Sigma™ – Series 10 / 15 cooling tower
Contents
1. xX A T San 45 Q0 LN a 45 aB Y in N W lt zZ W z lt zZ 2 lt W Q e z 2 lt l l lt 0 z READ AND UNDERSTAND THIS MANUAL PRIOR TO OPERATING OR SERVICING THIS PRODUCT Z0238867 rev A ISSUED 05 2015 Sigma F Series 7 Marley Note Warning A Caution Note contents This manual contains vital information forthe proper installation and operation of your cooling tower Carefully read the manual before installation or operation of the tower and follow all instructions Save this manual for future reference 10224 tgaPitesfazeg aly 2 Towe rotan p esnean a a 3 Tower OPO ration sariini riiai nai 6 Wintertime Ope 51111 nonen tbnsa 8 Water Treatment and 3 9 010 1 10 Schedule of Tower Maintenance 12 Seasonal Shutdown INStructions 14 Prolonged SHUTAOWN 15 Matley SerViGeS 16 1 171 11 1016791 1716 55 1 18 The following defi2. 4 under Tower Operation However in towers of more than one cell the limiting temperature established applies to the water temperature of the cell or cells operating at the highest fan speed not necessarily the net cold water temperature produced by the entire tower As coldair enters the louvers it causes the falling water to be drawn inward toward the center of the tower Thus under fan operation the louvers and lower periphery ofthe tower structure remain partly dry seeing only random splashing from within the tower plus normal atmospheric moisture from the entering air Such lightly wetted areas are most subject to freezing Therefore if excessive ice forms on the louvers stop the fan for a few minutes With the fan off the water flow will increase in the vicinity of the louvers and reduce the ice buildup 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 accumulated ice adequate heat load must be available Fan reversal at half speed is recommended Reverse operation of the fan should be used sparingly and should only be used to control ice not to prevent it Reverse fan operation should not need to exceed 1 or 2 minutes Monitor ing is required to determine the time required to melt accumulated ice Reverse operation of fans for prolonged periods during subfreezing weather can cause severe damage to fans and fan cylinde
3. Cor Incorrect fan blade pitch rect if necessary See Fan Service Manual Geareducer bearings If new see if noise disappears after one week of operation Drain flush and refill Geareducer See Geareducer Service Manual If still Geareducer noise Gears noisy replace bearings Correct tooth engagement Replace badly worn gears Replace gears with imperfect tooth spacing or form Improper water treatment or See Water Treatment section of this manual Contact your Marley sales representative Wood deterioration microbiological attack 19 SPX COOLING TECHNOLOGIES INC 7401 W 129 STREET OVERLAND PARK KANSAS 66213 USA P 913 664 7400 F 913 664 7439 spxcooling spx com In the interest of technological progress all products are subject to design and or material change without notice ISSUED 05 2015 Z0238867 rev A M92 1319G COPYRIGHT 2015 SPX Corporation Sigma Series 10 15 user manual
4. external drain plug near the motor Check oil level and add oil if neces sary Operate Geareducer to re coat all interior surfaces with oil Check Geareducer anchor bolts and tighten as required 3 At next season startup operate Geareducer until oil is warm change oil Fans Check fan assembly bolting and tighten as required Use torque set tings prescribed on the fan nameplate Electric motors Clean and lubricate motor at close of each operating sea son Refer to motor manufacturer s recommendations Check motor anchor bolts and tighten as required Do not start motor before determining that there will be no interfer ence with free rotation of the fan drive The motor should be operated for three hours at least once a month This serves to dry out windings and re lubricate bearing surfaces Refer to Marley electric motor service manual At the start of a new operating season make sure bearings are adequately lubricated before returning motor to service Flow Control Valves Apply a marine type lithium base grease at the grease fitting of each valve and then open valve Coat exposed valve stem with grease Fiberglass Components Check all fiberglass parts for exposed glass fibers If found the affected surfaces should be roughened up and solvent wiped Surfaces must be clean and dry and free of oil grease or other contaminants before applying new coating The best coating system requires using a two part polyam
5. season The periodic flushing and cleaning should be done before and after each cooling season but in any event at least twice a year The hot water basins and nozzles louvers drift eliminators and easily accessible fill surfaces should be flushed by use of a moderate pressure water nozzle being careful not to cause physical damage A reliable water treatment program should be installed and maintained Filtration devices may be employed to reduce the suspended solids concentrations thus increasing the effectiveness of the water treatment program Blowdown Acooling tower cools water by continuously causing a portion of it to evaporate Although the water lost by evaporation is replenished by the makeup system it exits the tower as pure water leaving behind its burden of dissolved solids to concentrate in the remaining water Given no means of control this increasing concentration of contaminants can reach a very high level 11 Note A Warning 12 maintenance Blowdown Rate Cooling Two Four Range F Concentrations Concentrations 10 0 7 0 17 15 1 1 0 30 20 1 5 0 43 Range Difference between hot water temperature entering the tower amp cold water temperature leaving the tower In order to achieve water quality which is acceptable to the cooling tower as well as the remainder of your circulating water system the selected water treat ment company must work from a relatively consta
