverters are continually monitored on the Enlighten web site. The site should be periodically checked to determine that the inverters are performing properly.

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 manufacturer’s maintenance and long term storage instructions for more detailed information. Motors should be serviced in accordance with manufacturer’s instructions.

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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

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

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. Check sheaves and bushings for corrosion. Scrape and coat with ZRC - annually

9. Lubricate fan shaft bearings* – every 1000 hours of operation or every three months

10. Check belt tension and adjust – monthly

11. Sliding motor base – Inspect and grease – annually or as needed

12. Check fan screens, inlet louvers and fans.

Remove any dirt or debris – monthly

13. Inspect and clean protective finish – annually

- Galvanized: scrape and coat with ZRC

- Stainless: clean and polish with a stainless steel cleaner.

14. Check water quality for biological contamination.

Clean unit as needed and contact a water treatment company for recommended water treatment program** – regularly

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.

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OPTIONAL ACCESSORIES:

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

18. SUN Solar Panels – Inspect for damage and clean with hose and soft brush – semi-annually

1. Two or More Days: Energize motor space heaters

– or run motors for 10 minutes twice daily

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 (continued)

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 cold water basin 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 reinstalled.

4. The cold water basin drain should be left open.

5. The fan shaft bearings and motor base adjusting screws should be lubricated. This should also be performed if the unit is going to sit idle prior to start up.

6. The water make up valve needs to be closed. All water make-up, overflow and drain 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 unit’s disconnect is locked and tagged out, and grasping the fan assembly, rotating it several turns.

9. Energize motor space heaters.

See Fan & Pump Manufacturer Maintenance and long term storage instructions for more detailed instructions.

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Basic Cooling Tower Sequence of Operation

System Off / No Load

The system pumps and fans are off. If the basin is full of water a minimum basin water temperature of 40ºF must be maintained to prevent freezing. This can be accomplished with the use of optional basin heaters. See the “Cold Weather Operation” section of this bulletin for more details on cold weather operation and maintenance.

System/Condensing Temperature Rises

The system pump turns on. The unit will provide approximately 10% cooling capacity with only the pump running.

NOTE: If the load is such that simply running the system pump with the unit fan motor idle is sufficient, motor space heaters (if equipped) should be energized while the motor is idle. Alternatively, the motor can be energized twiced daily for a minimum of 10 minutes to protect the motor insulation from damage.

If the system temperature continues to rise, the unit fan is cycled on. For a variable speed controller, the fans are turned on to minimum speed. See the “Fan System – Capacity Control” section of this bulletin for more details on fan speed control options. If the system temperature continues to rise, then the fan speed is increased as required, up to full speed.

NOTE: During sub-freezing weather the minimum recommended speed for variable speed controllers is 50%. ALL FANS IN OPERATING CELLS OF MULTIPLE CELL UNITS MUST BE CONTROLLED TOGETHER TO PREVENT ICING ON THE FANS.

System Temperature Stabilizes

Control the leaving water temperature by modulating the fan speeds with variable speed drives or by cycling fans on and off with single or two-speed drives.

System Temperature Drops

Decrease the fan speed, as required.

System Off / No Load

The system pump turns off. The starter interlock will energize any optional basin heaters in cold weather.

The recirculation pump should not be used as a means of capacity control, and should not be cycled frequently. Excessive cycling can lead to scale build-up, and reduce wet and dry performance.

Bypass Mode

During winter months when cooling load is minimal, bypass mode may be used as a form of capacity control. Bypass mode allows the water to “bypass” the tower’s water distribution system and deposits the inlet water directly into the cold water basin. Alternatively, the incoming water bypass can be piped directly to the return condenser header pipe. Please note: The location of the bypass valve should be 15 feet below the cooling tower cold water basin elevation to assure proper operation and prevent cavitation. This bypass mode should be continued until the total water inventory reaches an acceptable temperature level (usually about 80°F), at which time the bypass may be closed to cause total flow over the fill.

EVAPCO does NOT recommend a partial water bypass due to the potential for freezing the heat transfer media during low ambient operation.

