BAC HXV, Operation & Maintenance Manual

Page 1: ...OPERATION MAINTENANCE MANUAL HXV Hybrid Cooler ...

Page 2: ...nt Check motor voltage and current Check motor davit arm is locked in place and away from air stream 4 Clean fan motor exterior Check fan motor for proper rotation Check general condition of the fan Check fan for uniform pitch Check fan for rotation without obstruction Check and recoat steel shafts with RUST VETO Test vibration cutout switch DANGER Rotating equipment will cause severe personal inj...

Page 3: ...22 Water Treatment 23 Corrosion and Scale Control 24 Chemical Treatment Requirements 24 Passivation 24 Biological Control 25 Long Term Care of Stainless Steel 26 System Cleaning PART 4 Bleed Rate 27 Bleed Rate PART 5 Cold Weather Operation 29 Inspection and Maintenance 29 Fan Section Icing Protection 30 Basin Water and Internal Piping Freeze Protection 31 Coil Freeze Protection PART 6 Operation Co...

Page 4: ...procedures Adequate safeguards including the use of protective enclosures where necessary should be taken with this equipment both to safeguard the public from injury and to prevent damage to the equipment its associated system and the premises WARNING A lockable disconnect switch should be located within sight of the unit for each fan motor associated with this equipment Before performing any typ...

Page 5: ...tes from the equipment dissolved solids are left behind which were originally contained in the make up water These dissolved solids may be either alkaline or acidic and as they are concentrated in the circulating water they can cause scaling or accelerated corrosion The extent of impurities in the air and water determines the frequency of most maintenance services and also governs the extent of wa...

Page 6: ... Fluid In Coil Connection Prime Surface Coil Wet Coil Fluid Out Coil Connection Cold Water Basin External Ladder and Safety Cage Option External Platform Option Internal Access Ladder and Platform Air Inlet Louvers Location of Water Level Float Switches Basin Water Level Control and Basin Heater Finned Coil Dry Coil Connections Figure 1 HXV Hybrid Cooler ...

Page 7: ...atent heat transfer which saturates the air before it enters the plenum and flows into the fans The saturated discharge air from the fans passes over the finned coil dry coil to cool the process fluid sensible heat transfer This mode take full advantage of evaporative cooling and therefore reduces the fan energy necessary for cooling Water Saver Mode Dry Mode The process fluid flows through the fi...

Page 8: ...ter Saver Mode Spray pump OFF Fan motors ON with VFD fan motors ramp up and down together 3 way valve fully closed to allow full flow through evaporative coil to maximize dry performance NOTE LWT Fluid Cooler Leaving Water Temperature Sequence of Operation The following is applicable to all sequences of operation All fan speed control operation is based on leaving fluid temperatures Basin heaters ...

Page 9: ...e hail guards Conduct internal inspection of the equipment Check for anything unusual such as structural or mechanical component looseness or damage Inspect piping and connections to verify they are secure Inspect the visible coil surfaces Any corrosion damage or obstructions should be corrected At seasonal start up or after prolonged shutdown check the motor insulation with an insulation tester p...

Page 10: ...er treatment program including biocidal treatment as recommended by the water treatment supplier Check that the float operated make up valve is operating freely Closely monitor water level and adjust as necessary during the first 24 hours of operation Refer to Table 2 for more details Inspect the heat transfer section as described on page 18 and inspect the water distribution system as described o...

Page 11: ...tive finish on the unit Clean and refinish as required Refer to Corrosion Protection on page 22 for more details Lockout the fan motor starting device in the OFF position to ensure personal safety in case of future inspection or service Prolonged Outdoor Storage Conduct the Extended Shutdown procedure above if the unit is installed Ensure the cold water basin is fully drained and the drain is open...

Page 12: ... not use plastic plastic film This cover should extend below the motor and be secured however it should not tightly wrap the motor This will allow the captive air space to breathe minimizing formation of condensation Care must also be taken to protect the motor from flooding or from harmful chemical vapors The storage area should be free from ambient vibration Excessive vibration can cause bearing...

Page 13: ...ves belts or fan blades Start Up Preparation After Prolonged Storage Start up procedures after long periods of storage are just as important as pre shutdown procedures Fan and pump motors should be thoroughly inspected and cleaned to restore them to pre storage condition Inspect axial fan s prior to start up to ensure that the blades are tight and that there is no corrosion or damage Do not energi...

Page 14: ...float when necessary to maintain the recommended operating level Consult Water Level Control on page 19 for information on how to set and maintain basin operating level Inspection Maintenance At least quarterly inspect the cold water basin and remove any trash or debris accumulated in basin or on the strainer If sediment has accumulated in the cold water basin drain clean and flush the cold water ...

