Marley 500 Industrial CrossFlow Cooling Tower Operation and
Contents
1. rate to avoid surges or water hammer which could damage the distribution piping Circulate water over the tower continuously for several days before starting the me chanical equipment and putting the tower into continuous operation INSPECTION It is imperative that all operating assemblies be inspected before they are placed in operation Following is a list of components to be checked before starting the tower 1 Check drive shaft alignment Realign if necessary See Marley Drive Shaft Service Manual Check tightness of bolts that attach steel mechanical equipment support to the tower framing Check tight ness of bolts in fan cylinder joints and fan cylinder anchorage Do not pull washers into the wood Check tightness of bolts at diagonals and columns and at girts and columns in the area between fan and cold water basin Check tightness of the following bolted joints in the fan and drive assemblies a Fan hub clamp bolts see Marley Fan Service Manual for correct torque setting Fan hub cover bolts c X Geareducer and motor mounting bolts d Drive shaft coupling and guard bolts Check Geareducer oil for water accumulation by draining off and testing a sample as outlined in the Geareducer Service Manual Check Geareducer oil b level at oil level mark on the side of the case Add oil as required The oil level placard must be adjusted so its full mark is at the same elevation as the full mark on2. 8 38 25 18 11 08 06 10 15 20 25 EXAMPLE 7000 GPM circulating rate 15 cooling range To maintain 4 concentrations the required blowdown is 38 or 0038 times 7000 GPM which is 26 6 GPM f tower is operated at 4 concentrations circulating water will contain four times as much dissolved solid as the makeup water providing none of the solids form scale or are otherwise removed from the system CHEMICAL TREATMENT In some cases chemical treat ment of the circulating water is not required if adequate blowdown is maintained in most cases however chemical treatment is required to prevent scale formation and corro sion Sulfuric acid or one of the polyphosphates is most generally used to control calcium carbonate scale Various proprietary materials containing chromates phosphates or other compounds are available for corrosion control When water treatment chemicals are required the services of reli able water treating companies should be obtained Slime a gelatinous organic growth and algae a green moss may grow in the cooling tower or heat exchangers Their presence can interfere with cooling efficiencies Proprietary compounds are available from water treating companies for the control of slime and or algae however compounds which contain copper must be used with care Copper can accelerate corrosion of steel iron aluminum and galvaniz ing and should not be used in systems containing any of those ma
3. MANUAL Class 500 Industrial CROSS FLOW COOLING TOWERS Operation and Maintenance Instructions APRIL 1980 5800 Foxridge Drive P O Box 2912 Mission Kansas 66201 M92 1315 Sua3MO4 00S SSV19 JONVNIANIVIN ONV NOIL VU3dO TABLE OF CONTENTS cl 00 0 aise ote be eve ale ele Sa Gre ee Se eS 8 Pre Starting Procedure o o 6 wee alien Tower Trouble Tips 2 2 ee ee ee te etn o 88 Transverse Cross Section Class 500 Double Flow Tower era 10 Cooling Tower Inspection Check List PE PE 11 INDUSTRIAL CROSS FLOW COOLING TOWERS Class 500 Towers Operation and Maintenance Instructions GENERAL These instructions will assist in obtaining efficient long life from Marley cooling equipment Direct questions concern ing tower operation and maintenance to your Marley sales office or representative Always include your tower serial number when writing for information or ordering parts Look for this number on the nameplate near the access door PRE STARTING PROCEDURE CLEANING Remove any dirt and trash which has accumu lated in the hot water distribution basins Clean any noz zles that are clogged Remove any sediment from the cold water basin sump and screens Use a water hose to flush cold water basins OPERATE WATER SYSTEM Completely open all hot water flow control valves Start the circulating water pumps Increase the flow of circulating water gradually to design water
