CROSS FLOW COOLING TOWER OPERATIONS AND MAINTAINENCE MANUAL

Operation and Maintenance Manual


For Cooling Tower & Cooling Towers Preface

The following information is intended to provide instruction, understanding, and includes manufacturer recommendations for maintaining and operating your new LRC-model cooling

tower. Because it takes time to schedule maintenance and servicing after a tower has been damaged, there are steps that the customer can take, to prolong and prevent damage to both their

tower and system as a whole. Please, read through this material and if at any time you have questions relating to our cooling tower, contact us at our corporate office. If proper maintenance is followed and you operate your tower within design parameters, HENGRUN’s LRC-model tower can provide decades of solid operation and performance.

It is recommended that the servicing personnel should study the cooling tower in great detail. Become familiar with the cooling process and the miscellaneous parts within our cooling tower. You will be able to pinpoint problems and potentially solve a problem before it causes shutdown of your cooling tower, which is costly to your application.

1.Motor
2.Fan Stack
3. Speed Reducer
4.Fan
5.Distribution Pan 
6.Distribution System 
7.Louver 
8. Water
9. Air
10. Overflow  
11. Drain 
12. Manual Make -Up  
13. Automatic Make-Up 
14. Outlet 15. Fill

2. STRUCTURE

2.1 FRAME

The frame of your LRC-model cooling tower is either constructed of Hot Dipped Galvanized steel or Stainless Steel, depending on what you specified at time of Purchase. Galvanized steel will provide protection from rusting and corrosion. When the steel is maintained, washed down and kept in good condition, your cooling tower’s structure will remain stableand secure. Stainless-steel material also provides protection from rust and corrosion, and will outlast galvanized steel depending on environmental conditions around your area. Youshould consult the factory to determine which material will be sufficient in your application. F.R.P. (Fiberglass Reinforced Plastic) materials are used in the basin, casing and other sections of the tower. This material will not rust or corrode and has a high tolerance towards chemical exposure. Please consult factory on limitations for certain chemicals to ensure that you do not damage your fiberglass material. If used within the limitations, FRP material provides structural integrity identical to that of Steel and is lighter in weight.

2.2 HEIGHT

HENGRUN’s LRC-model is smaller in height when compared to similar cooling towers. This is beneficial because pump head within the tower is decreased, horsepower is decreased yet

HENGRUN COOLING TOWER CORPORATION OPERATIONS AND MAINTAINENCE MANUAL IS OWNED BY LIANG CHI (USA) CORPORATION. THE NAME “HENGRUN” AND HENGRUN PRODUCT LOGO ARE TRADEMARKS AND ANY REPRODUCTION WITHOUT WRITTEN CONSENT WILL BE A VIOLATION OF LAW AND SUBJECT TO LEGAL ACTIONS. ALL RIGHTS RESERVED, 1998.


identical air volume is achieved, resulting in lower operating costs with identical performance.

2.3 INTERNAL SPACE

The internal structure of your LRC tower is designed to provide maximum working space for repairs and maintenance. A sturdy platform, secured to the frame of the tower is provided for your maintenance team. CAUTION: Due to slimes and algae that may build up the walkway can become slippery. Take Precautions and where proper work boots.

2.4 Fan

The fan of your tower is designed to provide sufficient airflow at lower fan motor RPM and operate at a lower decibel level.

2.5 Fill Materials

Fill material is made of PVC stiff sheets, which are formed by vacuum molding, differing from standard materials used. This material has been tested both in laboratories and applications, to perfection, enabling maximum water surface exposure, allowing for maximum heat transfer.

2.6 Distribution System

LRC towers utilize gravity flow to distribute water evenly over fill material. Hot water entering the tower is dispersed into a distribution pan located on top of the cooling tower next to louvers. The hot water drops through the distribution pans that have predrilled and predetermined hole placement to ensure that water is covering the entire fill media. This form of distribution helps reduce pump size, friction loss, psi requirements, while providing even distribution. The distribution plate within the pan helps slow water flow so that the heattransfer can begin immediately.

3.1   INSTALLATION

3.1 CAUTIONS FOR INSTALLATIONS

A.Pick a location in which airflow is steady and free of structures, which may lower efficiency.