Page 15: ...of Rotation On initial start up or if the fan motor has been rewired briefly energize the fan motor and note the direction of rotation It should rotate in the direction indicated by the arrow on the fan cowl On units with independent fan motors check the rotation of each fan Operation On initial start up run the fan in the manual position for several minutes and check for any unusual noises or vib...

Page 16: ...dic check of the belt condition and when necessary tension adjustment The recommended service intervals are as follows Initial Start up Servicing is not required prior to initial unit start up The drive has been tensioned and aligned at the factory Seasonal Start up Readjust the belt tension if required Operation After the first 24 hours of operation readjust the belt tension on a new unit start u...

Page 17: ...kwise to relieve belt tension During adjustment of belt tension rotate the drives several times by hand to evenly distribute the tension throughout the belt When the belt is properly tensioned retighten the locking nut on the motor base adjusting screw Drive alignment check and adjustment Check the drive alignment annually to ensure maximum belt life Place a straight edge across the driver and the...

Page 18: ... the davit Attach a suitable lifting device of sufficient load capacity to the eye hook on the davit arm Attach the other end of the lifting device to the factory supplied lifting points which are mounted on the motor Verify that the lifting device is secure at all attachment points Position the lifting device to take up any slack and to support the weight of the motor with minimal movement when t...

Page 19: ...e exposed motor shaft and bushing Install the drive belt and tension it per the instructions on page 15 Rewire the motor Verify that area is clear of tools and personnel From a safe location re energize the motor and check for proper rotation per the start up instructions Fan Shaft Bearings Two pillow block ball bearings support each fan shaft Each bearing is equipped with a lubrication fitting an...

Page 20: ...l guards Remove any minor fouling chemically Contact your local water treatment consultant for advice CIS Hail guards must be removed before cleaning to avoid contaminating the dry finned coil surfaces Extensive fouling may require mechanical cleaning and flushing Exercise care when cleaning to avoid damage to the PVC components Hail guards must be removed before cleaning to avoid contaminating th...

Page 21: ...ke up assembly consists of a corrosion resistant make up valve connected to a float arm assembly actuated by a polystyrene filled plastic float The float is mounted on an all thread rod held in place by wing nuts The cold water basin operating water level can be adjusted by repositioning the float and all thread rod using the wing nuts provided Inspect the make up valve assembly monthly and adjust...

Page 22: ...Universal Electric Water Level Control Installation Operation Maintenance Manual For Part number 313555 available at BaltimoreAircoil com Clean the stainless steel electrodes periodically to prevent accumulations of scale corrosion sludge or biological growth which could interfere with the electrical circuit The water level is maintained at the recommended operating level regardless of the system ...

Page 23: ...WWW BALTIMOREAIRCOIL COM 21 WWW BALTIMOREAIRCOIL COM 21 ...

Page 24: ... flows through the unit As the water evaporates the dissolved solids originally present in the water remain behind and if not controlled the concentration of dissolved solids will increase rapidly This can lead to corrosion scale or biological fouling which may negatively affect heat transfer as well as the longevity of system components Corrosion Red rust on steel components and white rust on gal...

Page 25: ...water to a drain is used to control the concentration of dissolved solids On rare occasions this may be adequate to control scale and corrosion More often chemical scale and corrosion inhibitors are necessary which can raise the allowable level of dissolved solids without the risk of scale and corrosion Keep the chemically treated water within the guidelines given in Table 3 In cases where bleed b...

Page 26: ...p or until new zinc surfaces turn dull gray in color If white rust forms on galvanized steel surfaces after the pH is returned to normal service levels it may be necessary to repeat the passivation process In case the pH can t be kept below 8 2 a secondary approach is to conduct a chemical passivation using inorganic phosphate or film forming passivation agents Consult your water treatment special...

Page 27: ...n the corrosion resistance as well as to maintain the overall aesthetics of the stainless steel It is fairly simple to clean most contaminants off the surface of stainless steel Most dirt and soil can be cleaned with a clean cloth warm water and mild detergent For persistent dirt a little vinegar can be added in the cleaning water It is important to always rinse the surface with warm water and wip...

Page 28: ...tion should not exceed any of the following 5 Sodium Hydroxide 5 Sodium Metasilicate 2 Sodium Carbonate 2 Tetra Sodium Pyrophosphate 0 5 Trisodium Phosphate 0 5 Sodium Nitrate 5 10 Butyl Cellosolve Coil Cleaning for HXV Hybrid Coolers The outside of the coils may require occasional cleaning The chemicals used must be compatible with the materials being cleaned For example the prime surface coil is...

Page 29: ...ecirculating water to the concentration of the same material in the make up water In order to optimize heat transfer efficiency and maximize equipment life bleed or blowdown a small amount of recirculating water from the system This controls the cycles of concentration to maintain the quality of the recirculating water within the guidelines given in Table 3 on page 23 Replenish the bleed water wit...

