SPX Cooling Technologies Marley Series NC and NC Modular Steel Double-Flow User Manual

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SPX Cooling Technologies Marley Series NC and NC Modular Steel Double-Flow User Manual | Manualzz
 MANUAN
Series NC and NC Modular Steel
Double-Flow
Cooling Towers
OM-NC1-A
Installation, Operation,
and
Maintenance Instructions
August, 1991 | Manual 92-1326
The Marley Cooling Tower Company
5800 Foxridge Drive * P.O. Box 2912 *« Mission, Kansas 66201
Phone: (913) 362-1818 FAX: (913) 362-3610
WARNING
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.
Series NC and NC Modular
Cooling Towers
Table of Contents
Tower LOCAtION ore rcaneneno ne cecere ne ereneecreerereconeecenee page 3
Tower Shipment ..................-.....0mereeeee ene ere Decana reee ere cerrar rereree ner. page 3
Receiving TOWET ….…......….…….….rcresessereressncerrassanercaraneeaerene senc crea cree rentes cree page 4
Hoisting Tower .....................emrceco een Deere ree eran cer eeeee reee een. page 4
Tower Installation ..................erecererreerreceno ocean enana nen enecenenenenereneecencecerenene—e page 4
Tower Start-UDP ...................eeereec0eeoo oro ie eran De erecac coreo nrecereorenerrnene reee. page 5
Tower Operation ......................erermecereneiee ne ere e ercer erre reee cernes page 6
Water Treatment and BloWdown ....................e.eemeirerer e e DI eas page 7
Motor Re-Lubrication InstrUCtIONS ..…..….......….….ssenenererenererrarserr rca rec cevee page 8
Schedule of Tower Maintenance .……..…......….…rrresssesenessssansassssesse nana 00000 page 9
Seasonal Shutdown InstrUCtiONS .….…….......….…....…..crereceseseseressssrssaren era en cencecence page 9
Prolonged Shutdown .................e.e.emmerecereier ec ene e reee ene page 9
Marley SErViCES .…………………rrrrceriencenensesnnnnennsantenenentennennnnnÜennnnnnnnnnnn page 10
Tower Trouble Tips (oor eee encres pages 10 & 11
Additional Installation and Maintenance Information .........................eom.... page 12
The following defined terms are used throughout this manual to bring attention to the presence of hazards oí
various risk levels, or to important information concerning the life of the product.
DANGER indicates presence of a hazard which will CAUTION indicates presence of a hazard which will or
| cause severe personal injury, death or sub- can cause minor personal injury or property
stantial property damage if ignored. damage if ignored.
cause severe personal injury, death or sub- tion, operation or maintenance which are
stantial property damage if ignored. important but not related to personal injury
hazards.
WARNING indicates presence of a hazard which can NOTICE indicates special instructions on installa-
—2
Marley Series NC and NC Modular
Cooling Towers
Installation, Operation, and Maintenance Instructions
The Marley Series NC cooling tower purchased for this
installation represents 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, Geareducers®, couplings, drive shafts, float
valves, etc. — are intended to assure that the tower serves
you properly 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 mainte-
nance of this tower, and you don’t find the answers in this
manual, please contact your Marley sales engineer. When
writing for information, or when ordering parts, please
mention tower serial number shown on the nameplate.
Safety First
The location and orientation of the cooling tower can affect
the safety of those responsible for installing, operating or
maintaining the tower. However, since Marley does not
determine the location or orientation of the tower, we can
not be responsible for addressing those safety issues that
are affected by the tower’s location or orientation.
The following safety issues should be considered
by those responsible for designing the tower
installation.
access to and from the fan deck
access to and from maintenance access doors
potential access problems due to obstructions
surrounding the tower
the possible need for handrails around the fan
deck
the possible need for for ladders (either portable
or permanent to gain access to the fan deck or
maintenance access doors)
lock-out of mechanical equipment
the possible need for safety cages around ladders
These are only some of the safety issues that may
arise in the design process. Marley strongly
recommends that you consult a safety engineer
to be sure that all safety considerations have
been addressed.
Several options are available that may assist you in ad-
dressing some of these personnel safety concerns, including:
* a handrail system around the perimeter of the fan deck
with either one or two ladders for access to the deck
ladder extensions (used where the base of the tower is
elevated)
safety cages for fan deck ladders
external lube lines
fan cylinder extensions
* flow control/balancing valves
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 available space and the
intended configuration of the tower, please contact your
Marley sales engineer 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.