6. to prevent damage to tower components Air flow rate Reducing air flow through the tower causes the cold water temperature to rise This is the approved method by which to control leaving water temperature If your tower is equipped with a single speed motor the motor may be shut off when the water temperature becomes too cold This will cause the water temperature to rise When the water temperature then becomes too warm for your process the motor can be restarted Note Note operation Fan cycling limits On 20 foot diameter fans and smaller anticipate that approximately 4 to 5 starts per hour are allowable On larger fans 1 or 2 starts per hour may be the limit If your tower is equipped with a two speed motor you will have greater opportunity for temperature control When the water temperature be comes too cold switching the fan to half speed will cause the cold water temperature to rise stabilizing at a temperature some 5 to 15 higher depending upon a combination of all operating factors With a further reduction in water temperature the fan may be cycled alternately from half speed to off Do not start the motor more than four to five times per hour each low speed start and each high speed start count as one start If your tower consists of two or more cells cycling of motors may be shared between cells increasing your steps of operation accordingly For greater insight on cold water temperatur
7. ases of emergency they can normally be shipped within 24 hours by air freight if necessary However we would recommend that you anticipate their need in advance and avoid the cost of special handling Be sure to mention your tower serial number from the tower nameplate when ordering parts Periodic maintenance You may wish to contract with SPX Cooling for regularly scheduled visits for the purpose of inspecting and reporting your tower s condition to make recommendations intended to prevent emergen cies and to perform maintenance considered outside the norm This service is not intended to replace the important function performed by your maintenance staff Their attention assures the tower s routine operating performance and is invaluable However we recognizes that the unusual manner in which a cooling tower performs its function as well as the unique forces which act upon it may be considerations which occasionally require the services of an expert technician additional Information Increased load requirements Marley towers are designed so that cells of either equal or unequal capacity can be added in the future This allows you to compensate for the load increases that normally occur with the replacement or addition of production equipment and still retain continuity with respect to your cooling tower system Tower rebuilding Marley routinely rebuilds and upgrades cooling towers of all materials and makes If your t
8. e against power supply Check voltage at motor terminals Open circuit in motor winding Check stator windings for open circuits Motor or fan drive stuck Disconnect motor from load and check motor and Geareducer for cause of problem Rotor defective Look for broken bars and rings Unusual motor noise Motor running single phase Stop motor and attempt to start it Motor will not start if single phased Check wiring controls and motor Motor leads connected incorrectly Check motor connections against wiring diagram on motor Bad bearings Check lubrication Replace bad bearings Electrical unbalance Check voltage and currents of all three lines Correct if required Air gap not uniform Check and correct bracket fits or bearing Rotor unbalance Rebalance Cooling fan hitting end bell guard Reinstall or replace fan Fan noise Scale or foreign substance in water system Motor does not come up to speed Blade rubbing inside of fan cylinder Adjust cylinder to provide blade tip clearance Loose bolts in blade clamps Lack of or insufficient bleed off Check and tighten if necessary Check fan blade pitch Refer to Fan Service Manual See Water Treatment section of this manual Water treatment Voltage too low at motor terminals because of line drop Consult competent water treating specialist See Water Treatment section of this manua
9. e control please read Techni cal Report H 001 A Cooling Tower Energy and its Management available from your Marley sales representative Wintertime Operation During operation in subfreezing weather the opportunity exists for ice to form in the colder regions of the tower Your primary concern is to prevent the formation of destructive ice on the cooling tower fill Your understand ing of cold weather operation will be enhanced if you read Technical Report H 003 Operating Cooling Towers in Freezing Weather augmented by the following guidelines 1 Do not allow the tower s leaving water temperature to drop below a mini mum allowable level about 40 F established as follows During the coldest days of the first winter of operation observe whether any ice is forming on the louver face particularly near the bottom of the louver face If hard ice is present on the louvers an appropriate elevation in the allowable cold water temperature is mandatory If the coldest possible water is beneficial to your process ice of a mushy consistency can be tolerated but routine periodic observation is advisable If the minimum allowable cold water temperature is established at or near minimum heat load it should be safe for all operating conditions A Warning operation Having established the minimum allowable cold water temperature maintain ing that temperature can be accomplished by fan manipulation as outlined in Item