Page 30: ...ow Rate USGPM R Range n Number of Cycles of Concentration CR CM CR Concentration in Recirculating Water CM Concentration in Make up Water Given Closed Circuit Cooling Tower Process Fluid Flow Rate 800 USGPM Maximum Allowable Chloride Concentration 250 ppm Concentration of Chlorides in Make up Water 45 ppm Range 10 F Find Bleed Rate Solution So in this case E Q R 0 001 800 10 0 001 8 USGPM n CR 250...

Page 31: ...ting fan control and dry operation The method of control employed on a given application depends upon the climatic extremes which are expected the variations in heat load that will be encountered and the compatibility of the control system with other portions of the installation In subfreezing ambient temperatures effective icing control may require a combination of these three methods Operate eac...

Page 32: ...the fan blades for ice formation Dry Operation The HXV Hybrid Cooler provides high switch points for dry operation One method to prevent icing is dry operation Dry operation of the HXV unit protects fans from ice formation due to mist and splash from the cold water basin The water in the cold water basin must be drained for dry operation in freezing ambient conditions For dry operation switch poin...

Page 33: ...light or shut off apply an auxiliary heat load to the circulating fluid and adjust the flow to ensure that fluid leaving the prime surface coil wet coil maintains the minimum required temperature Emergency Coil Drain Do not drain the coils as a normal method of freeze protection Frequent draining promotes corrosion inside the coil tubes However draining is acceptable as an emergency method of free...

Page 34: ...upport Stand Alone BAC Heater Control Panel Optional The heater control system consists of a heater control panel and a combination temperature water level sensor The stainless steel sensor probe with 1 2 NPT mounting fitting has an on off relay output that de energizes the heaters whenever the basin water temperature is above 45 F 7 2 C or whenever the sensor probe is not fully submersed The cont...

Page 35: ...d tag out the circuit Remove the resistor and place it back in the storage bag Check all connections reconnect sensor wires per the wiring diagram to terminals T1 and T2 replace the cover and place the system back in service lades for ice formation Operation when the sensor probe is encased in ice Disconnect the heater control panel and tag out the circuit Remove the heater control panel cover Ins...

Page 36: ... the VCOS housing cover to protect the inside of the switch housing from moisture ingress Ensure the cover gasket is intact If desired the VCOS can be periodically calibrated as follows De energize lock out and tag out power to the fan motors before entering the HXV unit to reset test or calibrate the VCOS Carefully remove the cover from the VCOS housing Mount an accelerometer connected to a vibra...

Page 37: ...al Vibration Cutout Switch Standard Set Point Adjustment When Installed 1 For safety turn off then lock and tag out the electrical supply to the fan motor s 2 Turn adjustment screw counterclockwise 1 8 turn at a time until you hear the control trip 3 Once tripped rotate adjustment screw turn clockwise Push in the manual reset button 4 Start up the fan s to determine if the start up will cause the ...

Page 38: ...ions utilizing variable frequency drives VFDs for fan motor control must use inverter duty motors built in compliance with NEMA standard MG 1 Part 31 Operation of the unit at a speed which resonates with components of the drive system or support structure may result in vibrations which could damage the components or structure and or create objectionable noise Therefore these resonant speed ranges ...

Page 39: ... and ensure that the drive system is all clear Remove the lockout from the motor circuit With the VFD off record the vibration level indicated on the vibration analyzer and confirm that it is very low only picking up ambient vibration Record this overall vibration level 0 peak in inches per second ips If the ambient vibration level is greater than 0 35 ips identify and correct the cause of the vib...

Page 40: ...s 0 35 ips as the upper end of the lockout range Using this data a baseline for vibration history can be developed The vibration levels can be monitored yearly and the trend used to indicate potential wear or the need to replace components in the drive system After the entire speed range has been checked and any resonances identified ensure the VFD that controls the fan motor is then turned off an...

Page 41: ...e hole from the outside of the cold water basin a Use a hole saw or a step drill bit for smaller connections 3 or less as shown in Figure 13 b Use a reciprocating saw or a Sawzall for larger connections 3 or greater 5 Position the BAC supplied stainless steel backing ring gasket to the inside of the cold water basin 6 Position the flange to the outside of the cold water basin 7 Bolt the flange and...

Page 42: ...ING TOWERS ICE THERMAL STORAGE EVAPORATIVE CONDENSERS HYBRID PRODUCTS PARTS SERVICES w w w B a l t i m o r e A i r c o i l c o m 7600 Dorsey Run Road Jessup MD 20794 Telephone 410 799 6200 2022 Baltimore Aircoil Company RGOMHXV 01_R2 0 ...