CAUTION
The cooling tower must be located at such dis-
tance and direction to avoid the possibility of
contaminated tower discharge air being drawn
into building fresh air intake ducts. The pur-
chaser should obtain the services of a Licensed
Professional Engineer or Registered Architect to
certify that the location of the tower is in compli-
ance with applicable air pollution, fire, and clean
air codes.
Tower Shipment
Unless otherwise specified, Series NC towers ship by truck
(on flat bed trailers), which lets you receive, hoist, and
install the tower in one continuous operation. Single cell
towers ship on one truck. Multi-cell 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 shipment for evidence of damage in transit. If
damage 1s apparent, note the freight bill accordingly. This
will support your future recovery claim.
Find and remove the installation instruction drawings,
located in a container shipped in the cold water basin. The
drawings will be valuable for future reference.
Hoisting Tower
Models NC800 and NC900 consist of two modules per cell.
The upper module includes heavy duty hoisting clips at the
top of the module. The hoisting clips for the lower module
are located near its bottom. All other models ship in a
single module, with hoisting clips located on the cased faces
of the tower. A hoisting instructions decal is located on the
casing, near the tower centerline. Remove tower from the
carrier and hoist into place according to the instructions on
the decals.
If hoisting and installation are to take place simultaneously,
hoist the bottom section first. (This is the section including
the cold water basin.)
WARNING
Hoisting clips are provided for ease of unload-
ing and positioning tower. For overhead lifts or
where additional safety is required, safety slings
should also be placed under the tower.
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 instruc-
tions shipped with the tower will govern.
. Place tower (or bottom section) on your prepared
supports, aligning anchor bolt holes with those in your
supporting steel. (Make sure that the orientation
agrees with your intended piping arrangement.) Attach
section to supporting steel with four 1/2” diameter bolts
(5/8” diameter bolts for models NC800 and NC900).
. Unbolt and remove any wooden shipping skids from top
section. Place top section on top peripheral bearing
surface of bottom section, aligning mating holes as it is
set in place. (Make sure that the orientation of the top
section agrees with your intended piping arrangement.
Sections are 180° reversible with respect to each other.)
Attach top section to bottom section with fasteners
provided — according to drawing instructions.
If tower purchased is one cell only, ignore steps 4
through 8.
. Unbolt endplate from the basin of the cell just installed.
(It is located in the basin side.) In its place, attach
basin equalizer flume collar according to drawing
instructions.
. Unbolt endplate from the basin of the 2nd tower and set
2nd tower (or bottom section of 2nd cell) in place. Align
anchor bolt holes and flume openings in basin sides.
. Attach flume collar to 2nd cell basin and install flume
according to drawing instructions.
NOTE
It is important that the cells be firmly anchored
before the flume is affixed to the 2nd cell.
Endplates must be removed prior to setting tow-
ers. However, collars and flumes may be in-
stalled after towers are set in place and an-
chored.
. Repeat steps #2 and #3 for 2nd top section on models
NC800 and NC900.
8.
9.
10.
11.
12.
Repeat steps 4 through 7 for any remaining cells.
Attach your cold water supply piping to the cold water
basin suction connection in accordance with drawing
instructions.
NOTE
Do not support your pipe from the tower or
outflow connection — support it externally.
Normally, one of the following three outflow arrange-
ments is provided:
Side suction connection: This is a factory-installed,
galvanized pipe nipple (6” diameter or larger, as
appropriate) extending horizontally from the side 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. Cold galvanizing is
suggested, applied according to the manufacturer’s
instructions.
Bottom outlet connection: This is a factory-installed
screened circular opening in the cold water basin floor
of one or more cells. Attachment requires that your
pipe be equipped with a 125# ANSI B16.1 flange.
Depressed sump connection: Unless otherwise
specified, sumps are manufactured of heavy duty GRP
(glass reinforced polyester) construction. Because of
their size, they are attached upside down in the basin to
prevent damage in shipment. They must be inserted
into the square opening prepared 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 accept a 125# ANSI B16.1 flange
connection.
Attach make-up water supply piping to appropriately-
sized float valve connection located in cold water basin
side wall. If you wish to conduct overflow and drain
water to a remote discharge point, make those connec-
tions at this time also.
Attach your warm water return piping (riser) to the
inlet connections of the tower. Removing the inlet
flume assemblies will make access to the inlet fasteners
much easier.
NOTE
Do not support your pipe from the tower — sup-
port it externally.
NOTE
Efficient tower operation requires uniform flow
to all distribution basins. You can address this
need by installing regulator valves in your riser
piping to each basin or by equipping your tower
with Marley HC flow control valves.
Wire motor in accordance with wiring diagram.
WARNING
For maintenance/safety purposes, provide a lock-
out type disconnect switch located such that it is
visible from the mechanical equipment region of
the tower.
loss of oil.) If oil is required, fill Geareducer to the
proper level. Check oil level at Geareducer view port or
dipstick (standpipe located on fan deck, if so equipped)
In addition to this disconnect switch, the motor should
be wired to main power supply through short circuit
protection, and a magnetic starter with overload
protection. to confirm that the proper level is indicated.
2. Spin the fan manually to assure that all fan blades
Tower Start-Up properly clear the inside of the fan cylinder. Observe
the action of the coupling (or drive shaft couplings) to be
sure that the motor and Geareducer are properly
Water System:
1. 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.
. Fill the water system to an approximate depth of 2-1/8”
in the area of the cold water basin under the fill (3-1/8”
depth in models NC800 and NC900). This is the
recommended operating water level. Adjust the float
valve so that it is essentially closed at that level.
Continue filling the system until the water reaches a
level approximately 1/8” below the lip of the overflow.
NOTE
If tower is equipped with a standard side-suc-
tion connection, vent any accumulated air from
the top of the suction hood by removing one or
both tap screws provided at that location. Re-
place these tap screws when venting is complete.
. Completely open all hot water flow control valves. Start
your pump(s). Observe system operation. Since the
water system external to the tower will have been filled
only to the level achieved in the cold water basin, a
certain amount of “pump-down” of the basin water level
will occur before water completes the circuit and begins
to fall from the fill. The amount of initial pump-down
may be insufficient to cause the float valve to open.
However, you can check its operation by pressing down
on the operating lever to which the stem of the float
valve is attached.
. After reaching design water flow rate, adjust the valves
to equalize hot water depth in the distribution basins.
Each basin should have from 2.8 to 5.4 inch water
depth, with uniform depth from basin to basin. Fix
Uniform distribution depth of 2.8 to 5.4 inches is
essential to efficient tower operation. Contact your
Marley sales engineer if you are considering a change in
circulating water flow rate that would prevent opera-
tion within these limits.
. Continue pump operation for about 15 minutes, after
which it is recommended that the water system be
drained, flushed, and refilled.
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.
. Check oil level in accordance with the operating
instructions for the Geareducer. (Although Geareducer
was filled to the proper level at the factory, tipping
during shipment and hoisting may have caused some
aligned. If necessary, correct the alignment in accor-
dance with the included manual.
3. Install top fan ring and fan guard according to the
installation drawing shipped with the tower. Models
NC100 through NC300 include a single-piece fan guard.
Models NC400 through NC900 include a two-piece fan
guard which requires the use of a fan guard support
and splice hardware.
Be sure to bend the support (raising the center of the
guard) in order to align with holes in the fan cylinder.
Do not force the fan cylinder out.
It is essential that the fan cylinder and fan guard
be installed in accordance with the installation
drawing shipped with the tower.
WARNING
Improper installation of the fan cylinder and
fan guard will destroy the structural integrity of
the fan guard. Failure of the fan guard could
allow operating or maintenance personnel to
fall in to the rotating fan.
4. Momentarily energize (“bump”) the motor and observe
rotation of the fan. The fan should rotate in a counter-
clockwise direction when viewed from below. If rotation
1s backwards, shut off the fan and reverse two of the
three primary leads supplying power to the motor.
NOTE
If tower is equipped with a two-speed motor,
check for proper rotation at both speeds. Check
also to see that starter is equipped with a 20
second time delay which prevents direct switch-
ing from high speed to low speed. This delay will
allow the fan to slow down, and will prevent
abnormal stress from being applied to the me-
chanical equipment and the electrical circuit
components.
5. Run the motor and observe the operation of the me-
chanical equipment. Operation should be stable, and
there should be no evidence of oil leakage.
NOTE
If the water supply system is not being operated
—orifthere is no heat load on the system — motor
amps read at this time may indicate an appar-
ent overload of as much as 10-20%. This is
because of the increased density of unheated air
flowing through the fan. Determination of an
accurate motor load should await the applica-
tion of the design heat load.
