Marley AV CoolingTower
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User Manual 98-1514E
Preparation
The Marley AV Series cooling tower purchased for this installation repre-
sents the current state of the art in crossflow, 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,
float valves, etc.—are intended to assure that the tower serves you prop-
erly for the maximum possible time. Since product warrantability may
well depend upon your actions, please read these instructions thoroughly
prior to operation.
If you have questions about the operation and/or maintenance of this
tower, and you don’t find the answers in this manual, please contact your
Marley sales representative. When writing for information, or when order-
ing parts, please mention tower serial number shown on the nameplate
located on the access door.
Safety First
The location and orientation of the cooling tower can affect the safety of
those responsible for installing, operating or maintaining the tower. How-
ever, since SPX Cooling Technologies does not determine the location or
orientation of the tower, we cannot be responsible for addressing those
safety issues that are affected by the tower’s location or orientation.
WarNiNg
Thefollowingsafetyissuesshouldbeconsideredbythoseresponsible
for designing the tower installation.
Warning
• access to and from maintenance access doors
• the possible need for ladders (either portable or permanent) to gain
access to the distribution basin or maintenance access doors
• the possible need for distribution basin platforms
• potential access problems due to obstructions surrounding the
tower
• lockout of mechanical equipment
• the possible need for safety cages around ladders
• the need to avoid exposing maintenance personnel to the poten-
tially unsafe environment inside the tower.
It is not intended nor assumed that access to the fan deck is needed
Note
or necessary.
3
Preparation
Those are only some of the safety issues that may arise in the design
process.SPXstronglyrecommendsthatyouconsultasafetyengineer
to be sure that all safety considerations have been addressed.
Note
Several options are available that may assist you in addressing some of
these personnel safety concerns, including:
—distribution basin access platform with ladder and handrail
—ladder extensions for distribution basin platform ladders (used where
the base of the tower is elevated)
—safety cages for distribution basin platform ladders
—mechanical equipment access platform and ladder
—fan cylinder extensions
—flow control valve
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. If you have questions about the adequacy of the avail-
able space and the intended configuration of the tower, please contact
your Marley sales representative for guidance.
Prepare a stable, level support foundation for the tower, utilizing weight,
wind load, and dimensional information appearing on appropriate Marley
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
avoidthepossibilityofcontaminatedtowerdischargeairbeingdrawn
into building fresh air intake ducts. The purchaser should obtain the
services of a Licensed Professional Engineer or Registered Architect
to certify that the location of the tower is in compliance with appli-
cable air pollution, fire, and clean air codes.
Warning
4
Receiving and Hoisting
Tower Shipment
Unless otherwise specified, AV Series towers ship by truck (on flat bed
trailers), which lets you receive, hoist, and install the tower in one con-
tinuous operation. Single-cell towers ship on one truck. Multicell towers,
depending on their size, may require more than one truck.
Responsibility for the condition of the tower upon its arrival belongs to the
trucker—as does the coordination of multiple shipments, if required.
receiving Tower
Prior to unloading the tower from the delivering carrier, inspect the ship-
ment for evidence of damage in transit. If damage is apparent, note the
freight bill accordingly. This will be needed to support any future recovery
claim.
Find and remove the installation instruction drawings and bills of material
(literature kit) located in a plastic bag in the cold water basin. This informa-
tion should be kept for future reference and maintenance purposes.
Hoisting Tower
AV6300throughAV6700modelsconsistoftwomodulespercell.Theupper
module includes hoisting clips at the top of the module. The hoisting clips
on the lower module are located near the bottom on the ends of the cold
water basin. All other models ship in a single module. The hoisting clips
for the single height models, AV6100 and AV6200, are located at the top
of the tower. A Hoisting-installation label is located on the side casing
near the access door and on a drawing in the literature kit. Remove tower
from the carrier and hoist into place according to the instructions on the
label or on the drawing.
Hoisting clips are provided for ease of unloading and positioning
tower. For overhead lifts or where additional safety is required, safety
slingsshouldalsobeplacedunderthetower.Undernocircumstances
should you combine the top and bottom modules of AV6300 through
AV6700 models and attempt to hoist them at the same time by utiliz-
ing the hoisting clips alone!
Warning
5
Installation
Tower installation
Theseinstallationinstructionsareintendedtohelpyoupreparebefore
your tower arrives. If discrepancies exist between these instructions
and those shipped with the tower, the instructions shipped with the
tower will govern.
Note
1. Prior to placement of the tower, confirm that the supporting platform
is level, and that the anchor bolt holes are correctly located in accor-
dance with Marley drawings.
