background image

12

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. If the fan is intended to be reversed for deicing 
purposes, make sure that the starter is equipped with a 2 minute 
time delay between changes of direction. These delays will prevent 
abnormal stress from being applied to the mechanical equipment 
and the electrical circuit components.

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 Torque Values on page 25.

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.

Tower Startup

Microorganisms including Legionella bacteria can exist in premise 
plumbing including cooling towers. The development of an effective 
water management plan (WMP) and implementation of maintenance 
procedures are essential to prevent the presence, dissemination and 
amplification of Legionella bacteria and other waterborne contami-
nants throughout premise plumbing. Before operating the cooling 
tower, the water management plan and maintenance procedures 
must be in place and regularly practiced. 

Water System:

1.    Consult a knowledgeable water treatment professional to clean and treat 

your new cooling tower prior to startup. Cooling towers must be cleaned 
and disinfected regularly in accordance with ASHRAE Standard 188 and 
Guideline 12.

2.   Do NOT attempt any service unless the fan motor is locked out.

 

Caution

Note

 

Warning

installation

Summary of Contents for MD Series

Page 1: ...MD cooling tower INSTALLATION OPERATION MAINTENANCE Z0602117_F ISSUED 8 2018 READ AND UNDERSTAND THIS MANUAL PRIOR TO OPERATING OR SERVICING THIS PRODUCT user manual ...

Page 2: ...svitalinformationfortheproperinstallationand 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 Note Note 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 pe...

Page 3: ...s 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 Safety First The location and orientation of the cooling tower can affect the safety of those responsible for installing ...

Page 4: ...ley submittal drawings Supports must be level to insure proper operation of the tower 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 t...

Page 5: ...onsist of two modules per cell Both modules have hoisting clips Detailed hoisting drawing are included in the literature package MD upper and lower modules must be hoisted and set separately Do not preassemble modules prior to hoisting A Hoisting Installation label which has hoisting dimensional information is located on the side casing of the tower modules Remove tower from the car rier and hoist...

Page 6: ...wer pickup If damage occurs to the tower due to tie down procedures other than those recommended in the drawing it should be noted upon arrival Remove the protective paper off the sealing gasket tape before setting the top module and ensure there is coverage around the entire perimeter Place the top module on the bottom module aligning mating holes as it is set in place Make sure that the ori enta...

Page 7: ...ions Use gaskets where recommended Do not support your pipe from the tower or outlet connection sup port it externally Normally one of the following three outlet arrangements is provided Side or End suction connection This is a factory installed galvanized pipe nipple extending horizontally from the side or end of the cold water basin It is both beveled for welding and grooved for a mechanical cou...

Page 8: ...ents provided by others that are to be attached to the tower must be compatible with the cooling tower materials e g fasteners in a stainless steel cold water basin must be stainless steel Except for the horizontal components of piping do not support your pipe from the tower inlet connection support it externally Normally one of the following two inlet arrangements is provided Bevel and groove dis...

Page 9: ...bution system serving the motor When using a starter Set motor overload protection to 110 of motor nameplate amps This setting allows the fan motor to operate during cooler weather During cooler weather it is common for the motor to draw 6 to 10 higher than nameplate amps High amps are common during tower commissioning when the tower is dry and the ambient air temperature is cool Do not start the ...

Page 10: ... two speed motor control A VFD can reduce the cost of electrical energy being used and provide better temperature control In addition it reduces the mechanical and electrical stress on the motor and mechanical equipment Electrical savings can be large during periods of low ambient temperature when the cooling requirement can be satisfied at reduced speeds To benefit from these advantages it is imp...

Page 11: ...wer back on 1 Spin the fan manually to assure that all fan blades properly clear the inside of the fan cylinder Observe the action of the sheaves and belts to be sure that the motor is properly aligned with the fan sheave If necessary cor rect the alignment in accordance with the Belt Tensioning and Sheave Alignment section on pages 21 and 24 Thefollowingstepsrequireoperationofthefanmotorwhilethea...

Page 12: ...dicate 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 Tower Startup Microorganisms including Legionella bacteria can exist in premise plumbing including cooling towers The development of an effective watermanagementplan WMP andimpl...