10. ections and tighten as required Make preventive maintenance repairs as considered necessary Every 5 Years Geareducer models 10 1 1800 2000 2200 and 2400 only Change Geareducer oil Refer to Geareducer Manual for instructions Spare Parts If your tower application is critical you should consider maintaining a stock of replacement mechanical equipment components We recommend these parts for your spare parts inventory 1 One fan assembly 2 One Geareducer assembly 3 One drive shaft assembly Be sure to include the tower model number and serial number when you order parts Seasonal Shutdown Instructions When the system is to be shut down for an extended period of time it is recommended that the entire system cooling tower system piping heat exchangers etc be drained Leave the basin drain open During shutdown clean the tower and make any necessary repairs Pay par ticular attention to mechanical equipment supports and drive shafts Protect wood towers against fire If you choose to wet down your tower for fire protection use a continuous wet down system Alternate wetting and drying can severely damage lumber Tower framework Check structural bolted connections and tighten as required A Caution maintenance Geareducers except 10 1 1800 2000 2200 and 2400 1 Each month during shutdown drain any water that may have condensed inside the Geareducer and lubrication system This can be done at the
11. ide epoxy primer to promote adhesion and a two part acrylic poly urethane enamel for the topcoat Contact your Marley sales representative if additional information is required Prolonged Shutdown If shutdown period is longer than seasonal contact your Marley sales repre sentative for additional information 16 additional Information SPX Cooling Technologies Services Our interest in your cooling tower does not end with the sale Having con ceived designed and manufactured the most reliable and longest lasting cooling tower of its class we want to make sure that you gain the maximum possible benefit from its purchase Therefore the following services are available which are intended to assure the maximum possible service life under your operating conditions tailor the operating characteristics to your specific needs and maintain consistently optimum thermal performance capability They are available by contacting your Marley sales representative Replacement parts With the exception of the motor every component of your tower is designed and manufactured by SPX Cooling Technologies We do this because commercially available components have not proved capable of withstanding the harsh environment of a cooling tower nor do they contribute their share to the thermal capability and operating characteristics intended A stock of most parts and components is maintained at one or more of the various Marley plants In c
12. in Geareducer and refill with fresh oil as outlined in the Geareducer Manual If sludge is present in the oil flush Geareducer before refilling Oil changes have been reduced to 5 year intervals for Geareducer models 10 1 1800 2000 2200 and 2400 To maintain five year change intervals use only oil designed specifically for these Geareducers If after five years turbine type mineral oil is used the oil must be changed semi annually Refer to Geareducer Manual for oil recom mendations and further instructions Relubricate motor according to the manufacturer s instructions Check to see that all bolts are tight in the fan and mechanical equipment region including the fan cylinder Use torque settings prescribed in the Fan Manual Remove any accumulated debris dirt or algae from the hot water basins andthe distribution nozzles Make sure that all nozzle metering orifices are in place Visually inspect the drift eliminators Remove any accumulated debris or scale 14 maintenance Clean and disinfect cooling tower with biocides Systems with biofouling high general bacterial counts or positive cultures of legionella may require additional cleaning Refer to Cooling Tower Cleaning section Consult your water treatment expert as to prudent biological evalutaion testing Annually Inspect the tower thoroughly making maximum use of instructions given in the separate service manuals Check structural bolted conn