2. Place tower (or bottom module of AV6300 through AV6700) on your
prepared supports, aligning anchor bolt holes with those in your sup-
porting steel. Make sure that the orientation agrees with your intended
piping arrangement. Attach tower to supporting steel with four 1⁄2" (13
mm) diameter bolts and flat washers (by others). Position flat washers
between the bolt head and the tower basin flange.
Remove the sheet metal fill protector shields from the bottom of the
Note
Note
top module before setting in place.
3. aV6300throughaV6700modelsonly. Removeshippingguardsfrom
bottom of top module (AV6500 thru AV6700). Clean any debris from
the underside of the top module fill, skid and beams and from the top
of the bottom module before hoisting into place.
Remove paper backing form sealer strips around top perimeter of
bottom module.
Place top module on the top peripheral bearing surface (factory-
installed gasket) of bottom module, aligning mating holes as it is set in
place. Attach top module to bottom module with fasteners provided—
according to Field Installation Manual instructions.
If tower purchased is one cell only, ignore steps 4 through 8.
4. If collection basins are to be equalized by the use of Marley standard
flumes, unbolt the temporary coverplate from the basin of the cell just
installed. The coverplate is located on the basin side.
5. Unbolt temporary coverplate from the basin of the 2nd cell and set
2nd cell (or bottom module of 2nd cell) in place. Align anchor bolt
holes and flume openings in basin sides.
6. Install flume according to Field Installation Manual instructions.
6
Installation
It is important that the cells be firmly anchored and aligned before
the flume is attached to the 2nd cell.
Note
7. Repeat steps 2 and 3 for 2nd top section on AV63000 thru AV67000
models.
8. Repeat steps 4 through 7 for any remaining cells.
9. Attach your cold water supply piping to the cold water basin outlet
connection in accordance with drawing instructions, and utilizing
gaskets provided by Marley.
Donotsupportyourpipefromthetoweroroutletconnection—support
Caution
it externally.
Normally, one of the following three outlet arrangements is provid-
ed:
Cased face or air inlet face 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 coupling. If a weld connection is used, it
is recommended that the weld area be protected against corrosion.
Coldgalvanizingissuggested,appliedaccordingtothemanufacturer’s
instructions.
Bottom outlet connection: This is a factory-installed, screened cir-
cular opening in the cold water basin floor of one or more cells. An
appropriately-sized circular opening has been drilled to accept a 125#
ANSI B16.1 flat-face flange connection.
10. Attach makeup water supply piping to the float valve connection
located at the air inlet face of the tower. If you wish to pipe overflow
and drain water to a remote discharge point, make those connections
at this time.
11. Attach your warm water return piping to the inlet connections of the
tower.
Do not support your pipe from the tower or inlet connection—support
Caution
it externally.
➠
7
Installation
Normally, one of the following two inlet arrangements is provided:
Standarddistributionbasinconnections:Thereisacircularopening
in the top deck of the tower near the air inlet face, drilled to accept
standard 125# flat-face flange. Remove the center inlet flume as-
sembly to gain access to attach inlet fasteners. (Refer to the AV Field
Installation Manual shipped with tower.)
Marley flow-control valve connection (option): The Marley flow-
control valve is designed to 1–take the place of a standard elbow
normally required for inlet connection, and 2–provide means of regu-
lating flow between individual cells. Remove the center inlet flume
assembly to gain access for attachment of valve. (Refer to the AV
Field Installation Manual shipped with tower.) The valves provides a
vertical face for attachment of your standard 125# flange.
12. Wiremotorinaccordancewithwiringdiagramonmotornameplate.
Check motor connections and power supply voltage versus motor
nameplate voltage.
Formaintenance/safetypurposes,SPXCoolingrecommendsalockout
type disconnect switch for all mechanical equipment.
Warning
In addition to a disconnect switch, the motor should be wired to main
power supply through short circuit protection, and a magnetic starter
with overload protection.
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.
This setting allows the fan motor to operate during cooler weather.
During cooler weather it is common for the motor to draw 6 to
8
Installation
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 motor more than six times per hour. Short cycling
the tower will cause fuses, breakers or O.L.s to operate and will
decrease motor life.
When using a two-speed starter:
• Motor rotation must be the same at slow speed and high speed.
• Single winding motor requires a starter with a shorting contactor.
• Two-winding motor requires a starter with out a shorting contac-
tor.
• All two-speed starters must have a 20 second time delay relay
when switching from high speed to low speed.
• Do not start the motor more than six times per hour (each low
speed start and each high speed start count as one start).
When using a VFD:
Before beginning, ensure that the motor is rated for “Inverter Duty”
per NEMA MG-1, part 31.