4. TOWER COMPANY Health Alert Among other sources outbreaks of Legionnaires Disease have reportedly been traced to cooling towers Maintenance procedures that prevent amplification and dissemination of Legionella and other airborne bacteria should be formulated and implemented BEFORE systems are operated and continued regularly thereafter to avoid the risk of sickness or death The following is recommended A Do NOT attempt any service unless the A Drift eliminators should be inspected fan motor is locked out monthly Any debris or scale should be cleaned off the eliminators when noted Replace any damaged or worn out Q New cooling towers should be cleaned and treated with biocides by a water treatment expert before startup See your components Cooling Tower User Manual for more Q Workers cleaning units should use detailed instructions on biocidal protective clothing and equipment during treatment decontamination Q Ata minimum cooling towers shouldbe Although using these practices will not cleaned and disinfected with biocides guarantee that a system or individual twice a year Systems with biofouling or component will not be contaminated by positive cultures of legionella may require legionella they should reduce the chance additional cleaning of colonization A Units should be inspected weekly for For additional copies of the tower User bacterial growth and general operating Manual or other literature pertaining to condit
5. e bad bearings Check voltages and currents of all three lines Correct if required Check and correct bracket fits or bearing Rebalance Reinstall or replace fan d Check voltage and current of all three lines against nameplate values Check fan blade pitch See Fan Service Manual Check for drag in fan drive train as from damaged bearings Check nameplate against power supply Check rpm of motor and gear ratio Remove grease reliefs Run motor up to speed to purge excessive grease If not poor machining replace worn bearing Change to proper lubricant See motor manufacturer s instruc tions Stop motor and attempt to start it Motor will not start if single phased Check wiring controls and motor Clean motor and check ventilation openings Allow ample ventil ation around motor Check with Ohmmeter TROUBLE Motor Runs Hot continued Motor Does Not Come Up To Speed Wrong Rotation Motor Geareducer Noise Unusual Fan Drive Vibration Fan Noise TOWER TROUBLE TIPS CAUSE Insufficient grease Deterioration of or foreign material in grease Bearings damaged Incorrect fan blade pitch Voltage too low at motor terminals because of line drop Broken rotor bars Wrong sequence of phases Geareducer bearings Gears Loose bolts and cap screws Unbalanced drive shaft or worn couplings Worn Geareducer bearings Unbalanced motor Bent Geareducer shaft Loose fan hub c
6. e distribution pip ing some seepage at edge joints may occur during pre start up and in the initial stages of operation After the first two weeks of continuous operation check tightness of nuts se curing GRP pipe bands on the redwood stave pipe Nuts should be snug Do not over tighten Clean the sump screens several times during the first weeks of operation After this clean sump screens as required STARTING THE FAN Start the fan After 30 minutes operation time to permit Geareducer oil to come up to operating temperature check motor load with watt meter or take operating volt and ampere readings and calculate motor HP Refer to Marley Fan Service Manual for instruc tions Pitch fans to pull correct contract horsepower when circulating design water rate at design hot water tempera ture OPERATION TOWER PERFORMANCE Keep the tower clean and the water distribution uniform to obtain continued maximum cooling capacity Do not allow excessive deposits of scale or algae to build up on the filling or eliminators Keep the metering orifices free of debris to assure correct distribu tion and cooling of water The capacity of a tower to cool water to a given cold water temperature varies with the wet bulb temperature and the heat load on the tower As the wet bulb temperature drops the cold water temperature also drops However the cold water temperature does not drop as much as the wet bulb temperature A tower does not contr
