BAC PCT Series, Руководство по эксплуатации и техническому обслуживанию

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17
W W W . B A L T I M O R E A I R C O I L . C O M . A U
M A R 1 0 8 - 2
CAUTION: Do not use steam or
high pressure water to clean PVC
eliminators or materials other
than steel.
Detailed Component
Maintenance Procedures
Louvres and Eliminators
Water Distribution and Heat Transfer Section
NOTE: If the unit has been
ordered with the optional
electric water level control
package or is intended for
remote sump application, a
mechanical water make-up
valve will not be provided.
Water Level Control
There are two types of water level controls used on BAC cooling towers:
• Mechanical make-up valve assembly
• Optional electric water level control package
Mechanical Make-up Valve Assembly
A float-operated mechanical water make-up assembly is furnished
as standard equipment on the cooling tower. The standard make-up
assembly consists of a corrosion resistant make-up valve connected to
a float arm assembly actuated by a polystyrene-filled plastic float. The
float is mounted on an all-thread rod held in place by wing nuts. The
cold water basin operating water level can be adjusted by repositioning
the float and all-thread rod using the wing nuts provided.
• Inspect the make-up valve assembly monthly and adjust if necessary.
• Inspect the valve annually for leakage. Replace the valve seat if
necessary.
• Maintain the make-up water supply pressure between 100 and 350
kPa for proper operation. BAC recommends a surge protector
(provided by others) for pressures over 350 kPa.
• Set the initial basin water level by adjusting the wing nuts so
that the make-up valve is completely closed when the water level
in the cold water basin is at the operating level.
• With the design thermal load and the average water pressure
(100 to 350 kPa) at the valve, the above setting will produce
operating water levels as stated in
Table 1 on Page 9 .
• If the thermal load is less than the design load at the time of
unit start-up, the procedure may produce operating levels greater
than those shown in
Table 1
. If operating levels are higher than
specified, readjust the float in order to attain the recommended
operating level.
• Closely monitor the water level in the cold water basin and adjust
the level if necessary during the first 24 hours of operation.
• Operating at the recommended water level will ensure that the unit
basin contains sufficient water volume to prevent air entrainment in
the circulating pump during system start-up and provides sufficient
excess basin capacity to accept the total system pulldown volume.
Figure 10. Water Make-Up Valve Assembly
Float Valve
Float Arm Assembly
Wing
Nuts
All Threaded Rod
Float Ball