Page 13: ...e system pumps and piping connected to the cooling tower must be configured such that the flowrate supplied to the water inlet of each tower cell does not exceed the maximum design flowrate per cell during startup commissioning or operation Overpumping will result in elevated pressure levels in the tower s water distribution system spray pressures exceeding 8 0 psi may damage the distri bution sys...

Page 14: ...ent period of time residual and time will vary with the biocide to bring the system under good biological control or Treat the system with sodium hypochlorite to a level of 4 to 5 mg L free chlorine residual at a pH of 7 0 to 7 6 The chlorine residual must be held at 4 to 5 mg L for six hours measurable with standard com mercial water test kits If the cooling tower has been in operation and then s...

Page 15: ... 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 3 Water flow rate Increasing the water flow rate gpm will cause a slight elevation in cold water temperature while reducing the water flow rate will caus...

Page 16: ...e 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 Multicell towers equipped with two speed motors will maximize energy savings and minimize sound levels if fans are staged so that all fans are brought ...

Page 17: ... water temperature is established at or near minimum heat load it should be safe for all operating conditions Having established the minimum allowable cold water temperature maintaining that temperature can be accomplished by fan manipulation as outlined in Item 4 under Tower Operation However in towers of more than one cell where fans are manipulated sequentially please realize that the water tem...

Page 18: ...her 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 SPX Cooling Technologies Intermittent Freezing Weather Operation If periods of shutdown nights weekends etc occur...

Page 19: ...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 mg L expressed as CaCO3 Chlorine if used shall be added intermittently with a free residual not to exceed 1 mg L maintained for short periods Excessive chlorine levels may deteriorate sealants and other materials of construction An atmosphere surrounding the tower ...

Page 20: ...tions with various cooling ranges Range Difference between hot water temperature coming to tower and cold water tem perature leaving tower EXAMPLE 700 gpm circulating rate 18 F cooling range To maintain 4 concentrations the required blowdown is 0 458 or 00458 times 700 gpm which is 3 2 gpm If tower is operated at 4 concentrations circulating water will contain four times as much dissolved solid as...

Page 21: ...gularly in accordance with ASHRAE Standard 188 and Guideline 12 Workers performing decontamination procedures must wear personal protective equipment PPE as directed by their facility safety officer Coolingtowersmustbevisuallyinspectedregularlytoassesssignsofbacte rial growth appearance of debris and scale on drift eliminators and general operating conditions Refer to ASHRAE Standard 188 and Guide...

Page 22: ...on top and hinge the hood up and out of the way Also removethemotorsheavesafetybracketandsetaside Seethefollowingimages On the MD5016 thru MD5018 the motor is located inside the tower plenum Open the access door see Access Door Opening Procedure and hinge out of the way Anyboltsremovedfunctioningasmechanicalorstructuralhardware should be replaced with the torques specified below Belt tension on al...

Page 23: ...lockwise to drive the motor toward the fan loosen the belts On modelswithmorethanonerod alternate turns on the rods to prevent binding There is no need to loosen any other hardwaretoadjustthebelttension After belt tension is adjusted to a satisfactory position installtherodretentionbracket with the thumbscrew and replace any safety hoods Ideal tension is the lowest tension at whichthebeltwillnotsl...

Page 24: ...as 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 If specific tensioning instructions are provided with your tensioning tool those instructions should be used instead Sheave Alignment Always shut off electrical power to the tower fan motor prior to performing any inspections that may involve physical contac...

Page 25: ...orce on the fan shaft bearings thus increasing their life Fan Motor Access and Removal 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 pr...

Page 26: ...aining bolts shown in the image It is not necessary to loosen any hard ware other than what is indicated Hinge the motor mounting system 90 out through the access panel Attach a hoist to the motor with straps or chains Lift on the motor slightly with the hoist to remove the weight from the motor fasteners then loosen and remove motor fasteners Hoisting attachment locations vary by motor choose str...

Page 27: ... be removed To remove loosen the thumbscrews indicated in the image below and push the louver retaining bracket up and to the left to move out of the way of the louver frame Tip the top of the frame out from the tower then remove Louver frames are not the same size if more than one louver frame is removed the original location should be noted Collection basin floor has uneven surfaces and has the ...