Note
• Set the VFD solid state overload protection to 119% of motor
nameplate amps and set “maximum current parameter” in the
VFD to motor nameplate amps. “Maximum current parameter” will
reduce fan speed and limit amp draw to nameplate amps during
cold weather operation. If furnished with a mechanical O.L. set this
at 110% over motor nameplate amps.
• Motor rotation must be the same in both VFD mode and By-pass
mode.
• 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 con-
stant torque modes may damage the gearbox.
• Donotstartandstopthemotorusingthesafetyswitchatthemotor.
If the drive is being commanded to run and the load side is cycled
ON and OFF with the safety switch this may damage the VFD.
Using a VFD in cooling applications has advantages over traditional single
or two speed motor control. A VFD can reduce the cost of electrical en-
➠
9
Installation
ergy 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 important that the drive
be installed correctly.
MarleysuppliesVFDandVFDcontrolsspecificallydesignedforourcooling
products. If you have purchased a Marley VFD and/or controls package,
please follow the instructions in the User Manual for that system. Most
VFD problems can be avoided by purchasing the Marley drive system. If
you are installing a VFD other than the Marley drive, please refer to that
drives installation manual.
Improper use of a VFD may cause damage to equipment or personal
injury. Failure to correctly install the VFD drive will automatically void
all warranties associated with the motor and any equipment that is
either electrically or mechanically (directly) attached to the VFD drive
system. The length of this warranty avoidance will be contingent on
properlyinstallingtheVFDsystemandrepairinganydamagethatmay
have occurred during its operation. SPX Cooling Technologies does
not assume responsibility for any technical support or damages for
problems associate with non-Marley brand VFD systems.
Warning
Changing the operational fan speed from the factory settings could
cause the fan to operate in an unstable region which may result in
damage to the equipment and possible injury.
Warning
Warning
Mechanical Equipment:
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. Install AV61000 and AV62000 fan guard according to the installation
drawing shipped with the tower. The fan guard on other models is
factory installed.
2. 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 belt(s)
to be sure that the motor is properly aligned with the fan sheave. If
10
Installation
necessary, correct the alignment. See the Maintenance section for
belt tensioning and sheave alignment—page 22.
Improper installation of the fan guard will destroy the structural in-
tegrity of the fan guard. It is essential that the fan guard be installed
in accordance with the Field Installation Manual shipped with the
tower. Do not force the fan cylinder out of round.
Warning
3. Momentarily energize (“bump”) the motor and observe rotation of the
fan.Thefanshouldrotateinacounterclockwisedirectionwhenviewed
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. 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.
Caution
4. Run the motor and observe the operation of the mechanical equip-
ment. Operation should be stable.
5. After the first 30 minute run check motor AMPS and voltage with full
water and heat load. Repitch fan, if necessary—correct for low ambi-
ent temperatures. Refer to motor manual.
6. After 10 to 60 hours of operation check the torque on the fan and
motor sheave bushings and check belt tension. Refer to the Main-
tenance section of this manual for torque values and belt tensioning
instructions—page 22.
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. Determi-
nation of an accurate motor load should await the application of the
design heat load.
Note
11
Operation
Tower Start-Up
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.
Warning
Water System:
1. New installations 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
attention to inside areas of cold water basin, hot water basins, louvers
and drift eliminators. Make sure that cold water suction screens are
clear and properly installed.
3. Fill the water system to an approximate depth of 71⁄2" (192 mm) in
the depressed area of the cold water basin at the air inlet side of the
tower. This is the recommended operating water level. Adjust the float
valve so that it is 75% open at that level. Continue filling the system
until the water reaches a level approximately 1⁄8" (3 mm) below the lip
of the overflow.
If tower is equipped with a standard suction connection, vent ac-
cumulated 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.
Note
4. Completely open hot water flow control valve(s). Start your pump(s)
and 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.
Some trial-and-error adjustment of the float valve may be required to
12
Operation
balance the makeup water with tower operation. Ideally, the float valve
setting will be such that no water is wasted through the overflow at
pump shutdown. However, the water level after pump start-up must
be deep enough to assure positive pump suction.
5. If a multicell tower installation is equipped with flow-control valves,
adjust them to equalize hot water depth in the distribution basins after
reaching design water flow rate. Each basin should have from 23⁄4" to
51⁄2" (70 mm to 140 mm) water depth, with uniform depth from basin
to basin. Fix valves in this position when depth is correct. If the tower
is a single cell installation this step is not necessary.