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
The cooling tower establishes only the cold water
temperature attainable under any operating circum-
stance.
. 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 tempera-
tures. However, the cold water temperature will not
vary to the same extent as the wet-bulb. For example, a
20°F reduction in wet-bulb may result in only a 15°F
reduction in cold water temperature.
. Water flow rate: Increasing the water flow rate
(GPM) will cause 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), GPM
reductions also cause an increase in the incoming hot
water temperature. Use care to prevent the hot water
from exceeding 125°F, in 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 tempera-
ture to rise. When the water temperature then becomes
too warm for your process, the motor can be restarted.
NOTE
When operating in this mode care must be taken
not to exceed a total acceleration time of 30
seconds per hour.
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. Considering the normal fan and motor
sizes utilized on Series NC towers, anticipate that
approximately 4 to 5 starts per hour are allowable.
If your tower is equipped with a two-speed motor, you
will enjoy greater opportunity for temperature control.
When the water temperature becomes too cold, switch-
ing the fan to half-speed will cause the cold water
temperature to rise — stabilizing at a temperature some
5-15 degrees higher (depending upon a combination of
all operating factors). With a further reduction in
water temperature, the fan may be cycled alternately
from half-speed to off — 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 Technical Report #H-001-A (“Cooling Tower
Energy and its Management”) available from your
Marley sales engineer.
Wintertime operation:
During operation in sub-freezing weather, the opportunity
exists for ice to form in the colder regions of the tower. Your
primary concern is to prevent the formation of destructive ice
on the cooling tower fill. Your understanding of cold
weather operation will be enhanced if you read Technical
Report #H-003 (“Operating Cooling Towers in Freezing
Weather”), augmented by the following guidelines:
1. Do not allow the tower's leaving water temperature to
drop below a minimum allowable level — (about 40°F) —
established as follows:
During the coldest days of the first winter of operation,
observe whether any ice is forming on the louver face,
particularly near the bottom part of the louver face. If
hard ice is present on the 1- uvers, 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 maximum heat load, it should be
safe for all operating conditions. However, if estab-
lished at reduced load, increased heat loads may re-
introduce the potential for icing.
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, the limiting temperature established
applies to the water temperature of the cell or cells
operating at the highest fan speed — not necessarily the
net cold water temperature produced by the entire tower.
2. As cold air enters the louvers, it causes the falling
water to be drawn inward toward the center of the
tower. Thus, under fan operation, the louvers and
lower periphery of the tower structure remain partly
dry, seeing only random splashing from within the
tower — plus normal atmospheric moisture from the
entering air. Such lightly wetted areas are most subject
to freezing.
Although ice is unlikely to cause structural damage, it
may build up sufficiently to restrict the free flow of air
through the louvers. This will have the effect of
reducing the tower’s thermal performance efficiency.
When excessive ice forms on the louvers, stop the fan
for a few minutes. With the fan off, the increase in the
water temperature and the action of the cascading
water will reduce the ice build-up on the louvers. In
extreme cases, brief fan reversal will also help to
remove ice. Reverse fan operation should not exceed 15
to 20 minutes.
Intermittent wintertime operation:
If periods of shutdown (nights, weekends, etc.) occur during
freezing weather, measures must be taken to prevent the
water in the cold water basin —- and all exposed pipework —
from freezing. Several methods are used to combat this,
including automatic basin heater systems available from
Marley.
NOTE
Unless some means of freeze prevention is incor-
porated into your system, the tower basin and
exposed pipework should be drained at the be-
ginning of each wintertime shutdown period.
It is recommended that you discuss your freeze prevention
options with your local Marley sales engineer.
Water Treatment and Blowdown
Maintaining water quality:
The steel used in Series NC towers has been galvanized
with a heavy zinc coating averaging 1.9 mils in thickness.
Other materials used (PVC fill, drift eliminators, and
louvers; aluminum fans; cast iron Geareducer; etc.) are
selected to offer maximum service life in a “normal” cooling
tower environment, defined as follows:
* Circulating water with a pH between 6 and 8; a chloride
content (as NaCl) below 750 ppm; a sulfate content
(SO,) below 1200 ppm; a sodium bicarbonate content
(NaHCO,) below 200 ppm; a maximum inlet water
temperature not to exceed 125°F; no significant con-
tamination with unusual chemicals or foreign sub-
stances; and adequate water treatment to minimize
scaling.