Page 28: ...at the center of the access door panel 3 Slide the panel with the handle sideways as far as it will travel 4 Push the panel toward the inside of the tower The panel will hinge to the side Drift Eliminator Removal and Replacement The drift eliminators may be removed for cleaning replacement or access to the distribution system The eliminators are held in place by a press fit so there is no need to ...

Page 29: ...orientation and placement they are not symmetrical Each pack should be replaced at the location which it was removed Repeat this process for the second half of the tower Proper eliminator pack replacement is essential to tower operation Incorrect installation may result in excessive drift rates and fan inefficiency To ensure packs are reinstalled in the correct orienta tion it is recommended that ...

Page 30: ...si may damage the distribution system If a nozzle appears clogged or is not producing a cone pattern remove the nozzle and clean all surfaces To remove the nozzle pull down sharply on the plastic component leaving the rubber grommet seated in the PVC pipe Inspect the nozzle for cleanliness or broken pieces Each nozzle should have a turbula tor inside the outer shell see image If the nozzle appears...

Page 31: ...ch arm Schedule of Tower Maintenance Some procedures may require maintenance personnel to enter the tower Each cell has an access door for entry into the tower All tower maintenance can be performed from this location An optional mechanical access platform is designed and intended solely for personnel to gain access to the motor and access door Upon entering the tower the eliminators and fill may ...

Page 32: ... equipment should be considered reason to shut down the tower until the problem can be located and corrected Observe operation of the motor belt sheaves 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 Inspect air inlet louvers drift eliminators and basin trash screens and remove any debris or scale which may hav...

Page 33: ...ere removed Failure to do so may result in diminished thermal capacity Annually Inspect the tower thoroughly making maximum use of instructions given in the separate user manuals Check structural bolted connections and tighten as required Make preventive maintenance repairs as necessary Lubricate motor according to the manufacturer s instructions Motors with sealed bearings do not require lubricat...

Page 34: ...ed 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 Fan shaft bearings Lubricate fa...

Page 35: ...t one or more of the various Marley plants In cases of emergency they can normally be shipped within 24 hours by air freight if necessary However you would obviously benefit from anticipating your need in advance thus avoiding 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 ...

Page 36: ...and operation of the cooling tower Field installation is always required for fan guards piping inlets and piping outlets Some optional accessories such as valves handrails ladders and safety cages may also require field installation If installation details are not covered in the MD Field Installation Manual a separate installation drawing or manual for each purchased option is included in the docu...

Page 37: ...nes if equipped Check for oil leaks in hoses or fittings x R x Belt drive Fan shaft bearing lubrication every 3 mo every 3 months every 3 months Check and tighten support fasteners x Check shaft sheave and belt alignment x Check belt tension and condition x x Check sheave bushing fastener torque x Fan Check and tighten blade and hub fasteners x Check fan blade pitch and tip clearance x Check fan c...

Page 38: ...cket fits or bearing Rotor unbalance Rebalance Cooling fan hitting end bell guard Reinstall or replace fan Motor runs hot Wrong voltage or unbalanced voltage Check voltage and current of all three lines against nameplate values Overload Check fan blade pitch See Fan User Manual Check for drag in fan drivetrain as from damaged bearings Wrong motor RPM Check nameplate against power supply Check RPM ...

Page 39: ...motor If motor still vibrates rebalance motor Bent Geareducer shaft Check fan and pinion shaft with dial indicator Replace if necessary Fan noise Blade rubbing inside of fan cylinder Adjust cylinder to provide blade tip clearance Loose bolts in blade clamps Check and tighten if necessary Scale or foreign substance in circulating water system Insufficient blowdown See Water Treatment section of thi...

Page 40: ...ESERVED In the interest of technological progress all products are subject to design and or material change without notice MD cooling tower US E R MAN UAL SPX COOLING TECHNOLOGIES INC 7401 WEST 129 STREET OVERLAND PARK KS 66213 USA 913 664 7400 spxcooling spx com spxcooling com ...

Reviews: