Dry Operation - SPX Marley LW032 B Series User Manual

Note
Note
operation
fluid flow rate will cause the cold process fluid temperature to decrease
slightly. However, at a given heat load (see formula above), process fluid
flow reductions also cause an increase in the incoming hot process fluid
temperature and thermal range.
4. Air flow rate: Reducing air flow through the fluid cooler causes the cold
process fluid temperature to rise. This is the recommended method by
which to control leaving process fluid temperature.
For greater insight on process fluid temperature control, please read Mar-
ley Technical Report H-001 "Cooling Tower Energy Management",
available at spxcooling.com.
Pump cycling limits: Cycling the recirculating water pump(s) to control pro-
cess fluid temperature is not typically recommended. If the recirculating
water pumps(s) are cycled as part of normal system operation, care must
be exercised — frequent wet/dry cycles may lead to premature scaling of
the coil surface. Motor cycling limits apply.
Dampers: If equipped, the positive closure damper system is designed to help
prevent heat loss from the coil due to air movement caused by convec-
tion or wind conditions when both the fans and pump are off. Dampers
are installed above the discharge of the fans and are opened/closed via
a switch on the control panel door.
Operation of the fans and pump is only enabled when the dampers
are opened.

Dry Operation

Also refer to the Freezing Weather Operation and Protection Against
Coil Freezing sections.
LW fluid cooler models may be operated dry without recirculating water during
colder weather as heat load and ambient conditions permit.
If dry operation is intended and the recirculating water is at risk of freezing,
the recirculating pump should be turned off, and the water in the collection
basin, pump and make-up supply piping should be drained.
Care must be exercised when cycling the recirculating water pump(s)— frequent
wet/dry cycles may lead to premature scaling of the heat transfer surface.
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