B. Location should be relatively free of dust, acids, and other material, which could build up in your tower and lower efficiency or damage the unit.

C.Keep the tower away from heat sources because these units raise the surrounding air temperature, which will affect your cooling tower’s efficiency. (If this cannot be avoided, an atmosphere temperature should be taken and provided to the factory for recalculation).

D.Provide enough space for piping.

E.Be sure to keep the tower vertical when lifting or mounting to foundation. Once on foundation, anchor bolts and legs of tower should be fastened tightly.

F.The design of the cooling tower is to pull air through the air inlets (louver sides). Be sure that proper space is provided between the tower and an obstacle if structure free areas are not allowable. SEE TABLE BELOW

HENGRUN COOLING TOWER CORPORATION OPERATIONS AND MAINTAINENCE MANUAL IS OWNED BY LIANG CHI (USA) CORPORATION. THE NAME “HENGRUN” AND HENGRUN PRODUCT LOGO ARE TRADEMARKS AND ANY REPRODUCTION WITHOUT WRITTEN CONSENT WILL BE A VIOLATION OF LAW AND SUBJECT TO LEGAL ACTIONS. ALL RIGHTS RESERVED, 1998.


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LRC MODEL

DISTANCE FROM STRUCTURES (i.e.,
Buildings, etc..)

80 ~

125

More Then 6.5 Feet

150 ~

200

More Then 8 Feet

225 ~

350

More then 9.5 Feet

400 ~

600

More Then 10.5 Feet

700 ~

800

More Then 13 Feet

900 ~ 1250

More Then 16.5 Feet

3.2   Pump and Piping

A.  Regarding the piping illustration for cooling tower, please refer to the following chart:

B. When doing the piping work, diameter and length of the inlet pipe rigged on the two sides of the hot water basin should be matched accordingly. Flow Control valves should be installed.

C. The pipe diameter should also match the water flow of tower design.

HENGRUN COOLING TOWER CORPORATION OPERATIONS AND MAINTAINENCE MANUAL IS OWNED BY LIANG CHI (USA) CORPORATION. THE NAME “HENGRUN” AND HENGRUN PRODUCT LOGO ARE TRADEMARKS AND ANY REPRODUCTION WITHOUT WRITTEN CONSENT WILL BE A VIOLATION OF LAW AND SUBJECT TO LEGAL ACTIONS. ALL RIGHTS RESERVED, 1998.


4. reparations Before Operations

4.1 Irrelevant objects by the air inlet or surrounding the fan stack should be removed.

4.2 Be sure that Fan blade will not make contact with Fan stack so as to avoid damage to tower. 4.3 Check to see if the V-Belts of Speed Reducer are properly adjusted.

4.4 V-Belts have to be positioned on the same level.

4.5 After the above checks have been made, switch the fan motor on and off intermittently to see if the fan revolves correctly. At this time you can also check for any abstract noises or vibrations.

4.6 Clean dust and dirt from inside the cold water basin and then fill basin to the overflow level.

4.7 Remove all foreign objects and materials from the Hot water dis tribution pans on top of cooling tower.

4.8 Turn Centrifugal Pump on and off intermittently to remove air from pipes and allow water to fill the system.

4.9 When the pump is in normal operation water level will decrease depending on length of run and actually flow rates required. Float Valve should be adjusted at this point to ensure design

HENGRUN COOLING TOWER CORPORATION OPERATIONS AND MAINTAINENCE MANUAL IS OWNED BY LIANG CHI (USA) CORPORATION. THE NAME “HENGRUN” AND HENGRUN PRODUCTLOGO ARE TRADEMARKS AND ANY REPRODUCTION WITHOUT WRITTEN CONSENT WILL BE A VIOLATION OF LAW AND SUBJECT TO LEGAL ACTIONS. ALL RIGHTS RESERVED, 1998.


cold water temperature is being met, flow rate is adequate and all pipe connection are safely submerged.

5. Power System

5.1 Connect the wires according to wire diagram.

5.2 Re-identify the switches for power system, check if the fuse and connecting wires match with the motor horsepower and avoid single-phase revolution.