Uniformdistributiondepthof23⁄4"to51⁄2"(70mmto140mm)isessential
to efficient tower operation. Contact your Marley sales representative
if you are considering a permanent change in circulating water flow
rate that would prevent operation within these limits.
6. Continue pump operation for about 15 minutes, after which it is rec-
ommended that the water system be drained, flushed, and refilled.
7. While operating the condensing water pump(s) and prior to operat-
ing 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.
Maintain the maximum recommended biocide residual (for the
specific biocide) for a sufficient 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
(ppm) free chlorine residual at a pH of 7.0 to 7.6. The chlorine re-
sidual 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
duration 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
stagnantwateroverthecoolingtowerfilloroperatingthecoolingtower
fan. After biocidal pretreatment has been successfully completed,
cooling water may be circulated over the tower fill with the fan off.
➠
13
Operation
Whenbiocidaltreatmenthasbeenmaintainedatasatisfactorylevelfor
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.
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.
Note that 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
=
GPM x 500
or — in SI units
Heat Load (kilowatts)
Liters/sec x 4.187
Range – °C
=
The cooling tower establishes only the cold water temperature attain-
able under any operating circumstance.
2. 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 (11 °C) reduction
in wet-bulb may result in only a 15°F (8°C) reduction in cold water
temperature.
3. Water flow rate: Increasing the water flow rate (GPM or L/s) will cause
a slight elevation in cold water temperature, while reducing the water
flow rate will cause the cold water temperature to decrease slightly.
However, at a given heat load (see formula above), water flow reduc-
tions also cause an increase in the incoming hot water temperature.
Use care to prevent the hot water from exceeding 125°F, (52°C) in
14
Operation
order to prevent damage to the tower components.
4. 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.
When operating in this mode care must be taken not to exceed a total
Caution
acceleration time of 30 seconds per hour.
Fan cycling limits: From a dead stop, determine the number of sec-
onds it takes the fan to arrive at full speed. Divide this number into 30
to determine the allowable number of starts per hour. Considering the
normal fan and motor sizes utilized on AV Series towers, anticipate
that approximately 4 to 5 starts per hour are allowable.
Ifyourtowerisequippedwithatwo-speedmotor,youwillenjoygreater
opportunity for temperature control. When the water temperature
becomes too cold, switching the fan to half-speed will cause the cold
water temperature to rise—stabilizing at a temperature a few degrees
higher than before. With a further reduction in water temperature, the
fan may be cycled alternately from half-speed to off—subject to the
same constraint of 30 seconds of allowable acceleration time per hour
as outlined above.
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 temperature control, please read
“Cooling Tower Energy and its Management”, Marley Technical
Report #H-001-A, available at spxcoolling.com.
15
Operation
Wintertime Operation:
The Marley fill system used in the AV Series cooling tower has air entrance
louvers that are molded integrally as part of the fill. This feature makes
these towers very forgiving of cold weather operation, even at the low
temperature and reduced load conditions encountered in free cooling
and other low temperature applications. Nevertheless, during operation
in subfreezing weather the opportunity exists for ice to form in the colder
regions of the tower.
Slushy, transitory ice forms routinely in the colder regions of the fill
of low temperature towers, and is visible through the tower louvers.
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.
Note
It is the operator's responsibility to prevent the formation of destruc-
tive (hard) ice on the cooling tower fill. Certain guidelines should be
followed:
1. Do not allow the tower’s leaving water temperature to drop below a
minimum allowable level—say 36°F to 40°F (2°C to 4.5°C). If such
low temperature operation is necessary or beneficial to your process,
establish the minimum allowable level as follows:
Duringthecoldestdaysofthefirstwinterofoperation,observewhether
any ice is forming on the louver face, particularly near the bottom
part of the louver face. If hard ice is present on the louvers, you must
increase the allowable cold water temperature. 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 condi-
tions.
Caution
Having established the minimum allowable cold water temperature, main-
taining 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 temperature will be significantly lower in the cell or cells
operating at the highest fan speed than the net cold water temperature
16
Operation
produced by the entire tower would indicate. Wintertime operation of
multicell towers at low cold water temperature levels requires that the
operator be especially watchful.
2. As cold air enters the louvers, it causes the water flowing over the fill
to be drawn inward toward the center of the tower. Thus, under fan
operation,thelouversandlowerperipheryofthetowerstructureremain
partly dry, seeing only random splashing from within the tower—plus
normalatmosphericmoisturefromtheenteringair. Suchlightlywetted
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.
3. Under extended extreme cold conditions, it may be necessary to op-
erate the fan in reverse. This forces warm air out through the louvers,
melting any accumulated ice—adequate heat load must be available.
