Seasonal Shut-Down Checklist; Basic Closed Circuit Cooler/Condenser Sequence Of Operation - EVAPCO ATC-E Operation And Maintenance Instruction

Operation and Maintenance Instructions

Seasonal Shut-Down Checklist

When the system is to be shut down for an extended period of time, the following services should be performed.
1. The evaporative cooling unit cold water basin should be drained
2. The cold water basin should be flushed and cleaned with the suction strainer screens in place.
3. The suction strainer screens should be cleaned and re-installed.
4. The cold water basin drain should be left open.
5. The fan shaft bearings and motor base adjusting screws should be lubricated. This should also be performed if the unit is
going to sit idle prior to initial start-up.
6. The make-up water supply, overflow and drain lines, as well as the recirculating pump and pump piping up to the overflow
level must be heat traced and insulated to account for any residual water.
7. The finish of the unit should be inspected. Clean and refinish as required.
8. The fan, motor and pump bearings need to be turned at least once a month by hand. This can be accomplished by
making sure the unitʼs disconnect is tagged and locked out, and grasping the fan assembly, rotating it several turns.
9. Closed Circuit Coolers only - If the recommended minimum fluid flows thru the heat transfer coil cannot be maintained,
and an anti-freeze solution is not in the coil, the coil must be drained immediately whenever the system pumps are shut
down or flow stops during freezing conditions. This is accomplished by having automatic drain valves and air vents in the
piping to and from the cooler. Care must be taken to ensure that the piping is adequately insulated and sized to allow the
water to flow quickly from the coil. This method of protection should be used only in emergency situations and is neither a
practical nor recommended method of freeze protection. Coils should not be drained for an extended period of time, as
internal corrosion may occur. See Cold Weather Operation section of this document for more details.
See fan and pump manufacturer maintenance and long term storage instructions for more detailed instructions.

Basic Closed Circuit Cooler/Condenser Sequence of Operation

Note: The EVAPCO WDW sequence of operation is unique and is explained in detail in the Sage Panel Control Manual,
EVAPCO Bulletin 117.
Note: The eco-ATW/eco-ATWE sequence of operation is unique and is explained in detail in the Sage
Control Manual.
System Off / No Load
The system pumps and fans are off. If the basin is full of water a minimum basin water temperature of 40ºF must be maintained to
prevent freezing. This can be accomplished with the use of optional basin heaters. See the "Cold Weather Operation" section of
this bulletin for more details on cold weather operation and maintenance.
System/Condensing Temperature Rises
The recirculation pump turns on. The unit will provide approximately 10% cooling capacity with only the pump running. If the unit
has positive closure dampers they should be fully opened before the pumps turn on.
If the system temperature continues to rise, the unit fan is cycled on. For a variable speed controller, the fans are turned on to
minimum speed. See the "Fan System – Capacity Control" section of this bulletin for more details on fan speed control options. If
the system temperature continues to rise, then the fan speed is increased as required, up to full speed.
Note: During sub-freezing weather the minimum recommended speed for variable speed controllers is 50%. ALL FANS IN
OPERATING CELLS OF MULTIPLE CELL UNITS MUST BE CONTROLLED TOGETHER TO PREVENT ICING ON THE FANS.
System Temperature Stabilizes
Control the leaving fluid temperature (closed circuit coolers) or condensing temperature (evaporative condensers) by modulating
the fan speeds with variable speed drives or by cycling fans on and off with single or two-speed drives.
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2 , Sage 3 Panel