Optional Defrost Cycle

In more severe climates, the incorporation of a defrost cycle may be used to manage the ice formation in and on the unit. During the defrost cycle, the cooling tower fan(s) are reversed at no more than half speed while the system pump flows water through the cooling tower’s water distribution system. Operating the unit in “reverse” will melt any ice that has formed in the unit or on the intake louvers. All multi-speed or VFD duty motors supplied by EVAPCO, whether for standard belt drive or optional gear drive induced draft units, are capable of reverse operation.

Defrost cycles are NOT recommended for forced draft cooling towers. In these units, allowing the leaving water temperature set point to rise causes the fans to be off for very long periods of time, which increases the fan drive component potential for freezing. In lieu of a defrost cycle, forced draft units should be operated at low speed (with a 2-speed motor) or minimum speed (no lower than 25% with a variable frequency drives) in order to maintain positive pressure inside the unit to help prevent ice formation on the fan drive components.

NOTE: MINIMUM CONTROL POINT FOR WATER SHOULD NEVER BE LOWER THAN 42º F.

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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 as shown in Table 1.

Operation and Maintenance Instructions

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: AT/UT/USS Located just beside the fan casing Externally Mounted Motors access door

Induced Draft Units: AT/UT/USS Located inside the fan casing Internally Mounted Motors access door

Induced Draft Units: AXS Located just inside the access door

LSTE Forced Draft Units Located on the front of the unit

LPT Forced Draft Units Located on the front of the unit

PMTQ Located on front of unit

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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 basis. A properly tensioned belt will not “chirp” or “squeal” when the fan motor is started.

Figure 1 – Method 1 Figure 2 – Method 2

On induced draft belt driven units provided with externally mounted motors (4, 6, 8, 8.5, 12, 15 and 17 foot wide units), as shown in Figure 3, LSTE forced draft units, as shown in Figure 4, and PM forced draft units as shown in Figure 7, 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 – LSTE Externally Mounted Motor

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Figure 5 – AT Motor Adjustment

On induced draft belt driven units with internally mounted motors (10, 12, 14, 20, 24, 28, 42 and 56 foot wide units), as shown in Figures 5-6 and LPT units, as shown in Figure 7, 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.

Figure 7 – LPT Motor Adjustment

ADJUSTMENT

NUTS

Figure 8 – PM Style Motor Adjustment

ADJUSTMENT

TOOL

ADJUSTMENT

NUT

Figure 6 – AXS Motor Adjustment

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Gear Drives

Induced draft units with gear drive systems require special maintenance. Please refer to the gear manufacturer’s recommended maintenance instructions. These will be enclosed and shipped with the unit.

Air Inlet

Inspect the air inlet louvers (induced draft units) or fan screens (forced draft units) monthly to remove any paper, leaves or other debris that may be blocking airflow into the unit.

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 (VFD’s). 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 motor’s starter holding coil.

Sequence of Operation for Fan Motor Cycling

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 approximately 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.

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

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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 a standard option from EVAPCO.

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. Select a high quality VFD that is compatible with the fan motor(s) in the EVAPCO unit(s). Many variables in the VFD configuration and installation can affect motor and VFD performance. Two particularly important parameters to consider when choosing and installing a VFD are switching frequency and the distance between the motor and VFD often referred to as lead length. Consult the VFD manufacturer’s recommendations for proper installation and configuration. The motor lead length restrictions can vary with the vendor. Regardless of motor supplier, minimizing lead length between the motor and drive is good practice.The motor lead length restrictions vary with the motor vendor.

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.

Variable Frequency Drive Lock-out Notification

SAFETY PRECAUTIONS:

Qualified personnel should use proper care, procedures and tools when maintaining the Fan/Drive System in order to prevent personal injury and/or property damage.

Identify and Lock-out Harmful Resonant Frequencies

A Variable Frequency Drive (VFD) fan system, unlike traditional fixed-speed systems, is designed to operate between 25% (15Hz) and 100% (60Hz) speeds, which creates an opportunity for operation where resonant frequencies exist. Sustained operation at resonant frequencies may lead to excessive vibration, fatigue of structural components, and/or drive system noise and failure.

