/ Marley MD Cooling Tower / User Manual 08-1616A
Contents Note This manual contains vital information for the 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. Tower Location..................................................................................................... 4 Tower Shipment.................................................................................................... 4 Hoisting Tower....
Preparation The Marley MD cooling tower purchased for this installation represents the current state of the art in counterflow, induced draft cooling tower design. Thermally and operationally, it is the most efficient cooling tower of its class. These instructions—as well as those offered separately on motors, fans, controls, vibration switches, etc.—are intended to assure that the tower serves you properly for the maximum possible time.
Preparation Several options are available that may assist you in addressing some of these personnel safety concerns, including: — mechanical access platform and ladder — ladder extensions (used where the base of the tower is elevated) — inclined mechanical access ladders — safety cages for ladders — motor located outside the tower Tower Location Space available around the tower should be as generous as possible to promote ease of maintenance—and to permit freedom of airflow into and through the tower.
Receiving and Hoisting Receiving Tower Prior to unloading the tower from the delivering carrier, inspect the shipment for evidence of damage in transit. If damage is apparent, note the freight bill accordingly. This will support your future recovery claim. Find and remove the installation instruction drawings and bills of material located in a plastic container in the cold water basin. This information should be kept for future reference and maintenance purposes.
Installation Tower Installation Note These installation instructions are intended to help you prepare before your tower arrives. If discrepancies exist between these instructions and those shipped with the tower, the instructions shipped with the tower will govern. 1. Prior to placement of the tower, confirm that the supporting platform is level, and that the anchor bolt holes are correctly located in accordance with Marley drawings. 2.
Installation Note If tower purchased is one fan cell only, ignore steps 4 through 8. 5. If collection basins are to be equalized by the use of Marley standard flumes, unbolt the coverplate from the basin of the cell just installed. The coverplate is located in the collection basin depressed section end. 6. Unbolt temporary coverplate from the basin of the second cell and set the bottom module of the second cell in place. Align anchor bolt holes and flume openings in basin sides. 7.
Installation installed in the square opening in the floor of the cold water basin of one or more cells—sealed against leakage, and attached by machine bolts, according to the installation drawing included. An appropriately sized circular opening in the vertical face of the sump has been drilled to 125# ANSI B16.1 flat-face flange specifications. A full faced gasket and appropriately sized bolts (by others) must be used for proper distribution.
Installation Motor Wiring Wire motor leads as shown on the motor nameplate matching the supply voltage. Do not deviate from the motor nameplate wiring. Either of following symbols may be shown on the motor nameplate – Δ, Δ Δ, Y, or YY. These symbols represent how the motor is constructed on the inside and in no way have anything to do with a Delta or Wye electrical distribution system serving the motor. When using a starter: • Set motor overload protection to 110% of motor nameplate amps.
Installation • If cable distance between the VFD and motor is greater than 100 feet a DV/DT output filter is recommended to avoid damage to the motor. 100 feet distance is based on our field experience, the VFD manufacture may state different distances and distance does vary depending on the VFD manufacture. • Program the VFD for variable torque output. Flux vector and constant torque modes may damage the gearbox. • Do not start and stop the motor using the safety switch at the motor.
Installation Mechanical Equipment: Warning Always shut off electrical power to the tower fan motor prior to performing any maintenance on the tower. Any electrical switches should be locked out and tagged out to prevent others from turning the power back on. 1. Spin the fan manually to assure that all fan blades properly clear the inside of the fan cylinder. For belt drive equipped models observe the action of the sheaves and belts to be sure that the motor is properly aligned with the fan sheave.
Installation 3. Run the motor and observe the operation of the mechanical equipment. Operation should be stable. 4. Check belt tension and torque on the fan and motor sheave after 10 to 60 hours of operation. See Bushing Fastener Torque Values on page 25. Note 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%.
Installation Note If tower is equipped with a side or end suction connection, vent accumulated air from the top of the suction hood by removing one or both tap screws provided at that location. Replace these tap screws when venting is complete. 4. Completely open all hot water flow control valves. Start your pump(s) and observe system operation.
