Cold Weather Operation; Unit Layout; Freeze Protection Of Recirculating Water - EVAPCO ESW Series Operation And Maintenance Instruction

Cold Weather Operation

EVAPCO counterflow evaporative cooling equipment is well suited to operate in cold weather conditions. The counterflow design
encases the heat transfer media (fill and/or coils) completely, and protects it from the outside elements such as wind which can cause
freezing in the unit.
When the evaporative cooling unit is going to be used during cold weather conditions, several items need to be considered including unit
layout, recirculating water, unit recirculating piping, unit heat transfer coils, unit accessories and capacity control of the units.

Unit Layout

Adequate unobstructed air flow must be provided for both the intake and discharge from the unit. It is imperative that the equipment
minimize the risk of recirculation. Recirculation can result in condensation freezing the inlet louvers, fans and fan screens. The buildup of
ice on these areas can adversely affect air flow and in more severe cases, lead to failure of these components. Prevailing winds can create
icing conditions on the inlet louvers and fan screens adversely affecting airflow to the unit.
For additional information on unit layout, please refer to EVAPCO's Equipment Layout Manual.

Freeze Protection of Recirculating Water

The simplest and most effective way of keeping the recirculated water from freezing is to use a remote sump. With a remote sump, the
recirculating water pump is mounted remotely at the sump and whenever the pump is shut off, all recirculating water drains back to the
sump. Recommendations for sizing the remote sump tank and recirculating water pumps for coil products are presented for Evaporative
Condensers and Closed Circuit Coolers in their respective catalog bulletin. The pressure drop through the water distribution system
measured at the water inlet is as follows in Table 5.
If a remote sump cannot be used, basin heaters are available to keep the recirculating water from freezing when the pump is turned off.
Electric heaters, hot water coils, steam coils or steam injectors may be used to heat the basin water when the unit is shut down. However,
the basin heater will not prevent the external water lines, pump or pump piping from freezing. The make-up water supply, overflow and
drain lines, as well as the pump and pump piping up to the overflow level must be heat traced and insulated to protect them from
damage. Any other connections or accessories at or below the water level, such as electronic water level controllers, must also be heat
traced and insulated.
A condenser or cooler cannot be operated dry (fans on, pump off) unless the water is completely drained from the pan. The pan heaters
are sized to prevent pan water from freezing only when the unit is completely shut down.
NOTE: Using basin heaters will not prevent the fluid in the coils, nor the residual water in the pump or pump piping from freezing.
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