7. ection of wind circulating water rate and heat load Excessive ice formation may be con trolled by regulating air and water flow through the tower by one or more of the following procedures 1 Shut the fan down This reduces the cooling rate to a minimum and increases the quantity of warm water on the louvers to a maximum Except for extreme cold conditions or extended freezing conditions this procedure will normally control ice formation For automatic operation a timer switch can be provided to shut the fan down for a few minutes each hour If the tower has two speed motors operate the fan at half speed forward This reduces the cooling rate heat transfer and increases the quantity of warm water on the louvers Under extended extreme cold conditions it may be necessary to operate the fan in reverse This forces warm air out through the louvers melting any accum ulated ice Reversal may be at either full or half speed however full speed is recommended if adequate heat load is available Reverse operation of the fan should only be used to control ice not prevent it Reverse fan operation should not exceed 15 to 20 minutes Usually much less time than this is required to melt accumulated ice With no heat load on the circulating water icing can not be controlled effectively by air control during freezing weather Towers must not be operated with reduced water rate and or no heat load during freez ing weather If a by pass directl
8. ions Bacterial growth should be this unit please contact your Marley reported to your water treatment expert sales representative for immediate attention 4 Marley Marley Cooling Technologies 7401 W 129 Street Overland Park Kansas 913 664 7400 Cooling Technologies Manual 99 1342
9. load and operate motor If motor still vibrates re balance rotor Check fan and pinion shafts with dial indicator Replace if necessary Tighten hub cover fasteners Adjust cylinder to provide blade tip clearance Check and tighten if necessary NOILO3S SSOYI 3SYIASNVYHL SUO 193NNOD TWYNLINYIS SuOHOMV 1YWODVIG SH3H10 mo NIS V8 31382802 A NoT ec d n av Pm CAT 031v90uu05 cn ani ES d S3u01VNIMI13 Estate en PETT TAM 3NO89NIMU3H Goons ariana inanitia inae eE Su3AN07 031v9mmnio2 YILINIVIS 03010M MOLLDIMN WOLLMAN ASIC BIOKITAD NVJ du xo8 WOLLNGIYLSIG G3Y3A0D anit HO 1132 HWI Mond uv 30 38N 1431832 3Su3ASNYSN NO u32003uv39 ATTUVN 034100 3010N 1Y0dd MS G3ZILINA 38n1 3N0WO1 INM 1103 TVANVH 934 NWS 30V19 1 110N A310VW 13YHS3AIUQ A3 TUN 33g0v1 Nld 3dAL M 03010 NOI L23fNI 10 COOLING TOWER INSPECTION CHECK LIST Route to Owner Date Inspected Plant Inspected By Location Tower Manufacturer Owner Designation Installed 19 Water Treatment Used Model No Design GPM cues oW Condition 1 Good 2 Repair 3 Replace OAAR Condition 1 Good 2 Repair 3 Replace f1 21 3 EXTERIOR STRUCTURE ERES MECHANICAL EQUIPMENT NE 1 Endwall Casing amp Access Doors 23 Drive Shafts Type 2 Louvers 24 Speed Reducer ean 3 Drain Boards BR Series Ratio 4 Stairway fe el Oil Level EA 5 Fan Deck a Oil Seal
10. m is picked up by air being pulled through the tower and dis charged out the fan cylinders Avoid operation of fans until the foaming is controlled SPARE PARTS Marley maintains a stock of replacement parts for mechani cal equipment Shipment of these parts is normally made within ten days after an order is received If emergency ser vice is necessary contact the local Marley sales office or representative for assistance To prevent prolonged shutdown periods in case of damage to the mechanical equipment it is suggested that the follow ing spare parts be carried in the owner s stock 1 One fan assembly 2 One Geareducer assembly 3 One drive shaft assembl y Be sure to furnish the tower serial number when ordering any parts SEASONAL SHUTDOWN INSTRUCTIONS BASIN AND FRAME Drain the tower basins and all exposed piping Leave the cold water basin drain open Water may be left in wood cold water basin if tower is located in a non freezing area During shutdown clean the tower and make any necessary repairs Apply protective coating as required to all metal parts Particular attention should be given to mechanical equipment supports drive shafts and drive shaft guards In spect visually for wood deterioration and test members for soft spots Protect wood towers against fire If tower is wetted for fire protection wet it down continuously alternate wetting and drying is destructive to wood CAUTION If ambient tempera