Installation 7. 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 shutdown. Utilize the services of the water treatment supplier.
Operation Tower Operation General: The cold water temperature obtained from an operating cooling 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.
Operation cause the water temperature to rise. When the water temperature then becomes too warm for your process, the motor can be restarted. Caution When operating in this mode care must be taken not to exceed a total acceleration time of 30 seconds per hour. Fan cycling limits: From a dead stop, determine the number of seconds it takes the fan to arrive at full speed. Divide this number into 30 to determine the allowable number of starts per hour.
Operation Note Slushy, transitory ice forms routinely in the colder regions of the fill at low temperature. Such ice normally has no adverse effect on tower operation, but its appearance should be a signal to the operator to undertake ice control procedures. It is the operator's responsibility to prevent the formation of destructive (hard) ice on the cooling tower fill and louvers. Certain guidelines should be followed: 1.
Operation not to prevent it. Reverse fan operation should not need to exceed 1 or 2 minutes. Monitoring is required to determine the time required to melt accumulated ice. Warning Reverse operation of fans for prolonged periods during subfreezing 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 eventually strike this ring of ice, damaging the fan blades or cylinder.
Operation Water Treatment and Blowdown Maintaining Water Quality: The steel used in MD towers has been galvanized with a heavy zinc coating averaging 2.0 mils in thickness. The MD stainless steel option is even more corrosion resistant than galvanized steel in certain environments. Other materials used (PVC fill, drift eliminators, and louvers, aluminum fans, etc.) are selected to offer maximum service life in a “normal” cooling tower environment, defined as follows: Circulating water with a pH between 6.
Operation Cooling Tower Cleaning: Warning Any evaporative-type cooling tower must be thoroughly cleaned on a regular basis to minimize the growth of bacteria, including Legionella Pneumophila, 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.
Maintenance table shows the minimum amount of blowdown (percent of flow) required to maintain different concentrations with various cooling ranges*: Cooling Range Number of Concentrations 1.5X 2.0X 2.5X 3.0X 4.0X 5.0X 6.0X 5° F (2.78° C) .78 .38 .25 .18 .11 .08 .06 10° F (5.56° C) 1.58 .78 .51 .38 .25 .18 .14 15° F (8.33° C) 2.38 1.18 .78 .58 .38 .28 .22 20° F (11.11° C) 3.18 1.58 1.05 .78 .51 .38 .30 25° F (13.89° C) 3.98 1.98 1.32 .98 .64 .48 .
Maintenance SAFETY BRACKET On the MD5016 the motor is located inside the tower plenum. Open the access door (see Access Door Opening Procedure) and hinge out of the way. Caution Any bolts removed functioning as mechanical or structural hardware should be replaced with the torques specified below.
Maintenance the plenum the rod retention is held in place with fasteners. Loosen fastener and slide the bracket away from the adjusting rod. Turn the rod clockwise to drive the motor away from the fan (tighten belts) or counterclockwise to drive the motor toward the fan (loosen the belts). There is no need to loosen any other hardware to adjust the belt tension. After belt tension is adjusted to a satisfactory position, install the rod retention bracket with the thumbscrew and replace any safety hoods.
Maintenance sheave to determine the diameter. If diameter markings are unreadable, measure the sheave diameter at the bottom of the sheave grooves. New belts (operating less than 8 hours) should be tensioned to the maximum value. Tension after this period should use no less than the minimum value. If the belt span was measured in inches, then use the pounds of force values. If the belt span was measured in centimeters, then use the kilograms of force values.
Maintenance Sheave Assembly Bolt Torque Busing Type ft·lbƒ N·m SD 5 10 SK 15 20 SF 25 30 E 35 50 Fan Motor Access and Removal Warning 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.
Maintenance The MD5016 fan motor is located inside the tower. The motor can be accessed through the mechanical access panel. See the Access Door Operation section for instruction on opening the access panel. For greater access to the motor, the motor mounting system can be swung outside the tower to facilitate maintenance and removal. Remove the drive belt by following the instructions in the Belt Tensioning section. Loosen the motor mount system retaining bolts shown in the image.