® Chlorine (if used) shall be added intermittently, with a
free residual not to exceed 1 ppm — maintained for short
periods.
* An atmosphere surrounding the tower no worse than
“moderate industrial”, where rainfall and fog are no
more than slightly acid, and they do not contain
significant chlorides or hydrogen sulfide (H,S).
Since the structure of your cooling tower consists primarily
of galvanized steel, your water treatment program must be
compatible with zinc. In working with your water treat-
ment supplier, it is important that you recognize the
potential effects on zinc of the specific treatment program
you choose.
Cooling tower cleaning:
WARNING
Anyevaporative-type cooling tower must be thor-
oughly 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 per-
sonal protective equipment. Do NOT attempt
any service unless the fan motor is locked out.
Operators of evaporative cooling equipment, such as water
cooling towers, should follow maintenance programs which
will reduce to an absolute minimum the opportunity for
bacteriological contamination. Public Health Service
officials have recommended that “good housekeeping”
procedures be followed, such as: regular inspections for
concentrations of dirt, scale, and algae; periodic flushing
and cleaning; and the following of a complete water treat-
ment program including biocidal treatment.
The visual inspection should take place at least once a week
during the operating season. The periodic flushing and
cleaning should be done before and after each cooling
season, but in any event at least twice a year. The 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. À reliable
water treatment program should be installed and main-
tained. Filtration devices may be employed to reduce the
suspended solids concentrations, thus increasing the
effectiveness of the water treatment program.
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 make-up 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 concentrations.
This stabilization of contaminant concentrations is usually
accomplished by blowdown, which is the constant discharge
of a portion of the circulating water to waste. As a rule,
acceptable levels on which to base a treatment schedule will
be in the range of 2-4 concentrations. The following table
gives approximate rates of blowdown (percent of total water
flow rate constantly wasted) to achieve those concentrations
at various cooling ranges*:
Blowdown Rate
Cooling Two Four
Range (°F) Concentrations Concentrations
10 0.7% 0.17%
15 1.1% 0.30%
20 1.5% 0.43%
* (“Range” = Difference between hot water temperature
entering the tower & cold water temperature leaving
the tower.)
NOTE
When water treatment chemicals are added,
they should not be introduced into the circulat-
ing water system via the cold water basin of the
cooling tower. Water velocities are lowest at
that point, which results in inadequate mixing.
Schedule of Tower Maintenance
Some maintenance procedures may require maintenance
personnel to enter the tower. Each cased face of the tower
contains a 38” wide by 35” high door for access to the
interior of the tower.
Motor Re-Lubrication Instructions
(for towers with motor located outside the plenum)
— MOTOR
GREASE FILL
— CASING
DRIVESHAFT GUARD
DRIVESHAFT
- GREASE RELIEF
PLUG
TAP SCREW
1/4 X 3/4
WARNING | 3. Insert grease fittings in grease fill openings and add
Open and lock out disconnect switch to make grease until grease is forced out through relief openings
certain motor cannot be started. 4. Replace fill plugs and operate mechanical equipment 30
minutes to one hour to purge excess grease at grease
. Remove guard and cover plates as shown above. Oppo- relief opening.
site end motor bearing is accessible from outside the
tower. 5. Reinstall grease relief plugs and reinstall guard and
. Remove grease fill and relief plugs at both shaft exten- cover plates.
sion end and opposite end bearings and remove hard- 6. Resume normal tower operation.
ened grease, using clean wire.
The optional fan deck ladder is designed and intended solely
to allow pesonnel to gain access to the fan deck. The fan
deck ladder should not be used when entering tor exiting
the maintenance access doors located on the cased face of
the tower.
WARNING
The purchaser or owner is responsible for pro-
viding a safe method for entering or exiting the
access door. Use of the fan deck ladder to enter
or exit the access doors may result in a fall.
Provision for safe access and egress through the access
doors is to be provided by purchaser or their agent.
Included with this instruction packet are separate Service
Manuals on each major operating component of the tower,
and it is recommended that you read them thoroughly.
Where discrepancies may exist, the separate Service Manuals
will take precedence.
The following is recommended as a minimum routine of
scheduled maintenance:
Always shut off electrical power to the tower fan
motor prior to performing any inspections that
may involve physical contact with the mechani-
cal 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.
Daily: Observe, touch, and listen to the tower for a few
moments each day. Become accustomed to its normal
appearance, sound, and level of vibration. Abnormal
aspects relating to the rotating equipment should be
considered reason to shut down the tower until the problem
can be located and corrected.