11. maintenance may be desirable FAN amp FAN GUARD Inspect for clogging Check for unusual noise or vibration Inspect keys keyways and set screws Make sure vents are open Lubricate grease Check oil seals Check operating oil level Check static oil level o 0 00 PF WORD Check oil for water and sludge E oO Change oil at least Check fan blade tip clearance Check water level Check for leakage Inspect general condition Tighten loose bolts Clean Repaint Rebalance Completely open and close 20 Inspect repair for safe use El PPP tet TT tt bp 21 Inspect and repair before each use DRIVESHAFT amp GUARDS fele wor UNIT MAINTENANCE Well maintained equipment gives the best operating results and the least maintenance cost Marley recommends setting up a regular inspection schedule to insure effective safe operation of the cooling tower Use the schedule in Table to obtain continuously good performance with least tower maintenance See Cooling Tower Inspection Check List in this manual Keep a continuous lubrication and mainte nance record for each cooling tower Regular inspection and repair of personnel safety items indicated by an aster isk in Table and a record of same is especially important SAFETY FIRST For a supply of check list forms con tact your Marley sales office or representative HOT WATER DISTRIBUTION BASINS Metering orifices i
12. n the floor of the hot water basin may be cleaned without shutting down any part of the tower Remove dirt algae leaves etc which might get in these basins or orifices The metering orifices must be kept in place to assure proper SUCTION SCREEN water distribution Completely open and close flow control valves at least semiannually to remove any scale on the threads Grease the stainless steel stem to prevent scale forming Lubricate the valves at least semi annually with a lithium base NLGI No 2 consistency grease More frequent relubrication of valves and valve stems may be dictated by circulating water conditions COLD WATER COLLECTING BASIN Inspect collecting basin occasionally for leaks and repair if necessary Minor leaks may appear in redwood basins when starting with a dry basin but these generally disappear after the wood be comes soaked Keep cold water outlets clean and free of debris Make up and circulating water controls must oper ate freely and maintain the desired water quantity in the system TOWER FRAMEWORK Keep framework bolts tight Pay particular attention to bolts in the mechanical equipment supports Do not pull washers into the wood DRIVE SHAFT Check drive shaft alignment and condition of couplings every six months See the Drive Shaft Service Manual for correcting misalignment balancing or replacing parts ELECTRIC MOTOR Lubricate and maintain each electric motor in accordance with the manufacture
13. ol the heat load The quantity of water circulated determines the cooling range for a given heat load The hot and cold water temperature increases with higher heat loads COLD WATER COLLECTING BASIN The normal water depth in a wood basin is 5 inches while in a concrete basin the normal water level is 8 to 13 inches below the curb Adjust the make up water supply to maintain this water level Low operating depths of the water require air baffles under the fill to prevent air bypass Maintain sufficient water depth to prevent cavitation HOT WATER DISTRIBUTION SYSTEM Keep metering orifices clean and in place in distribution basins Adjust water flow to give the same depth in the distribution basins of all cells Design water depth varies from 3 to 5 depend ing upon design circulating water rate If a major change in the quantity of water to be circulated over the tower is to be made replace the removable metering orifices with ones of the new correct orifice size to provide adequate water break up and maintain the proper water level If an Amertap condenser tube cleaning system is part of plant equipment care should be taken during operation to back wash the strainer section only after the sponge rubber cleaning balls are removed from the system by trapping them in the collector If the balls are allowed to enter the cooling tower supply piping they can clog the plastic meter ing orifices Clogged orifices will cause unequal wate
14. otor Noise Motor Runs Hot TOWER TROUBLE TIPS Power not available at motor terminals CAUSE Wrong connections Low voltage Open circuit in motor winding Motor or fan drive stuck Rotor defective Motor running single phase Motor leads connected incorrectly Ball bearings Electrical unbalance Air gap not uniform Rotor unbalance Cooling fan hitting guard Wrong voltage or unbalanced voltage Overload Wrong motor rpm Bearings overgreased Rotor rubs stator bore Wrong lubricant in bearings One phase open Poor ventilation g8 Winding fault REMEDY Check power at starter Correct any bad connections between the control apparatus and the motor Check starter contacts and control circuit Reset overloads close contacts reset tripped switches or replace failed control Switches If power is not on all leads at starter make sure overload and short circuit devices are in proper condition Check motor and control connections against wiring diagrams Check nameplate voltage against power supply Check voltage at motor terminals Check stator windings for open circuits Disconnect motor from load and check motor and Geareducer for cause of problem Look for broken bars or rings Stop motor and attempt to start it Motor will not start if single phased Check wiring controls and motor Check motor connections against wiring diagram on motor Check lubrication Replac