13. in its proper hub socket 3 Momentarily energize bump the motor and observe rotation of the fan The fan should rotate in a counterclockwise direction when viewed from below If rotation is backwards shut off the fan and reverse two of the three primary leads supplying power to the motor If tower is equipped with a two speed motor check for proper rota tion at both speeds Check also to see that starter is equipped with a 20 second time delay which prevents direct switching from high speed to low speed This delay will allow the fan to slow down and will prevent abnormal stress from being applied to the mechanical equipment and the electrical circuit components 4 Run the motor and observe the operation of the mechanical equipment Operation should be stable and there should be no evidence of oil leakage In general you should allow several days of operation before evaluating vibration A wood structure must be thoroughly wet in order to provide proper mechanical dampening If the water supply system is not being operated or if there is no heat load on the system motor amps read at this time may indicate an apparent overload of as much as 10 20 This is because of the increased density of unheated air flowing through the fan Deter mination of an accurate motor load should await the application of the design heat load operation Tower Operation General The cold water temperature obtained from an operating coo
14. ity for any such deviation change or modification The equipment shall be warranted in accordance with the applicable SPX Cooling Technologies Certification of Limited Warranty If you have questions about the operation and or maintenance of this cooling tower and you don t find the answers in this manual please contact your Marley sales representative When writing for information or when ordering parts please include the serial number shown on the cooling tower nameplate The cooling tower must be located at such distance and direction to avoid the possibility of contaminated tower discharge air being drawn into building fresh air intake ducts The purchaser should ob tain the services of a Licensed Professional Engineer or Registered Architect to certify that the location of the tower is in compliance with applicable air pollution fire and clean air codes Tower Startup Among other sources outbreaks of Legionnaires Disease have reportedly been traced to cooling towers Maintenance and water treatment 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 When you first start up your tower or when you start up after a prolonged shutdown you should thoroughly clean and inspect the tower The following checklist will help to guide you through this pr
15. l Check transformer and setting of taps Use higher voltage on transformer terminals or reduce loads Increase wire size or reduce inertia Broken rotor bars Look for cracks near the rings A new rotor may be required Have motor service center check motor Wrong rotation Motor Excessive water drift Cold water too warm See Tower Operation Wrong sequence of phases Faulty drift elimination Overpumping Overpumping Switch any two of the three motor leads 1 See if all louvers and eliminators are in place and clean 2 Check to see that nozzles are in place and clean of debris Reduce water flow rate to tower to design conditions Reduce water flow rate to tower to design conditions Not enough air Check motor current and voltage to be sure of correct contract horsepower Clean louvers fill and eliminators 18 troubleshooting Trouble Cause Remedy Unusual fan drive vibration Loose bolts and cap screw Tighten all bolts and cap screws on all mechanical equipment and supports Worn coupling or misalignment Make sure motor and Geareducer shafts are in proper alignment and match marks properly matched Repair or replace worn couplings Unbalanced fan Be sure blades are properly positioned in correct sockets See match numbers Make certain all blades are as far from center of hub as safety devices permit All blades must be pitched the same See Fan Service Man
16. ling tower will vary with the following influences 1 Heat load With the fan in full operation if the heat load increases the cold water temperature will rise If the heat load reduces the cold water temperature will reduce The number of degrees range through which the tower cools the water is established by the system heat load and the amount of water being circulated in accordance with the following formula Heat Load Btu hr Range F a CF GPM x 500 The cooling tower establishes only the cold water temperature attainable under any operating circumstance Air wet bulb temperature Cold water temperature will also vary with the wet bulb temperature of the air entering the louvered faces of the tower Reduced wet bulb temperatures will result in colder water temperatures However the cold water temperature will not vary to the same extent as the wet bulb For example a 20 F reduction in wet bulb may result in only a 15 F reduction in cold water temperature Water flow rate Increasing the water flow rate GPM will cause an elevation in cold water temperature while reducing the water flow rate will cause the cold water temperature to lower However at a given heat load see formula above GPM reductions also cause an increase in the incoming hot water temperature Unless your tower was specifically designed for higher hot water inlet temperatures use care to prevent the hot water from exceeding 1 20 F
