11
operation
Fan Cycling Limits:
Considering the normal fan and motor sizes utilized on NC towers,
anticipate that approximately 4 to 5 starts per hour are allowable.
If your tower is equipped with a two-speed motor, greater opportunity
for temperature control is afforded you. 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.
Do not start the motor more than four to five times per hour (each
low speed start and each high speed start count as one start).
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
Marley Technical Report H-001
,
“Cooling Tower Energy and its
Management”
available from your Marley sales representative or you
can download a copy from Marley’s website at spxcooling.com.
Freezing Weather Operation
During operation in subfreezing 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
Marley Technical Report
H-003
,
“Operating Cooling Towers in Freezing Weather,”
augmented by
the following guidelines. Available for download at spxcooling.com.
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.
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:
Note
Note
Note
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