SPX Cooling Technologies Marley MH 05-116E - Manual (Page 17)

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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 fluid cooler 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 fluid cooler fill. Certain guidelines should be
followed:
1. Do not allow the fluid cooler's leaving process fluid temperature to
drop below 45°F. If such low temperature operation is necessary or
beneficial to your process, establish the minimum allowable level 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 louvers, you must
increase the allowable cold water temperature.
If the minimum allowable cold process fluid temperature is estab-
lished at or near minimum heat load, it should be safe for all operat-
ing conditions.
Having established the minimum allowable cold water temperature,
maintaining that temperature can be accomplished by fan manipulation,
as outlined in
Item 4 under Fluid Cooler Operation.
2. As cold air enters the louvers, it causes the water flowing over the fill
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.
Therefore, if excessive ice forms on the louvers, stop the fan for a few
minutes. With the fan off, the water flow will increase in the vicinity of
the louvers and reduce the ice buildup.
3. Under extended extreme cold conditions, it may be necessary to op-
erate the fan in reverse. This forces warm air out through the louvers,
melting any accumulated ice—adequate heat load must be available.
➠
Operation
Note
Caution