Reversal may be at either full or half speed; however, SPX Cooling
recommends reversal at half speed. 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. Monitoring 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 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. 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 operation dur-
ing subfreezing weather to permit ice to dissipate from fan blades
and fan cylinders. See Caution note on page 11 for fan speed change
and reversing precautions.
Warning
➠
17
Operation
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 SPX Cooling engineers.
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 wa-
ter basin—and all exposed pipework—from freezing. Several methods
are used to combat this, including Marley automatic basin heater sys-
tems.
Unless some means of freeze prevention is incorporated into your
system, the tower basin and exposed pipework should be drained at
the beginning of each wintertime shutdown period.
Caution
Warning
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.
18
Operation
Tower Cleaning, Water Treatment and Blowdown
Maintaining Water Quality:
The steel used in AV Series towers has been galvanized with a heavy zinc
coatingaveraging2.0milsinthickness. AVSeriestowersarealsoavailable
in stainless steel, which is even more corrosion resistant than galvanized
steelincertainenvironments.Othermaterialsused(PVCfill,drifteliminators,
and louvers, aluminum fans, etc.) are selected to offer maximum service
life in a “normal” cooling tower environment, defined as follows:
CirculatingwaterwithapHbetween6.5and8;achloridecontent(asNaCl)
below 500 ppm; a sulfate content (SO4) below 250 ppm; total alkalinity
(as CaCO ) below 500 ppm; calcium hardness (as CaCO ) above 50 ppm;
3
3
a maximum inlet water temperature not to exceed 125°F (51.7°C); no
significant contamination with unusual chemicals or foreign substances;
and adequate water treatment to minimize scaling.
• 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 ).
3
• Chlorine (if used) shall be added intermittently, with a free residual not
to exceed 1 ppm—maintained for short periods. Excessive chlorine
levels may deteriorate sealants and other materials of construction.
• 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 (H2S).
• Many proprietary chemicals exist for control of scale, corrosion, and
biological growth and should be used prudently. Also, combinations
of chemicals may cause reactions which reduce treatment effective-
ness, and certain chemicals such as surfactants, biodispersants and
antifoams may increase drift rate.
Unless you purchased a stainless steel AV Series the structure of
your AV Series consists primarily of galvanized steel, therefore your
water treatment program must be compatible with zinc. In working
with your water treatment supplier, it is important that you recognize
the potential effects on zinc of the specific treatment program you
choose.
Warning
19
Maintenance
Cooling Tower Cleaning:
Any evaporative-type cooling tower must be thoroughly cleaned on
a regular basis to minimize the growth of bacteria, including Legio-
nella 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.
Warning
Operators of evaporative cooling equipment, such as water cooling tow-
ers, should follow maintenance programs which will reduce to an abso-
lute 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 a complete water treatment program including biocidal treatment. See
Tower Startup instructions on page 12.
The visual inspection should take place at least once a week during the
operating season. The periodic flushing and cleaning should be done be-
fore and after each cooling season, but in any event at least twice a year.
The 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
installedandmaintained.Filtrationdevicesmaybeemployedtoreducethe
suspended solids concentrations, thus increasing the effectiveness of the
water treatment program. See Tower Startup instructions on page 12.
Blowdown:
A cooling 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.
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 treatment company must work from a relatively constant level of
20
Maintenance
concentrations. This stabilization of contaminant concentrations is usually
accomplished by blowdown, which is the constant discharge of a portion of
Number of Concentrations
Cooling Range
1.5X
2.0X
2.5X
3.0X
.18
.38
.58
.78
.98
4.0X
.11
.25
.38
.51
.64
5.0X
.08
.18
.28
.38
.48
6.0X
.06
.14
.22
.30
.38
5° F (2.78° C)
10° F (5.56° C)
15° F (8.33° C)
20° F (11.11° C)
25° F (13.89° C)
.78
.38
.25
1.58
2.38
3.18
3.98
.78
.51
1.18
1.58
1.98
.78
1.05
1.32
Multipliers are based on drift of 0.02% of the circulating water rate.
the circulating water to waste. As a rule, acceptable levels on which to base
atreatmentschedulewillbeintherangeof2-4concentrations.Thefollowing
table shows the minimum amount of blowdown (percent of flow) required
to maintain different concentrations with various cooling ranges*:
*
Range = Difference between hot water temperature coming to tower and cold water
temperature leaving tower.
EXaMPLE: 700 GPM (44.2 L/s) circulating rate, 18°F (10°C) cooling range.
To maintain 4 concentrations, the required blowdown is 0.458% or .00458
times 700 GPM (44.2 L/s), which is 3.2 GPM (0.2 L/s).