17. ll will allow you to operate at lower water levels without allowing air to bypass below the tower fill Your Marley sales representative will gladly help you to meet this need Preweiting your wood collection basin for several days will cause the lumber to swell eliminating most basin leaks If leaks exist after several days apply a polyurethane sealer to the leaking joints You can eliminate most leaks in steel basins by tightening the bolted joints and sealing with polyurethane sealer 4 Completely open all hot water flow control valves Start your pump s Observe system operation Since the water system external to the tower will have been filled only to the level achieved in the cold water basin a certain amount of pump down of the basin water level will occur before water completes the circuit and begins to fall from the fill The amount of initial pump down may be insufficient to cause the float valve to open However you can check its operation by pressing down on the operating lever to which the stem of the float valve is attached While operating the condensing water pump s and prior to operating the cooling tower fan execute one of the two alternative biocidal treatment programs described in the following Resume treatment with the biocide which had been used prior to shut down Utilize the services of the water treatment supplier Maintain the maximum recommended biocide residual for the specific biocide for a
18. ma F Series towers are self balancing and do not require valve Tower Model Distribution Basin Depth Series 10 2 4 Series 15 38 5 12 Sigma Steel 3 5 yo Sigma Wood 3 8 Sigma F Series 3 8 adjustment from one side of cell to the other Adjust valves in supply piping to balance flow from cell to cell on multicell tower installations Uniform distribution basin depth is essential for efficient tower operation Contact your Marley sales representative if you are considering a change in circulating water flow rate that would prevent operation within these limits Warning Caution Note operation Mechanical Equipment Always make certain that mechanical equipmentis inoperable during periods of maintenance or during any situation of possible endan germent to personnel If your electrical system contains a discon nect switch lock it out until the period of exposure to injury is over 1 Check the Geareducer oil level at the sight glass or dip stick near the motor If oil is required fill to the proper level 2 Spin the fan manually to assure that all fan blades properly clear the inside of the fan cylinder Observe the action of the drive shaft couplings to be sure that the motor and Geareducer are properly aligned If necessary correct the alignment in accordance with the included drive shaft manual Ensure that fan blades are pitched uniformly and that each blade is installed
19. ned terms are used throughout this manual to bring attention to the presence of hazards of various risk levels or to important information concerning the life of the product Indicates presence of a hazard which can cause severe personal injury death or substantial property damage if ignored Indicates presence of a hazard which will or can cause personal injury or property damage if ignored Indicates special instructions on installation operation or main tenance which are important but not related to personal injury hazards Overview This User Manual as well as those offered separately on motors fans Geareducer couplings drive shafts float valves pumps etc are intended to assure that this cooling tower serves you properly for the maximum possible time Since product warrantability may well depend upon your actions please read this User Manual thoroughly prior to operation This User Manual provides information regarding general cooling tower in stallation and operation Any deviation from change or modification to the User Manual the original design conditions or the original intended use of the equipment may result in improper installation and or operation of the tower Any such deviation change or modification shall be the responsibility of the party or parties making such deviation change or modification SPX Warning Warning operation Cooling Technologies Inc expressly disclaims all liabil
20. ning of each wintertime shutdown period If tower basin is drained verify that all basin heaters have been shut off either by automatic cutoff or disconnect switch It is recommended that you discuss your freeze prevention options with your local Marley sales representative Water Treatment and Blowdown Maintaining Water Quality The materials used in your tower are selected to offer long corrosion free service in a normal cooling tower environment defined as follows Circulating water with a pH between 6 5 and 9 a chloride content as NaCl below 750 ppm a sulfate content SO below 1200 ppm carbonate or bicarbonates below 300 ppm as CaCO a maximum inlet water temperature not to exceed 120 F 49 C no significant contamination with unusual chemicals or foreign substances and adequate water treatment to minimize scaling Sigma Steel Cooling Tower only Circulating water with a pH between 6 5 and achloride content as NaCl below 500 ppm a sulfate content SO below 250 ppm total alkalinity below 500 ppm calcium hardnes as CaCO above 50 ppm Startup Conditions The water conditions during the initial tower opera tion are crucial in preventing premature corrosion of galvanized steel white rust For at least the first eight weeks of operation pH should be controlled between 6 5 and 8 0 with hardness and alkalinity levels between 100 and 300 ppm expressed as CaCO Chlorine if added intermitten