Weekly: Observe operation of the motor, coupling (or drive
shaft), Geareducer and fan. Become familiar with the
normal operating temperature of the motor, as well as the
sight and sound of all components as a whole.
Shut off the fan for a few minutes, check the level of oil in
the Geareducer. Add oil as necessary. Check system for
leaks if the amount of oil required appears unusual. (If oil
is added at the external fill port, allow adequate time for the
level to stabilize before reading final level.)
Inspect louvers, and remove any debris which may have
accumulated. Observe operation of the float valve. Depress
the operating lever to make sure that the valve is operating
freely. Inspect the suction screen for plugging. Remove any
debris that may have accumulated.
Check for any build-up of silt on the floor of the cold water
basin. Mentally note the amount, if any, so future inspec-
tions will enable you to determine the rate at which it is
forming.
Monthly: Check Geareducer oil sample for presence of
water and/or sludge. Make sure vents are open. (See
Geareducer Manual.)
Semi-Annually: Drain Geareducer and refill with fresh
oil, as outlined in the Geareducer Manual. If sludge is
present in the oil removed, flush Geareducer before refilling.
—9—
Re-lubricate motor according to the manufacturer’s instruc-
tions. See page 8 for towers with the motor located outside
the plenum.
Check to see that all bolts are tight in the fan and mechani-
cal equipment region, including the fan cylinder and fan
guard. (Use torque settings prescribed on the fan name-
plate.)
Visually inspect the drift eliminators. Remove any accumu-
lated debris or scale.
If basin silt level is significant, drain the basin and clean it
out. Refer to “Cooling Tower Cleaning” section above.
Annually: Inspect the tower thoroughly, making maximum
use of instructions given in the separate service manuals.
Check structural bolted connections and tighten as re-
quired. Make preventive maintenance repairs as necessary.
Seasonal Shutdown Instructions
Drain the tower basin(s) and all exposed piping. Leave the
basin drains open.
During shutdown, clean the tower and make any necessary
repairs. Pay particular attention to mechanical equipment
supports and coupling (or drive shafts).
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, consider that the galvanizing has remained
effective. Unless there is 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 structural bolted connections
and tighten as required.
Geareducers:
1. At shutdown, operate Geareducer until oil is warm,
then drain and refill in accordance with the Geareducer
service manual.
Each month during shutdown, drain any water that
may have condensed inside the Geareducer and lubrica-
tion system. Check oil level and add oil if necessary.
Operate Geareducer to re-coat all interior surfaces with
oil (see “electric motors” below).
Check Geareducer anchor bolts and tighten as required.
At next season start-up, operate Geareducer until oil 1s
warm; drain and refill.
Fans: Check fan assembly bolting and tighten as required.
(Use torque settings prescribed on the fan nameplate.)
Electric motors: Clean and lubricate motor at close of
recommendations.) Check motor anchor bolts and tighten
as required. (See Page 8 for towers with motor located
outside the plenum.)
I WARNING
Do not start motor before determining that there
will be no interference with free rotation of the
fan drive.
The motor should be operated for three hours at least once a
month. This serves to dry out windings and re-lubricate
bearing surfaces. (Refer to Marley electric motor service
manual.)
At start of new operating season, make sure bearings are
adequately lubricated before returning motor to service.
Prolonged Shutdown
If shutdown period is longer than seasonal, contact your
Marley sales engineer for additional information.
Marley Services
Marley's interest in your Series NC cooling tower does not
end with the sale. Having conceived, designed, and manu-
factured the most reliable and longest-lasting cooling tower
of its class, we want to make sure that you gain the maxi-
mum possible benefit from its purchase.
Therefore, the following services are available which are
intended to: assure the maximum possible service life
under your operating conditions; tailor the operating
characteristics to your specific needs; and maintain consis-
tently optimum thermal performance capability. They are
available by contacting your Marley Cooling Tower Com-
pany sales engineer.
Replacement parts: With the exception of the motor,
every component of your tower is designed and manufac-
tured by The Marley Cooling Tower Company. We do this
because commercially available components have not proved
capable of withstanding the harsh environment of a cooling
tower — nor do they contribute their share to the thermal
capability and operating characteristics intended.
