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20
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 15 psig and 50 psig for proper
operation. BAC recommends a pressure regulator valve (provided by others) for
pressures over 50 psig.
• 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
as stated in
Table 1
on
page 9
.
• With the design thermal load and the average water pressure (15 to 50 psig) 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 pull-down volume.
Optional Electric Water Level Control Package
As an option, an electric water level control package is available in lieu of the mechanical
make-up assembly. The package consists of a probe-type liquid level control assembly
and a slow-closing solenoid valve. Stainless steel electrodes, factory-set at predetermined
lengths, extend from an electrode holder into the cold water basin. For more information,
refer to the
Electric Water Level Control Operation & Maintenance Manual
available at
www.BaltimoreAircoil.com.
• Clean the stainless steel electrodes periodically to prevent accumulations of scale,
corrosion, sludge, or biological growth, which could interfere with the electrical circuit.
• The water level is maintained at the recommended operating level regardless of the
system thermal load. Therefore, it is not recommended that the operating level be
adjusted.
• During the start-up of units equipped with the electric water level control package,
bypass the control unit in order to fill the unit to the overflow connection.
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.