15. over Blade rubbing inside of fan cylinder Loose bolts in blade clamps REMEDY Straighten or replace shaft Remove plugs and regrease bearings Flush bearings and relubricate Replace bearings See Fan Service Manual for blade pitching instructions Check transformer and setting of taps Use higher voltage on transformer terminals or reduce loads Increase wire size or reduce inertia Look for cracks near the rings A new rotor may be required Have motor service man check motor Change any two of the three motor leads If new see if noise disappears after one week of operation Drain flush and refill Geareducer See Geareducer Service Manu al If still noisy replace Correct tooth engagement Replace badly worn gears Replace gears with imperfect tooth spacing or form Tighten all bolts and cap screws on all mechanical equipment and supports Make sure motor and Geareducer shafts are in proper alignment and match marks properly matched Repair or replace worn couplings Rebalance drive shaft by adding or removing weights from balancing cap screws See Drive Shaft Service Manual Be sure blades are properly positioned in correct sockets Check match numbers Make certain all blades are as far from center of fan as safety devices permit All blades must be pitched the same See Fan Service Manual Clean off deposit build up on blades Check fan and pinion shaft endplay Replace bearings as necessary Disconnect
16. plenum areas of the tower One of the best methods of inspection for pocket rot is sounding with hammer blows Members which have pocket rot sound dead while non rotted members have a ring or live sound Areas which sound dead can be probed with a screwdriver or other pointed tool to verify the presence of pocket rot Marley maintains a laboratory for detailed wood inspections and has personnel on its staff experienced in all aspects of wood deterioration and preservative treatment In addition several Marley publications are available which give detailed information on the subject of wood deterioration and treat ment Contact the nearest sales office or representative for more information about wood inspection services and for copies of the publications WATER TREATMENT BLOWDOWN Blowdown or bleed off is the continuous removal of a portion of the water from the circulating sys tem Blowdown is used to prevent the dissolved solids from concentrating to the point where they will form scale T he amount of blowdown required depends upon the cooling range the difference between the hot and cold water tem peratures and the composition of the make up water water added to the system to compensate for losses by blowdown evaporation and drift The following table shows the amount of blowdown required to maintain differ ent concentrations with various cooling ranges BLOWDOWN OF CIRCULATING RATE RANGE F 5 7
17. r s instructions If repair work is necessary contact the nearest representa tive of the motor manufacturer See Warranty Section of Marley Service Manual on Electric Motors FAN Inspect fan blade surfaces every six months For de tailed maintenance information refer to Marley Fan Service Manual GEAREDUCER Make weekly and monthly oil checks In spect internal parts during seasonal oil change Refer to the Geareducer Service Manual for detailed maintenance in structions PAINTING Periodically clean and if necessary recoat all metal parts subject to corrosion COOLING TOWER WOOD DETERIORATION Untreated wood in cooling towers can be damaged by decay anytime after the first year or two of service If decay is discovered and treated in its early stages serious wood damage can be prevented Routine inspections should be made to assure that decay is discovered before it is heavily advanced Decay is commonly of two very general types soft rot and pocket rot Soft rot is easier to detect because it is almost always on the surface of wood members It makes the sur face soft and weak and in its more advanced stages the de cayed wood can be easily removed This type of rot occurs primarily in the flooded areas of the tower Pocket rot as the name implies occurs in pockets inside of the wood members For this reason it is more difficult to detect than is soft rot Pocket rot is most commonly found in the heavi er members in the
