Gray Water And Reclaimed Water; Air Contamination; Cold Weather Operation; Unit Layout - EVAPCO ATC-E Operation And Maintenance Instruction Manual

Operation and Maintenance Instructions

Gray Water and Reclaimed Water

The use of water reclaimed from another process as a source of makeup water for evaporative cooling equipment can be
considered as long as the resultant recirculating water chemistry conforms to the parameters noted in Table 4 . It should be
noted that using water reclaimed from other processes may increase the potential of corrosion, microbiological fouling, or scale
formation . Gray water or reclaimed water should be avoided unless all of the associated risks are understood and documented as
part of the site specific treatment plan .

Air Contamination

Evaporative cooling equipment draws in air as part of normal operation and can scrub particulates out of the air . Do not locate
the unit next to smokestacks, discharge ducts, vents, flue gas exhausts, etc . because the unit will draw in these fumes which may
lead to accelerated corrosion or deposition potential within the unit . Additionally, it is important to locate the unit away from the
building's fresh air intakes to prevent any drift, biological activity, or other unit discharge from entering the building's air system .

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- Bulletin 311 .

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 on page 21 .
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 or steam coils 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 .
Note: Using basin heaters will not prevent the fluid in the coils, nor the residual water in the pump or pump piping from
freezing .
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 .
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