If tower is operated at 4 concentrations, circulating water will contain four
times as much dissolved solid as the makeup water, assuming none of the
solids form scale or are otherwise removed from the system.
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.
Note
Belt Tensioning
The belts are adjusted by turning the jacking screw at the motor support.
Ideal tension is the lowest tension at which the belt will not slip under
peak load conditions. Check tension frequently during the first 24-48
hours of run-in operation. Overtensioning shortens belt and bearing
life. Keep belts free from foreign material which may cause slip. Never
apply belt dressing as this will damage the belt and cause early failure.
®
A Dodge V-Belt Tension Tester is an alternate method for tensioning
V-belts. Check with you local belt supplier.
➠
21
Maintenance
Sheave alignment
• The motor sheave is to be positioned as close as possible to the motor
in order to minimize torque on the motor bushings.
• The motor and fan sheaves may have grooves that are not used. The
bottom surface of the motor and fan sheaves must be aligned within
1
⁄
8" of each other and level within 1⁄2° (1⁄8" in 12) in order to not adversely
affect belt and sheave life.
• Alignment can be achieved by placing a straight edge across the top
of the sheaves making sure that it is level and measuring down to the
bottom surface of both sheaves at four points.
• The belt is to be located in the lowest set of grooves.
Torque
Bushing
Fastener Size
ft· lbƒ
N· m
56M - 20
56M - 20
56M - 20
ꢀ6QE - 18
ꢁ6 - 16
56O - 13
ꢂ6QE - 12
SH
SDS
SD
SK
SF
E
6
6
8
8
6
8
13
22
35
65
18
30
48
88
F
Bushing Fastener Torque Values
22
Maintenance
Schedule of Tower Maintenance
Somemaintenanceproceduresmayrequiremaintenancepersonneltoenter
the tower. Each cased face of the tower has a door for access to the interior
of the tower. All AV Series have a 30″ wide by 42″ high door opening.
The purchaser or owner is responsible for providing a safe method
for entering or exiting the access door. Protective clothing to avoid
cuts from sheet metal should be worn. Wet sheet metal an/or dirt can
be slippery. Nonslip sole shoes should also be worn.
Included with this 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 main-
tenance:
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.
Warning
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 vi-
bration. Abnormal aspects relating to the rotating equipment should be
consideredreasontoshutdownthetoweruntiltheproblemcanbelocated
and corrected. Observe operation of the motor, sheaves, belt, 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 louvers, drift eliminators and basin trash screens and remove any
debris or scale which may have accumulated. Replace any damaged
➠
23
Maintenance
or worn out components. Use of high-pressure water may damage the
eliminator and louver material.
Observe operation of the float valve. Depress the operating lever to make
sure that the valve is operating freely. Inspect the suction screen for plug-
ging. Remove any debris that may have accumulated.
Check for any buildup of silt on the floor of the cold water basin. Mentally
make note of the amount, if any, so future inspections will enable you to
determine the rate at which it is forming.
Every 3 months: Lubricate fan shaft bearings. While rotating equipment
by hand, grease the bearings until a bead forms around the seals—a
maximum charge of 0.55 ounces is recommended. Chevron SRI-2 grease
is recommended.
Every 6 months: Check belt tension and condition.
Check makeup float valve seals—replace as required.
If equipped with inlet flow control valve, grease valve stem guide—fully
open and close—return to original position and lock.
Clean and disinfect cooling tower with biocides. Systems with biofoul-
ing, high general bacterial counts, or positive cultures of legionella may
require additional cleaning. Refer to Cooling Tower Cleaning section
on page 19 Consult your water treatment expert as to prudent biological
evaluation testing.
If basin silt level is significant, drain the basin and clean it out. Refer to
Cooling Tower Cleaning section on page 19.
annually:Relubricatemotor.Refertomotormanufacturer’s recommenda-
tions. Remove grease fill and relief plugs from front of motor and remove
hardened grease with a wire or similar item, Add grease until grease is
1
forced out at relief hole. Replace fill plug, run ⁄2 to 1 hour and replace
relief plug.
Check to see that all bolts are tight in the fan and mechanical equipment
region, including the fan cylinder and fan guard. Use torque settings pre-
scribed in the fan manual.
Inspect the tower thoroughly, making maximum use of instructions given
in the separate service manuals. Check structural bolted connections and
tighten as required. Make preventive maintenance repairs as necessary.
24
Maintenance
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 drains open.
During shutdown, clean the tower (see Warning, page 20) and make any
necessary repairs. Pay particular attention to mechanical equipment.