Owners and operators must anticipate the existence of resonant frequencies and lock out frequencies during start-up and commissioning in order to prevent drive system operational problems and structural damage. As a part of the normal start-up and commission processes, resonant frequencies should be identified and locked-out in the VFD’s software.

The unit’s supporting structure, external piping, and accessories contribute to the overall harmonic make-up and stiffness of the system. The choice of VFD will also have a significant influence on how the system behaves. Consequently, not all resonant frequencies can be determined in advance at the manufacturer’s factory during final inspection and testing. Relevant resonant frequencies (if they occur) can only be identified accurately after the installation in the system.

To check for resonant frequencies in the field, a run-up and run-down test must be performed. Additionally, VFD carrier frequencies should be adjusted to best align the VFD with the electrical system. Refer to your drive’s start-up procedures for additional information and instruction.

The procedure of checking for resonant frequencies requires stepping through the VFD’s operating range at (2) Hz intervals from the lowest operating frequency to full speed. At each step, pause long enough for the fan to reach steady-state. Note changes in unit vibration during this time. Repeat from full speed to minimum speed. Should vibration-inducing frequencies exist, the run-up and run-down test will isolate the resonant frequencies which then must then be locked-out in the VFD programming.

For more details on the use of variable frequency drives, please download copies of EVAPCO’s Engineering Bulletins 39 and 43 from www.evapco.com.

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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.

STRAINER

ASSEMBLY

ANTI-VORTEXING

HOOD

STRAINER

HANDLE

ANTI-VORTEXING

HOOD

STRAINER

HANDLE

STRAINER

ASSEMBLY

Figure 11 – LSTE/PMTQ Strainer Assembly Figure 12 – LPT Strainer Assembly

Figure 9 – Single Strainer Assembly Figure 10 – Dual Strainer Assembly

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.

ANTI-VORTEXING

HOOD

STRAINER

HANDLE

STRAINER

ASSEMBLY

Figure 13 – AXS Strainer Assembly

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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 14 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 for the mechanical valve should be maintained between 20 and 50 PSIG.

Figure 14 – Mechanical Water Make Up Valve

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 2 for unit specific levels.

Product Line Box OperatingDepth*

AT/UT/USS/SUN 4’ Wide 7”

AT/UT/USS/SUN 14’ Wide & Four Cell Units 11”

AT/UT/USS/SUN All Others 9”

AXS All 9”

LPT All 8”

PMTQ All 13”

LSTE 10’ Wide 13”

LSTE All Others 9” cAT All 9”

Table 2 - Recommended Operating Water Level

* Measured from lowest point on basin floor.

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Figure 15 – LSTE/LPT Water Distribution

Figure 16 – AT/SUN/USS/UT/PMTQ Water Distribution

UNIT

END WALL

THREADED END CAP

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 (LSTE, LPT and PMTQ 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, SUN, USS and UT 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.

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 buildup 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 diffusers have been cleaned, the suction strainer should be checked to make sure it is in good operating condition and positioned properly so that 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 LSTE, LPT models in Figure 15 and as shown in Figure 16 for AT, SUN, USS, UT and PMTQ models. The top of the EVAPCO logo and the nozzle is parallel with the top of the water distribution pipe.

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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.

Water Treatment and Water Chemistry

Proper water treatment is an essential part of the maintenance required for evaporative cooling equipment. A well designed and consistently implemented water treatment program will help to ensure efficient system operation while maximizing the equipment’s service life. A qualified water treatment company should design a site specific water treatment protocol based on equipment (including all metallurgies in the cooling system), location, makeup water quality, and usage.

Bleed or Blowdown

Evaporative cooling equipment rejects heat by evaporating a portion of the recirculated water into the atmosphere as warm, saturated discharge air. As the pure water evaporates it leaves behind the impurities found in the system’s makeup water and any accumulated airborne contaminants. These impurities and contaminants, which continue to recirculate in the system, must be controlled to avoid excessive concentration which can lead to corrosion, scale, or biological fouling.

Evaporative cooling equipment requires a bleed or blowdown line, located on the discharge side of the recirculating pump, to remove concentrated (cycled up) water from the system. EVAPCO recommends an automated conductivity controller to maximize the water efficiency of your system. Based on recommendations from the water treatment company, the conductivity controller should open and close a motorized ball or solenoid valve to maintain the conductivity of the recirculating water. If a manual valve is used to control the rate of bleed it should be set to maintain the conductivity of the recirculating water during periods of peak load at the maximum level recommended by the water treatment company.