6.   Starting

6.1 Start and stop Fan motor, checking to see if motor revolves in the specified direction or if abnormal vibrations or noises begin. If so, shut down the unit and contact HENGRUN for recommendations.

6.2 Check if the Fan Motor is receiving correct voltage and is constant. It is recommended that a vibration switch be used to prevent excessive vibration as a result of fan imbalance or other problems which can generate vibration

6.3 Adjust the water flow with control valves to keep water level of hot water basin between 2~3 inches high.

6.4 Check to be sure desired water level in cold water basin remains constant.

7. Cooling Tower Operation.

7.1 After five to six days of operation, check V-Belts once more to be sure that they have not loosened. If they have, retighten these belts to avoid reduction in fan blade speed and to prevent damage to reducer.

7.2 The circulation water should be replaced at this time to rid system of dirt and debris and to prevent blockage of piping.

8. Routine Maintenance

Please consult a water treatment specialist to verify percentage of bleed that should be established on your system. This will be dependent upon the level of calcium, chlorine, and other minerals within your water supply. Be sure to check hot water and cold water basins on a regular basis and clean any debris that is found within these sections of the tower. This will increase the life of your cooling towers because water quality is one of the major reasons behind tower efficiency and structural integrity. Also make a habit of checking V-Belts, Dispersion holes and fill material to make sure no blockage is occurring. If so, these units can be cleaned using garden hose nozzles or which simple items like a screwdriver.

9.Seasonal Shutdown

9.1 Loosen the V-Belts located within the speed reducer and lubricate bearings.

HENGRUN COOLING TOWER CORPORATION OPERATIONS AND MAINTAINENCE MANUAL IS OWNED BY LIANG CHI (USA) CORPORATION. THE NAME “HENGRUN” AND HENGRUN PRODUCT LOGO ARE TRADEMARKS AND ANY REPRODUCTION WITHOUT WRITTEN CONSENT WILL BE A VIOLATION OF LAW AND SUBJECT TO LEGAL ACTIONS. ALL RIGHTS RESERVED, 1998.


9.2 All circulating water should be drained and disposed of or placed within a holding tank to prevent damage to piping during winter months in which temperatures will drop below freezing.

9.3 Before restarting cooling tower, be sure that all parts are intact and that nothing is obstructing movable parts which could result in damage. If needed, contact HENGRUN our your local service representative to perform an inspection on the cooling tower.

10. Cooling Tower Performance

Flow rates and water level along with the wet bulb, hot water, and cold water temperatures are the major factors in cooling tower performance. If performance appears to have increased or decreased during life of tower, consult the chart below to find possible reasons. If these reasons are not applicable, contact HENGRUN for a consultation.

Causes of Increase                                                                          Cause of Decrease

1.   The heat load has increased.                                                    1. The heat load has decreased.

2.  Circulating water has decreased.                                                  2. Circulating Water has Increased.

3.   The difference between inlet water temperature                            3. Difference between Inlet and Wet and wet-bulb has increased.                                                                                        

4. Low inlet water Temperature when entering tower.

The addition or removal of equipment will affect heat loads. It is important to know what the capacity limitations of your cooling tower is to ensure that you do not adversely affect the performance of the Cooling Tower. It is impossible to get a normal temperature reading at one particular instance because weather conditions throughout the day can affect tower cooling. A series of days in differing conditions should be used to determine an average that will constitute the best determination. In plain, on hot days cooling tower efficiency may decrease, on cold days, cooling tower performance will increase.

The addition or removal of equipment also affects flow rates. In addition, flow rates can be affected by pipe blockage or clogging. It is important to keep your pipelines free of debris and to obtain good water treatment that will limit algae, slimes and calcium build-ups. This will also increase the life ofyour equipment.


Trouble-Shooting Table

Trouble

 

Causes

 

Solutions

Noises

1.

Loose Bolts

1.

Retighten bolts

And

2.

Fan Blade tip making contact with

2.  

Shut Down, Adjust Motor

Vibrations

 

fan stack

 

Base to provide equal

 

3.  

Fan Not Balanced.