21. nt level of concentrations This stabilization of contaminant concentrations is usually accomplished by blowdown which is the constant discharge of a portion of the circulating water to waste As a rule acceptable levels on which to base a treatment schedule will be in the range of 2 4 concentrations The table above gives approximate rates of blowdown per cent of total water flow rate constantly wasted to achieve those concentrations at various cooling ranges When water treatment chemicals are added they should not be in troduced into the circulating water system via the cold water basin of the cooling tower Water velocities are lowest at that point which results in inadequate mixing Schedule of Tower Maintenance Included in the instruction packet are separate User Manuals on each major operating component of the tower and it is recommended that you read them thoroughly Where discrepancies may exist the separate User Manuals will take precedence The following is recommended as a minimum routine of scheduled maintenance Always shut off electrical power to the tower fan motor prior to performing any inspections that may involve physical contact with the mechanical or electrical equipment in or on the tower Lock out and tag out any electrical switches to prevent others from turning the power back on Service personnel must wear proper personal protective clothing and equipment Daily Observe touch and listen to the tower fo
22. ocedure Water System 1 Newinstallations should be cleaned and treated with biocides by a water treatment expert before startup 2 Remove any and all accumulated debris from tower Pay particular atten tion to inside areas of cold water basin entire hot water basin and air inlet louvers Make sure that cold water suction screens and sump are clear and properly installed Check to see that nozzles in hot water distri bution basin are properly installed and free of debris Use low pressure water stream as necessary to clean hot and cold water basins and the fill area Note operation For Series 10 and Series 15 cooling towers with wood collection basins fill the water system to an approximate depth of 5 For Sigma cooling towers with wood or steel collection basins fill the water system to a depth of 6 This is the recommended operating water level Adjust the float valve so that it is essentially closed at that level Continue filling the system until the water reaches a level approximately Ye below the lip of the overflow For Series 10 towers with concrete cold water basin the operating water level should be 6 1 below top of basin curb wall For Series 15 towers with concrete cold water basin the operating water level should be 11 below top of basin curb wall For Sigma cooling towers with concrete cold water basin the operating water level should be 1 0 below top of basin curb wall Special air baffles under the fi
23. ower ever reaches the limit of its service life we recommend that you investigate the cost of rebuilding before you routinely order a new replacement tower Marley also provides several sets of a separate packet of pertinent operating and maintenance manuals The manuals vary somewhat depending on the tower model purchased In addition Marley publishes numerous technical reports including more detailed information on a variety of cooling tower operation and service topics Your Marley sales representative will be happy to give you copies of these reports at no charge These publications can also be located at spxcooling com For complete parts and service assistance contact the Marley sales or representative office in your area If you need help locating the of fice nearest you please phone 913 664 7400 or check the internet at spxcooling com 17 troubleshooting Trouble Cause Remedy Motor will not start Power not available at motor terminals 1 Check power at starter Correct any bad connections between the control apparatus and the motor 2 Check starter contacts and control circuit Reset overloads close contacts reset tripped switches or replace failed control switches 3 If power is not on all leads at starter make sure overload and short circuit devices are in proper condition Wrong connections Check motor and control connections against wiring diagrams Low voltage Check nameplate voltag
24. r a few moments each day Become accustomed to its normal appearance sound and level of vibration Abnormal aspects relating to the rotating equipment should be considered rea son to shut down the tower until the problem can be located and corrected Note maintenance Weekly Observe operation of the motor drive shaft Geareducer and fan Become familiar with the normal operating temperature of the motor as well as the sight and sound of all components as a whole Shut off the fan for a few minutes check the level of oil in the Geareducer Add oil as necessary Check system for leaks if the amount of oil required appears unusual If oil is added at the external fill port allow adequate time for the level to stabilize before reading final level Inspect louvers and basin trash screens and remove any debris which may have accumulated Replace any damaged or worn out components Use of high pressure water may damage the eliminator and louver material Check for any buildup of silt on the floor of the cold water basin Mentally note the amount if any so future inspections will enable you to determine the rate at which it is forming Inspect for bacterial growth and general operating conditions Bacterial growth should be reported to your water treatment expert for immediate attention Monthly Check Geareducer oil sample for presence of water and or sludge Make sure vents are open See Geareducer Manual Semi Annually Dra
