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6
After 24 hours of operation
under thermal load, perform the
following services:
9
Check the tower for any
unusual noise or vibrations.
9
Check the operating water
level in the hot and cold water
basins.
9
Adjust the make-up valve if
necessary.
9
Check the belt tension and
readjust if necessary.
9
Inspect the spray nozzles and
heat transfer section.
• Adjust the valve (supplied by others) in the tower bleed line to achieve the desired
bleed rate by closing or opening the valve.
• Inspect the nozzles and heat transfer section as described in “Water Distribution
System” on
page 19 (Figure 6)
.
• Execute one of the following biocide treatment programs while operating the
circulating pump and prior to operating the unit fans:
–
Resume treatment with the biocide that was used prior to shutdown. Operate the
pump only while maintaining the maximum recommended biocide residual for a
sufficient duration (residual and time will vary with the biocide) as recommended
by the water treatment supplier. Start the fan only after this treatment period is
completed.
–
Check the pH of the circulating water and, if necessary, adjust it to 7.0 - 7.6 pH.
Then, running the pump only, treat the system with sodium hypochlorite to maintain
a level of 4 to 5 mg/l (ppm) free chlorine (as Cl
2
) over a six hour period. Test kits for
measuring the free residual of chlorine are commercially available. Start the fan only
after this treatment period is completed.
• For units with the optional gear drive system, see
page 13
for initial start-up.
• For initial start-up, briefly energize the fan motor(s) and note the direction of rotation.
The fan should rotate in the direction indicated by the arrow on the fan cowl.
• Run the fan in manual mode for several minutes to check for any unusual noise or
vibrations.
• For the BALTIGUARD™ Fan System, BALTIGUARD PLUS™ Fan System or 2-speed
motors: check that the starter incorporates a 15 second time delay when switching
from high to low speed.
• Check the operation of the vibration cutout switch (see
page 32
).
• Once the cooling tower is operating, check the current and voltage of all three phases
(legs) of the fan motor with a heat load on the tower under warm ambient conditions.
The current must not exceed the motor nameplate rating.
• For units with VFDs, see
page 35
.
• For units with the optional Electric Water Level Control, see
page 20
.
Extended Shutdown
Perform the following services whenever the unit is shutdown in excess of three days:
• If the unit is mounted on vibration isolators or isolation rails (by others), refer to the
manufacturer’s guidelines before loading/unloading weight from the unit.
• Disconnect, lock-out, and tag-out all fans and pumps.
• Close the shut-off valve in the make-up water line (supplied by others) and drain cold
water basin and all exposed water piping. Heat trace and insulate all exposed piping.
• To minimize the risk of biological contamination during shutdown, it is recommended
the entire system be drained.
• Clean all debris, such as leaves and dirt, from the interior and exterior of the unit,
including the louvers or the optional combined inlet shields.
• Clean and flush the cold water basin with the basin strainer in place.
• Leave the cold water basin drain open so rain and melting snow will drain from the
unit.
ATTENTION:
Check to ensure the
controls for the fan motor are set
to allow a maximum of six on-off
cycles per hour to prevent motor
overload.
DANGER:
Do not perform any service
on or near the fans, motors, and
drives, or inside the unit without
first ensuring that the fans and
pumps are disconnected, locked
out, and tagged out.