 

clearance between fan stack

 

4.  

Bearing Malfunction.

 

and fan.

 

5.  

Motor Malfunction.

3.

Adjust pitches to equalize

 

6.

Speed Reducer

4.

Replace bearings.

     

5.

Rewind or replace motor.

     

6.

Check reducer, make sure well oiled/greased, check v- belts to be sure they are tight.

Power Overloads

1.

Excessive drops in Voltage

1.

Check power supply.

 

2.

Improper fan blade angle.

2.  

Adjust pitches to

 

3.  

Motor malfunction

 

recommended settings

     

3.

Replace motor

Rise in water

1.

Decrease in water flow.

1.

Check water pump and

temperature

2.

Drop in water level of basin or

 

pipes for blockage.

   

distribution pans.

2.  

Clean distribution pans and

 

3.  

Decrease in air flow

 

check float valve.

 

4.  

Blockage of inlet louvers

3.

Check fill material for blockage, check reducer v-belts, check motor.

     

4.

Remove debris, be sure louvers are equal distance apart.

Drop in Water Flow

1.

Blockage of Strainer

1.

Remove and clean strainer.

 

2.

Water basin level decreases

2.  

Adjust float valve.

 

3.  

Inadequate water flow from pump

3.

Check pump seals and connections.

Water carry-over

1.

Excessive Water Flow

1.

Adjust water flow rate

 

2.

Unevenness of water volume in distribution basin.

 

through pumps or with flow valves.

 

3.

Excessive air flow.

2.  

Clean distribution pan.

     

3.  

Adjust fan blade pitches to reduce drift loss.

11.0 CALCULATION OF MAKE-UP WATER

The gradual loss of circulating water during operation is caused by the following factors:

A.      During heat exchange, the contact of cold air and hot water will generate an evaporation loss due to moisture absorption into air flow. This is known as evaporation loss, which is how heat exchange is accomplished.

B. As air volume increases the driving force of this current overcomes the gravitational flow of water fall and causes a small amount of water to be carried out of the tower.

C.       When the water is circulating for a long time, solids build up and as this concentration increases it becomes vital to “bleed” a certain amount of water from the tower which is known as a bleed loss. This will prevent buildup of contaminants which can affect tower structure.

11.1 Calculating Evaporation Loss

HENGRUN COOLING TOWER CORPORATION OPERATIONS AND MAINTAINENCE MANUAL IS OWNED BY LIANG CHI (USA) CORPORATION. THE NAME “HENGRUN” AND HENGRUN PRODUCT LOGO ARE TRADEMARKS AND ANY REPRODUCTION WITHOUT WRITTEN CONSENT WILL BE A VIOLATION OF LAW AND SUBJECT TO LEGAL ACTIONS. ALL RIGHTS RESERVED, 1998.


E = Q/1000 = (T1-T2) / 1000 x L

E= Evaporating Water    GPM

Q= Heat Load     BTU/Hr

1000 = Water Evaporation Heat BTU/Hr

T1= Inlet Water Temperature  oF

T2= Outlet Water Temperature   oF

L= Circulating Water Flow   GPM

11.2 The Loss Of Carry-Over

The loss of Carry-over depends on the cooling tower design, and Air Velocity. Generally speaking, the loss is equal to 0.2% to 0.3% of total circulation water.

11.3   The Loss of Regular Blow-Down

To decrease the loss of blow-down, please follow the procedures below:

A.  Open the drain on the hot water basin while the cooling tower is in operation.

B.   Increase the operational water level to anticipate the water flowing out of the overflow outlet

C.  Replace the water in the cold water basin and pipes annually.

The water quality and its concentration of solids will determine the loss of regular blow-down. Generally speaking, the loss is about 0.3% of total circulating water.

 11.4  Make-up Water Calculation

The total make-up water of circulating water is equal to: M = E + C + D

M = Make-up Water                              E = Evaporation Loss

C = Carry-over                                   D = Regular Blow-down Loss

When the cooling tower is rigged to an air-conditioner, the cooling range is set at 10 oF. In this case, the make -up water needed for the cooling tower is about 2% of the circulation water.