18. r distri bution over the fill which will affect thermal performance Extensive clogging can lead to overflowing the distribution Wet bulb temperature the temperature indicated by the wet bulb thermometer of a sling or mechanically aspirated psychrometer Cooling range the temperature difference between the hot water coming into the cooling tower and the cold water leaving the tower basins and possible ice damage to towers installed in freez ing climates The basins should be frequently checked for orifice clogging until such time as the operation sequence of the Amertap system assures that no balls enter the cool ing tower piping FAN DRIVE If a two speed motor is used allow a time de lay of a minimum of 20 seconds after de energizing the high speed winding and before energizing the low speed winding Tremendous strains are placed on driven machinery and motor unless the motor is allowed to slow to low speed rpm or less before the low speed winding is energized When changing fan direction of rotation allow a minimum of two minutes time delay before energizing the fan motor WINTER OPERATION During periods of low temperature operation 35 to 40 F or below ice will form on the rela tively dry parts of the tower that are in contact with the in coming air Primarily this includes the louvers and adjacent structural framing Ice forming characteristics on any given tower will vary de pending on velocity and dir
19. s ama 6 Fan Deck Supports a Vent ae T 7 Handrails jJ Back Lash 5 B Ladders amp Walkways EAST Pinion Shaft Play E 9 Distribution System USE IRI Fan Shaft End Play E o Headers Type ae en Last Oil Change Date eee Distribution Basin ze Oil Used Sp Water Level i E 25 Fans fee Flow Control Valves Size p Dia Type Nozzles Size ans Hub 1 Waiter Distribution ES Blades 10 Spray System amp Spray Nozzles HE Hub Cover Estrato 11 Fan Cylinders Type SAP Tip Clearance Ee INTERIOR STRUCTURE NEN No Vibration Vibration Oid 12 Fill Type Additional Components If installed on tower IH 13 Columns mE DE Fan Guards 14 Girts p pes Oil Gauge amp Drain Lines mE i ie 15 Diagonals eae A Vibration Limieswltenes 16 Partitions amp Doors be ilis qs Other 17 Eliminators Type Ao 3 3 a 18 Walkway ae a 19 Cold Water Basin Type RE Water Depth EE 26 Motor Mfr ERE i 20 Mech Equip Support Type BEEN Name Plate HP RPM HANDLING EQUIPMENT FEE Phase Cycle Volts 21 Davits Derricks amp Hoists Amperes Frame 22 Fan Cylinder amp Deck Access Doors E A REPLACEMENT PARTS REQUIRED QUAN DESCRIPTION ORDER FROM DATE REQ D MAINTENANCE WORK REQUIRED DESCRIPTION REQ D COMPLETION Personnel safety item inspect semi annually repair as required for safe use Use back of this sheet for additional requirements or notes CS 2066B atte SERVICE THE MARLEY COOLING
20. terials Chlorine and chlorine containing com pounds are effective algaecides and slimicides but excess chlorine can damage wood and other organic materials of construction 1f used chlorine should be added as intermit tent or shock treatment only as frequently as needed to control the slime and algae and free residual levels should not exceed one part per million parts water 1 ppm Chlor ine or chlorine containing compounds should be added carefully since very high levels of chlorine may occur at or near the point of entry into the circulating water system FOAMING Heavy foaming sometimes occurs when a new tower is put into operation This type of foaming generally subsides after a relatively short period of operation Persis tent foaming can be caused by the concentrations of certain combinations of dissolved solids or by contamination of the circulating water with foam causing compounds This type of foaming can sometimes be minimized by increasing the blowdown but in some cases foam depressant chemicals must be added to the system Foam depressants are avail able from a number of chemical companies WATER DISCOLORATION Woods contain some water soluble substances and these commonly discolor the circu lating water on a new tower This discoloration is not harm ful to any of the components in the system and can be ig nored However a combination of foaming and discolored water can result in staining of adjacent structures if foa