25. rs Ice can accumulate inside fan cylinders at fan blade plane of rotation and fan blade tips will eventually strike this ring of ice damaging the fan blades or cylinder Ice can also accumulate on fan blades and be thrown off damaging fan cylinder or blades Allow a minimum of 10 minute delay between reverse operation and forward opera tion during subfreezing weather to permit ice to dissipate from fan blades and fan cylinders See Fan Drive Caution note on page 5 for fan speed change and reversing precautions 4 With no heat load on the circulating water icing cannot be controlled effectively by air control during freezing weather Towers must not be operated with reduced water rate and or no heat load during freezing weather If the circulating water system cannot be shut down water returning from the process should be made to bypass the tower If a bypass is used all water must be bypassed without modulation If the water bypass is directly into the tower s cold water basin its design must be approved by Marley Engineering A Caution Warning maintenance Intermittent Wintertime Operation If periods of shutdown nights weekends etc occur during freezing weather measures must be taken to prevent the water in the cold water basin and all exposed pipework from freezing Unless some means of freeze prevention is incorporated into your system the tower basin and exposed pipework should be drained at the begin
26. sufficient period of time residual and time will vary with the biocide to bring the system under good biological control or Note operation Treatthe system with sodium hypochlorite to a level of 4 to 5 mg L ppm free chlorine residual at a pH of 7 0 to 7 6 The chlorine residual must be held at 4 to 5 mg L ppm for six hours measurable with standard commercial water test kits If the cooling tower has been in operation and then shut down for a du ration of time and not drained perform one of the two previous biocidal treatment programs directly to the cooling water storage vessel cooling tower sump drain down tank etc without circulating stagnant water over the cooling tower fill or operating the cooling tower fan After biocidal pretreatment has been successfully completed cooling water may be circulated over the tower fill with the fan off When biocidal treatment has been maintained at a satisfactory level for at least six hours the fan may be turned on and the system returned to service Resume the standard water treatment program including biocidal treatment After reaching design water flow rate adjust the valves to equalize hot water depth in the distribution basins See the following table for hot water basin depths for various models Water basin depth should be uniform basin to basin Lock valves in desired position by tightening the locking bar Coat the exposed valve stem with a marine type grease Sig
27. tly with a free residual not to exceed 1 ppm maintained for short periods Free residual should not exceed 0 4 ppm if chlorine is added continuously Excessive chlorine levels may deteriorate sealants and other materials of construction A Warning maintenance An atmosphere surrounding the tower no worse than moderate indus trial where rainfall and fog are no more than slightly acid and they do not contain significant chlorides or hydrogen sulfide H S Cooling tower cleaning Any evaporative type cooling tower must be thoroughly cleaned on a regular basis to minimize the growth of bacteria including Legionella Pneumophilia to avoid the risk of sickness or death Service personnel must wear proper personal protective equipment during decontamination Do NOT attempt any service unless the fan motor is locked out Operators of evaporative cooling equipment such as water cooling towers should follow maintenance programs which will reduce to an absolute minimum the opportunity for bacteriological contamination Public Health Service officials have recommended that good housekeeping procedures be followed such as regular inspections for concentrations of dirt scale and algae periodic flushing and cleaning and the following of acomplete water treatment program including biocidal treatment See Tower Startup instructions on page 3 The visual inspection should take place at least once a week during the oper ating
28. ual Clean off deposit buildup on blades Check fan and pinion shaft endplay Replace bearings as neces Worn Geareducer bearings sary Disconnect load and operate motor If motor still vibrates rebalance Unbalanced motor rotor Check fan and pinion shafts with dial indicator Replace if neces Bent Geareducer shaft sary Check voltage and current of all three lines against nameplate Motor runs hot Motor overload wrong voltage or unbal anced voltage values Check nameplate against power supply Check RPM of motor and Wrong motor RPM gear ratio Remove grease reliefs Run motor up to speed to purge excessive Bearings overgreased grease Change to proper lubricant See motor manufacturer s instructions Wrong lubricant in bearings Stop motor and attempt to start it Motor will not start if single phased Check wiring controls and motor One phase open Clean motor and check ventilation openings Allow ample ventila tion around motor Poor ventilation Check with Ohmmeter Straighten or replace shaft Winding fault Remove plugs and regrease bearings Bent motor shaft Limit cumulative starting time to a total of 30 seconds each hour Insufficient grease Flush bearings and re lubricate Too frequent starting Deterioration of or foreign material in grease Bearings damaged Replace bearings Measure actual fan pitch and compare to that recommended
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