Following each year’s shutdown and cleaning, inspect the tower’s metal
surfaces for evidence of the need to apply a protective coating. Do not
misinterpret grime—and transient rust from the piping system—as a need
to have the tower painted. If relatively bright metal can be exposed by
cleaning,considerthatthegalvanizinghasremainedeffective.Unlessthere
is evidence of a generalized failure of the galvanizing, localized touch-up
should be all that is required.
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 structural bolted connections and tighten as
required.
Fans: Check fan assembly bolting and tighten as required. Use torque
settings prescribed in the fan manual.
Fiberglass Components: Check all fiberglass parts for exposed glass
fibers. If found, the affected surfaces should be recoated using a two-
part polyamide epoxy primer to promote adhesion and a two-part acrylic
polyurethane enamel for the topcoat.
Fan shaft bearings: Lubricate fan shaft bearings at close of each operat-
ing season—see page 24.
Electric motors: Clean and lubricate motor at close of each operating
season (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 User Manual 92-1475.
At start of new operating season, make sure bearings are adequately
25
Maintenance
lubricated before returning motor to service.
Prolonged Shutdown
If shutdown period is longer than seasonal, contact your Marley sales
representative for additional information.
SPX Cooling Technologies’ Services
Our interest in your AV Series cooling tower does not end with the sale.
Having conceived, 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: as-
sure 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, drive system, and
floatvalve,everystandardcomponentofyourtowerisdesignedandmanu-
factured 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.
Acompletestockofallpartsandcomponentsismaintainedatoneormore
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 include your tower serial number (from the tower nameplate)
when ordering parts.
Periodic maintenance: You may wish to contract with SPX Cooling for
regularlyscheduledvisits—forthepurposeofinspectingandreportingyour
tower’s condition—to make recommendations intended to prevent emer-
gencies— 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 recognize 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.
26
Maintenance Schedule
Maintenance Service
Inspect General Condition and Operation
Observe Operation of:
Monthly
Semi-annually
Seasonal Startup or annually
x
x
x
x
x
x
x
x
Mechanical–motor, fan and drive mechanism
Makeup valve (if equipped)
Inspect for unusual noise or vibration
inspect and Clean:
x
x
x
x
x
x
x
x
Air inlet
PVC drift eliminators
Distribution basin, nozzles and collection basin
Fan motor exterior
Check:
x
x
x
x
Collection water basin level
Blowdown–adjust as required
Belt drive:
Fan shaft bearing lubrication (every 3 mo.)
Check and tighten support fasteners
Check shaft, sheave and belt alignment
Check belt tension and condition
Check sheave bushing fastener torque
Fan:
every 3 months
every 3 months
x
x
x
x
x
x
x
x
Check and tighten blade and hub fasteners
Check fan blade pitch and tip clearance
Check fan cylinder for loose fasteners
Motor:
R
Lubricate (grease as required)
Check mounting bolts for tightness
Operate at least
x
3 hours a month
3 hours a month
3 hours a month
Basin Heater (if equipped):
Check for proper operation of temp/low water level sensor
Inspect/clean buildup of contaminant from sensor
Structure:
x
x
x
x
x
x
Inspect/tighten all fasteners
Inspect and touch up all metal surfaces
R — Refer to Component User Manual
Note: It is recommended at least weekly, that the general operation and condition be observed. Pay
attention to any changes in sound or vibration that may signify a need for closer inspection.
27
Troubleshooting
Trouble
Cause
Remedy
•
Check power at starter. Correct any bad connections
between the control apparatus and the motor.
Check starter contacts and control circuit. Reset overloads,
•
Power not available at motor terminals
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.
Wrong connections
Low voltage
Check motor and control connections against wiring diagrams.
Motor Will Not Start
Check nameplate voltage against power supply. Check
voltage at motor terminals.
Open circuit in motor winding
Motor or fan drive stuck
Rotor defectve
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.
Motor running single-phase
Motor leads connected incorrectly
Bad bearings
Check motor connections against wiring diagram on motor.
Check lubrication. Replace bad bearings.
Check voltages and currents of all three lines. Correct if
required.
Unusual Motor Noise
Electrical unbalance
Air gap not uniform
Check and correct bracket fits or bearing.
Rebalance.
Rotor unbalance
Cooling fan hitting end bell guard
Reinstall or replace fan.
Check voltage and current of all three lines against nameplate
values.
Wrong voltage or unbalanced voltage
Check fan blade pitch. See Fan Manual. Check for
drag in fan drive train as from damaged bearings.
Overload
Wrong motor RPM
Bearings overgreased
Check nameplate against power supply. Check RPM of motor.