Gravity Fed Water Distribution Systems

All induced draft crossflow units (AXS) utilize a water distribution system that relies on gravity to disperse water through the diffusers. Lifting handles are provided on the hot water basin covers to allow access to the water distribution system as shown in Figure 17.

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 hot water basins. The nozzles can be cleared by taking a small pointed probe and moving it back and forth in the diffuser opening; or, by removing the nozzle and cleaning it under a hose.

After the water diffusers have been cleaned, the suction strainer should be checked to make sure it is in good operating condition and positioned properly so that air entrapment does not occur.

Figure 17 – Hot Water Basins

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Water Chemistry Parameters

The water treatment program designed for evaporative cooling equipment must be compatible with the unit’s materials of construction. Control of corrosion and scale will be very difficult if the recirculating water chemistry is not consistently maintained within the ranges noted in Table 3. In mixed metallurgy systems, the water treatment program should be designed to ensure protection of all the components used in the cooling water loop.

Property G-235 Type 304 Type 316 Galvanized Steel Stainless Steel Stainless Steel pH 7.0 – 8.8 6.0 – 9.5 6.0 – 9.5 pH During Passivation 7.0 – 8.0 N/A N/A

Total Suspended Solids (ppm)* < 25 < 25 < 25

Conductivity (Micro-mhos/cm) ** < 2,400 < 4,000 < 5,000

Alkalinity as CaCO3 (ppm) 75 - 400 < 600 < 600

Calcium Hardness CaCO3 (ppm) 50 - 500 < 600 < 600

Chlorides as Cl (ppm) *** < 300 < 500 < 2,000

Silica (ppm) < 150 < 150 < 150

Total Bacteria (cfu/ml) < 10,000 < 10,000 < 10,000

* Based on standard EVAPAK® fill ** Based on clean metal surfaces. Accumulations of dirt, deposits, or sludge will increase corrosion potential *** Based on maximum coil fluid temperatures below 120°F (49°C)

Table 3 – Recommended Water Chemistry Guidelines

Galvanized Steel – Passivation

‘White Rust’ is a premature failure of the protective zinc layer on hot dip or mill galvanized steel which can occur as a result of improper water treatment control during the start-up of new galvanized equipment. The initial commissioning and passivation period is a critical time for maximizing the service life of galvanized equipment. EVAPCO recommends that the site specific water treatment protocol includes a passivation procedure which details water chemistry, any necessary chemical addition, and visual inspections during the first six (6) to twelve (12) weeks of operation. During this passivation period, recirculating water pH should be maintained above 7.0 and below 8.0 at all times. Since elevated temperatures have a harmful effect on the passivation process, the new galvanized equipment should be run without load for as much of the passivation period as is practical.

The following water chemistry promotes the formation of white rust and should be avoided during the passivation period:

1. pH values in the recirculating water greater than 8.3.

2. Calcium hardness (as CaCO3) less than 50 ppm in the recirculating water.

3. Anions of chlorides or sulfates greater than 250 ppm in the recirculating water.

4. Alkalinity greater than 300 ppm in the recirculating water regardless of pH value.

Changes in water chemistry control may be considered after the passivation process is complete as evidenced by the galvanized surfaces taking on a dull gray color. Any changes to the treatment program or control limits should be made slowly, in stages while documenting the impact of the changes on the passivated zinc surfaces.

• Operating galvanized evaporative cooling equipment with a water pH below 6.0 for any period may cause removal of the protective zinc coating.

• Operating galvanized evaporative cooling equipment with a water pH above 9.0 for any period may destabilize the passivated surface and create white rust.

• Re-passivation may be required at any time in the service life of the equipment if an upset condition occurs which destabilizes the passivated zinc surface.

For more information on passivation and white rust, please download a copy of EVAPCO’s Engineering Bulletin 36 at www.evapco.com.

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Gray Water and Reclaimed Water

The use of water reclaimed from another process as a source of makeup water for evaporative cooling…