Maintenance reverse. When fastening the motor mount mechanism to the torque tube, first insert the fasteners closest to the access panel that acts as a hinge. After tightening this hardware, swing the motor in and attach it to the torque tube. Due to the weight of the motor cantilevered on the hinge, the motor mechanism may sag. When attaching to the torque tube, it may be necessary to align the holes with the jacking screw shown in the image.
Maintenance Access Door Operation Warning 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.
Maintenance To remove the eliminator, stand inside the access panel and lift with two hands on an eliminator section, this will indicate where one section stops and another starts. Lift the eliminators at that intersection, removing two packs at one time (see image). Once the first two packs are removed, the remaining packs should be easily removed. Pay close attention to the orientation and placement, they are not symmetrical. Each pack should be replaced at the location which it was removed.
Maintenance Distribution System Maintenance To keep your MD cooling tower operating at peak performance, it may be necessary to clear the spray system of debris or sediment. To access the spray system, remove the drift eliminators as explained in the previous section. Observe the spray system with full flow on the unit. Each nozzle should produce a cone pattern spray which overlaps the adjacent nozzle patterns—see image.
Maintenance arm while pulling out from the header box. When branch arms are removed, access to the interior of the spray header box is available to clean and remove any debris or sediment. A drain nozzle at the centerline of the header box is intended to drain water from the system at shutdown, as well as be removed to wash out the header box if necessary. Be sure to replace this nozzle if removed.
Maintenance Weekly: Inspect for bacterial growth and general operation conditions. Bacterial growth should be reported to your water treatment expert for immediate attention. Monthly (Weekly at start up): Observe, touch, and listen to the tower. Become accustomed to its normal appearance, sound, and level of vibration. Abnormal aspects relating to the rotating equipment should be considered reason to shut down the tower until the problem can be located and corrected.
Maintenance Semi-Annually: Check belt tension and condition. Adjust tensions as necessary. 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—page 20. Consult your water treatment expert as to prudent biological evaluation testing.
Maintenance evidence of a generalized failure of the galvanizing, localized touch-up should be all that is required. Note To the extent that the galvanizing (zinc coating) still exists, paint will not adhere to it readily. Contact the manufacturer of the coating you intend to use for instructions. Tower framework: Check casing and structural bolted connections and tighten as required. Fan: Check fan assembly bolting and tighten as required. Use torque values prescribed in the Fan User Manual.
Maintenance SPX Cooling Technologies Services Our interest in your MD cooling tower does not end with the sale. Having conceived, designed, and manufactured the most reliable and longestlasting cooling tower of its class, we want to make sure that you gain the maximum possible benefit from its purchase.
Maintenance Schedule Maintenance Service Monthly Semi-annually Seasonal Startup or Annually x x Mechanical–motor, fan and drive mechanism x x Makeup valve (if equipped) x x Inspect for unusual noise or vibration x x Air inlet x x PVC drift eliminators x x Nozzles x x Fan motor exterior x x Collection water basin level x x Blowdown–adjust as required x x Inspect General Condition and Operation Observe Operation of: Inspect and Clean: Check: Geareducer Drive (if equipped):
Additional Information Increased load requirements: MD 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: SPX Cooling Technologies routinely rebuilds and upgrades cooling towers of all materials and manufacture.
Troubleshooting Trouble Motor Will Not Start Unusual Motor Noise Cause Power not available at motor terminals • 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.
Troubleshooting Trouble Geareducer Noise Cause Geareducer bearings If new, see if noise disappears after one week of operation. Drain, flush, and refill Geareducer. See Geareducer Service Manual. If still noisy, replace. Gears Correct tooth engagement. Replace badly worn gears. Replace gears with broken or damaged teeth. Loose bolts and cap screws Tighten all bolts and cap screws on all mechanical equipment and supports.
7401 WEST 129 STREET | OVERLAND PARK, KANSAS 66213 UNITED STATES | 913 664 7400 | spxcooling@ct.spx.com | spxcooling.com In the interest of technological progress, all products are subject to design and/or material change without notice. ©2008 SPX Cooling Technologies, Inc.