A complete stock of all parts and components is maintained
at 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 their 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
Marley for regularly scheduled visits — for the purpose of
inspecting and reporting your tower’s condition — to make
recommendations intended to prevent emergencies — 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, Marley recognizes that the unusual
manner in which a cooling tower performs its function — as
well as the unique forces which act upon it — may be
considerations which occasionally require the services of an
expert technician.
Tower Trouble Tips
Trouble Cause
Remedy
Motor will not start Power not available at motor terminals
1. Check power at starter. Correct any bad connections between
the control apparatus and the motor.
2. Check starter contacts and control circuit. Reset overloads,
close contacts, reset tripped switches or replace failed control
switches.
3. If power is not on all leads at starter make sure overload and
short circuit devices are in proper condition.
Wrong connections
Check motor and control connections against wiring diagrams.
Low voltage
Check nameplate voltage against power supply. Check voltage at
motor terminals.
Open circuit in motor winding
| Check stator windings for open circuits.
Motor or fan drive stuck
Disconnect motor from load and check motor and Geareducer for
cause of problem.
Rotor defective
Look for broken bars and rings.
Unusual motor noise Motor running single-phase
Stop motor and attempt to start it. Motor will not start if single-
phased. Check wiring, controls and motor.
Motor leads connected incorrectly
Check motor connections against wiring diagram on motor.
Bad bearings
Check lubrication. Replace bad bearings.
Electrical unbalance
Check voltage and currents of all three lines. Correct if required.
Air gap not uniform
Check and correct bracket fits or bearing.
Rotor unbalance
Rebalance.
Cooling fan hitting end bell guard
Reinstall or replace fan.
Fan noise Blade rubbing inside of fan cylinder
Adjust cylinder to provide blade tip clearance.
Loose bolts in blade clamps
Check and tighten if necessary. Check fan blade pitch. Refer to
Fan Service Manual.
—10-
Tower Trouble Tips
Trouble
Cause
Remedy
Scale or foreign sub-
stance in water system
Lack of or insufficient bleed-off
See “Water Treatment” section of this manual.
Water treatment
Consult competent water treating specialist. See “Water
Treatment” section of this manual.
Motor does not come up
to speed
Voltage too low at motor terminals because of
line drop
Check transformer and setting of taps. Use higher voltage on
transformer terminals or reduce loads. Increase wire size or
reduce inertia.
Broken rotor bars
Look for cracks near the rings. A new rotor may be required.
Have motor service center check motor.
Wrong rotation (Motor)
Wrong sequence of phases
Switch any two of the three motor leads.
Excessive water drift Faulty drift elimination 1. See if all louvers and eliminators are in place and clean.
2. Check to see that nozzles are in place and clean of debris.
Overpumping Reduce water flow rate to tower to design conditions.
Cold water too warm (See | Overpumping Reduce water flow rate to tower to design conditions.
“Tower Operation”)
Not enough air
Check motor current and voltage to be sure of correct contract
horsepower. Clean louvers, fill and eliminators.
Unusual fan drive
vibration
Loose bolts and cap screw
Tighten all bolts and cap screws on all mechanical equipment
and supports.
Worn couplings or misalignment
—0r—
Unbalanced drive shaft or worn couplings
(Optional equipment)
Make sure motor and Geareducer shafts are in proper alignment
and “match marks” properly matched. Repair or replace worn
couplings. Rebalance drive shaft by adding or removing weights
from balancing cap screws. See Drive Shaft Service Manual.
Unbalanced fan
Be sure blades are properly positioned in correct sockets. (See
match numbers.) Make certain all blades are as far from center
of hub as safety devices permit. All blades must be pitched the
same. See Fan Service Manual. Clean off deposit build-up on
blades.
Worn Geareducer bearings
Check fan and pinion shaft endplay. Replace bearings as
necessary.
Unbalanced motor
Disconnect load and operate motor. If motor still vibrates,
rebalance rotor.
Bent Geareducer shaft
Check fan and pinion shafts with dial indicator. Replace if
necessary.
Motor runs hot
Motor overload, wrong voltage or unbalanced
voltage
Check voltage and current of all three lines against nameplate
values.
Wrong motor RPM
Check nameplate against power supply. Check RPM of motor
and gear ratio.
Bearings overgreased
Remove grease reliefs. Run motor up to speed to purge excessive
grease.
Wrong lubricant in bearings
Change to proper lubricant. See motor manufacturer’s instruc-
tions.
One phase open
Stop motor and attempt to start it. Motor will not start if single-
phased. Check wiring, controls and motor.