Remove grease reliefs. Run motor up to speed to purge
excessive grease.
Change to proper lubricant. See motor manufacturer's
instructions.
Wrong lubricant in bearings
One phase open
Stop motor and attempt to start it. Motor will not start if single-
phased. Check wiring, controls, and motor.
Motor Runs Hot
Dirty motor
Clean motor.
Winding fault
Check with Ohmmeter.
Bent motor shaft
Insufficient grease
Straighten or replace shaft.
Remove plugs and regrease bearings.
Limit cumulative acceleration time to a total of 30 seconds/hr.
Set on/off or speed change set points farther apart. Consider
installing a Marley VFD drive for fine temperature control.
Too frequent starting or speed changes
Deterioration of grease, or foreign
material in grease
Flush bearings and relubricate.
Replace bearings.
Bearings damaged
Check transformer and setting of taps. Use higher voltage on
transformer terminals or reduce loads. Increase wire size or
reduce inertia.
Voltage too low at motor terminals
because of line drop
Motor Does Not Come Up
To Speed
Look for cracks near the rings. A new rotor may be required.
Have motor service person check motor.
Broken Rotor bars
Wrong Rotation (Motor)
Wrong sequence of phases
Switch any two of the three motor leads.
28
Troubleshooting
Trouble
Cause
Remedy
Tighten all bolts and cap screws on all mechanical equipment
and supports.
Loose bolts and cap screws
Make certain all blades are as far from center of fan as safety
devices permit. All blades must be pitched the same. See
Fan User Manual. Clean off deposit build-up on blades.
Fan
Unusual Fan Drive
Vibration
Worn fan shaft bearings
Unbalanced motor
Check fan shaft endplay. Replace bearings as necessary.
Disconnect load and operate motor. If motor still vibrates,
rebalance rotor.
Blade rubbing inside of fan cylinder
Loose bolts in blade clamps
Fan shaft bearings
Adjust cylinder to provide blade tip clearance.
Check and tighten if necessary.
Grease bearings.
Fan Noise
Insufficient blowdown
See "Water Treatment" section of this manual
Scale or foreign substance
in circulating water system
Consult competent water treating specialist. See "Water
Treatment" section of this manual
Water treatment deficiency
Check to see if local heat sources are affecting tower. See if
surrounding structures are causing recirculation of tower
discharge air. Discuss remedy with Marley representative.
Entering wet bulb temp. is above design
Design wet bulb temp. was too low
May have to increase tower size. Discuss remedy with Marley
representative.
Cold Water Temperature
Too Warm
(See "Tower Operation")
May have to increase tower size. Discuss remedy with Marley
representative.
Actual process load greater than design
Overpumping
Reduce water flow rate over tower to design conditions.
Check motor current and voltage to be sure of correct contract
horsepower. Re-pitch fan blades if necessary. Clean louvers,
fill and eliminators. Check to see if nearby structures or
enclosing walls are obstructing normal airflow to tower.
Discuss remedy with Marley representative.
Tower starved for air
Reduce water flow rate over tower to design conditions. Be
sure hot water basin nozzles are in place and not plugged.
Distribution basins overflowing
Faulty drift elimination
Check to see that integral fill, louvers, and eliminators are
clean, free of debris, and installed correctly. If drift eliminators
are separate from fill, make sure they are correctly installed in
place. Clean if necessary. Replace damaged or worn out
components.
Excessive Drift Exiting
Tower
29
Additional Information
increased load requirements: AV Series towers are designed such 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 up-
grades cooling towers of all materials and manufacture. If your tower 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.
Each AV tower includes a document package containing general
orientation drawings, a Field Installation Manual, and tower component
usermanuals.Thesedocumentscontainimportantinformationrelating
to safe installation and operation of the cooling tower. Field installation
is always required for piping inlets and piping outlets. The fan guard on
larger models an some optional accessories, such as valves, handrails,
ladders and safety cages may also require field installation. If installation
details are not covered in the Field Installation Manual a separate instal-
lation drawing for each purchased option is included in the document
package. If you have purchased an option and can’t find the appropriate
installation drawing, contact your local Marley sales representative before
proceeding.
For complete parts and service assistance, contact the Marley sales rep-
resentative in your area. If you need help locating the office nearest you,
please phone 800 462 7539 or check the internet at spxcooling.com.
30
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7401 WEST 129 STREET OVERLAND PARK, KANSAS 66213 UNITED STATES 913 664 7400 [email protected] spxcooling.com
In the interest of technological progress, all products are subject to design and/or material change without notice.
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©2008 SPX Cooling Technologies, Inc. Printed in USA
Manual 98-1514E
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