21. the side of the Geareducer case Check oil lines to be sure there are no leaks and all joints are tight See Geareducer Service Manual for oil filling procedure and list of recommended lubricants Rotate fan by hand to be sure of free rotation and ample tip clearance See Fan Service Manual Check motor insulation with a Megger See Mainte nance section of Marley Service Manual on Electric Motors Lubricate the motor according to motor manufactur er s instructions Test run each fan separately for a short time Check for excessive vibration or unusual noise If either is present see Tower Trouble Tips on pages 8 and 9 of this manual Fan must rotate clockwise when viewed from above Recheck Geareducer oil level Check functioning of make up water supply Make sure the blowdown or bleed off will carry the proper amount of water 10 11 STARTING PROCEDURE FILLING THE WATER SYSTEM Fill the cold water basin and circulating water system until the operating water level is reached see Operation section page 4 Completely open all hot water flow control valves then prime and start the circulating water pumps Increase the flow of circulating water gradually to design water rate to avoid surges of water hammer which could damage the dis tribution piping Adjust valves to equalize the hot water depth in the distribution basins Lock valves in desired open position with valve locking bar On towers equipped with redwood stav
22. ture is 32 degrees or below do not put cold water on tower MECHANICAL EQUIPMENT Flow Control Valve Grease valve threads at zerk fitting using rust inhibiting lithium base grease of NLGI No 2 consistency and then open valve Coat exposed valve stem with grease Geareducers 3 Months or Less Shutdown 1 Each month drain water condensate from the lowest point of the Geareducer and its oil system Check oil level and add oil if necessary Operate to re coat all interior surfaces with oil 2 At start up drain wat r condensate and check oil level Add oil if necessary Refer to Geareducer service manual for maintenance and lubrication instructions 3 Months or More Shutdown If motors have space heaters operate mechanical equip ment one hour each month If motors do not have space heaters operate mechanical equipment one hour each week At start up operate mechanical equipment one hour or until oil is warm then shut the equipment down Drain the oil and refill with new oil Refer to Geareducer Manual for instructions on changing oil Electric Motors Do not start motor without determining that there will be no interference with free rotation of the fan drive Refer to motor manufacturer s recommendations for lubri cation and maintenance instructions If shutdown period is longer than seasonal contact your Marley sales office or representative for additional informa tion TROUBLE Motor Wit Not Start Unusua M
23. y into the cold water basin is used all water must be by passed Design of a by pass arrangement must include consideration of water impact effect on tower components CAUTION Severely Cold Weather Below 20 F Ambient Dry Bulb Reverse operation of fans for prolonged periods during sub freezing weather can cause severe damage to fans and fan cylinders Ice can accumulate inside fan cylinders at fan blade plane of rotation and fan blade tips will event ually strike this ring of ice damaging the fan blades or cylin der Ice can also accumulate on fan blades and be thrown off damaging fan cylinder or blades Reverse operation of fans with adjacent fans not operating increases probability of icing The low discharge velocity of moist air from fan cylinders in which fans are not in operation can result in moisture ladened air being pulled into the adjacent cylinder in which the fan is operating in reverse increasing this ice build up Therefore fans each side of the one operating in reverse must be operated in forward rotation at full or half speed or all fans must be operated in reverse Allow a mini mum of 10 minute delay between reverse operation and for ward operation during sub freezing weather to permit ice to dissipate from fan blades and fan cylinders See Fan Drive for fan speed change and reversing pre cautions TABLE I INSPECTION amp MAINTENANCE SCHEDULE General Recommendations More frequent inspection and
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