Poor ventilation
Clean motor and check ventilation openings. Allow ample
ventilation around motor.
Winding fault
Check with Ohmmeter.
Bent motor shaft
Straighten or replace shaft.
Insufficient grease
Remove plugs and regrease bearings.
Too frequent starting
Limit cumulative starting time to a total of 30 seconds each hour.
Deterioration of or foreign material in grease
Flush bearings and re-lubricate.
Bearings damaged
Replace bearings.
Incorrect fan blade pitch Measure actual fan pitch and compare to that recommended.
Correct, if necessary. See Fan Service Manual.
Geareducer noise 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 bearings.
Gears Correct tooth engagement. Replace badly worn gears. Replace
gears with imperfect tooth spacing or form.
—11—
Increased load requirements: Series NC 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 replace-
ment or addition of production equipment — and still retain
continuity with respect to your cooling tower system.
Tower rebuilding: Marley routinely rebuilds and up-
grades cooling towers of a/l materials and makes. If your
tower ever reaches the limit of its service life, we recom-
mend that you investigate the cost of rebuilding before you
routinely order a new replacement tower.
ADDITIONAL INSTALLATION AND MAINTENANCE INFORMATION
Each NC tower includes a document package containing general orientation drawings and drawings required to accomplish
field installation. These drawings contain important information relating to safe installation 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. A separate installation
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 application engineer before proceeding.
Your Marley application engineer also provides several sets of a separate packet of pertinent operating and maintenance
manuals. The manuals vary somewhat depending on the tower model purchased. Your final operating and maintenance
package should include the following Marley manuals:
MobeLs NC100
Series NC & NC Modular Installation, Operation and
Maintenance Instructions ........................eceeeos OM-NC-1
Electric Basin Heater Installation, Operation and Mainte-
nance Instructions ................e=2..e.e..m0ccermeee. OM-BHSC
Downtime Instruction Manual .......................emve.... DM-MDT
Electric Motor Service Manual .......................... SM-MOTOR
Marley Type H3 Fan Service Manual ......... SM-H3A-55-168
Marley Series 10T Geareducer® Service Manual. SM-10
Marley Series 10T Geareducer Parts List ................... PL-10
Marley Series 220 Close Coupling Service Manual
perecanecasecareneroorenenanaccacnaee ere ro recaer eereanereenanaes SM-CC-M220
Marley Series Q1 Driveshaft Service Manual ........... SM-Q1
Marley HC Flow Control Valve Parts List ........ PL-CV-4-6-8
Marley M-1 Vibration Limit Switch (SPDT) General Details
Drawing covers 67-3510
MobeLs NC200 - NC900
Series NC & NC Modular Installation, Operation and
Maintenance Instructions eee OM-NC-1
Electric Basin Heater Installation, Operation and Mainte-
nance Instructions .…….......erssrecrrrnncensensers OM-BHSC
Downtime Instruction Manual ….…….......…resere DM-MDT
Electric Motor Service Manual .......................... SM-MOTOR
Marley Type H3 Fan Service Manual ......... SM-H3A-55-168
Marley Series 20T & Series 22.2 Geareducer Service
Manual .................e.eerercecceceoe recen eee ea eee SM-20-22
Marley Series 20T Geareducer Parts List ................... PL-20
Marley Series 22.2 Geareducer Parts List ................ PL-22.2
Marley Series 220 Close Coupling Service Manual
eencenenenoreneoeareaen ene aaracacerenearra ne acorereceareoe neos SM-CC-M220
Marley Series 6Q & Series 175 Driveshaft Service
Manual ................esecerciccccreconiroon entoces SM-6Q & 175
Marley HC Flow Control Valve Parts List ........ PL-CV-4-6-8
Marley M-1 Vibration Limit Switch (SPDT) General Details
Drawing ...............re....ecceomerecrcocciore eoccceceroe nee enenee 67-3510
Since these manual packets include information on several of the more popular equipment options, you may find that you
have manuals for options not included with your tower.
In addition to these specific manuals, Marley publishes numerous technical reports including more detailed information on a
variety of cooling tower operation and service topics. Your Marley application engineer will be happy to give you copies of
these reports at no charge. Just call your local office and ask for the Cooling Tower Information Index series.
For complete parts and service assistance, contact the Marley sales or representative office in your area. If you need help
locating the office for you to call, please phone toll-free 1-800-322-6200.
THE MARLEY COOLING TOWER COMPANY
—12-

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