ECH EVAPORATIVE CONDENSERS
OPERATION
140.910-IOM (DEC 13)
Page 9
•
Set the makeup valve float so the water shuts off at the
overflow level.
•
Start the spray pump and check for the proper rotation
indicated by the arrow on the pump cover. On installations
where the unit pump was not furnished by Johnson
Controls, a globe valve should be installed in the pump
discharge line and the pump flow rate adjusted to the
correct water flow and pressure (2 psig at spray header
connection).
CAUTION
Pressure greater than 10.0 psig may cause damage to the
distribution system.
•
Inspect the spray nozzles and heat transfer section.
•
Open the supply valve slowly until the design flow is
reached, based on the pressure in the distribution system.
Refer to the Water Distribution System section under
MAINTENANCE for more details (see Table of Contents).
•
Open the valve in the unit bleed line and adjust the bleed
by closing or opening the valve.
•
Once the unit is operating, check the current and voltage
of all three phases (legs) of the fan motor with a heat load
on the unit under warm ambient conditions. The current
must not exceed the nameplate ratings.
•
Check the operation of the optional vibration cutout
switch.
After 24 hours of operation under thermal load, perform the
following services:
•
Check the unit for any unusual noise or vibrations.
•
Check the operating water level in the cold water basin.
Adjust the balancing valves if necessary.
•
Adjust makeup valve if necessary.
•
Check the belt tension and readjust if necessary.
•
Inspect the spray nozzles and heat transfer section.
ExTENDED SHUTDOWN
WARNING
Do not perform any service on or near the fans, motors,
drives, or inside the unit without first ensuring that the fans
and the pumps are disconnected and locked out.
Perform the following services whenever the unit is shutdown
in excess of 3 days:
•
If the unit is mounted on vibration isolators or isolation
rails, refer to the manufacturer’s guidelines before loading/
unloading weight from the unit.
•
Drain the cold water basin and all the piping (excluding the
coils) that will be exposed to freezing temperatures. Heat
trace and insulate all exposed piping.
•
Clean all debris, such as leaves and dirt, from the interior
and exterior of the unit.
•
Clean and flush the water distribution system and cold
water basin with the basin strainer in place.
•
Leave the cold water basin drain open so rain and melting
snow will drain from the unit.
•
Clean the basin strainer and re-install.
•
Cover the fan discharge opening to keep out dirt and debris.
•
Lubricate the fan shaft bearings, motor base, and motor
base adjusting screw.
•
Close the shutoff valve in the makeup water line (supplied
by others), and drain all exposed makeup water piping.
Heat trace and insulate all exposed piping.
•
Inspect the protective finish on the unit. Clean and refinish
as required. Refer to the Corrosion Protection section for
more details (see Table of Contents).
•
Secure the fan motor starting device in the “OFF” position to
ensure personal safety in case of future inspection or service.
COLD WEATHER OPERATION
Frick condensers can be operated at subfreezing ambient tem-
peratures provided proper operating methods are established
and diligently followed.
Inspection and Maintenance
•
Carry out the frequent visual inspections and routine
maintenance services during operation in subfreezing
weather.
•
Ensure all controls for capacity and freeze protection are
set properly and functioning normally.
•
Prevent excessively high water levels and possible overflow
of the cold water basin due to overpumping, clogged
strainers, or makeup valve malfunction.
•
Resolve any icing condition that may severely develop
to damage the unit or the supports or impair the system
performance.
Fan Section Icing Protection
There are three basic operational methods which can be used to
provide the system’s required cooling: Temperature Setting, Fan
Control, and Dry Operation. The method of controls employed on
a given application depends upon the climatic extremes which
are expected, the variations in heat load that will be encountered,
and the compatibility of the control system with other portions
of the installation. Effective icing control in subfreezing ambient
conditions will require a combination of these three methods.
Temperature Setting
Low leaving fluid temperature promotes ice formation. During
operation in subfreezing ambient temperatures, maintain the
leaving fluid temperature as high as possible. Ensure the unit
operates with the maximum possible heat load. The recom-
mended minimum fluid temperature is 45°F.
Fan Control
Reduce the unit capacity by cycling fans thus modulating the
airflow through the unit. Rapid on-off cycles can cause the fan
motor to overheat. Set the controls to allow a maximum of 6
on-off cycles per hour. Periodically, cycle the fans off to prevent
ice formation and/or to melt ice that accumulates on the intake
louvers or combined inlet shields and face of the fill.
Fan Cycling
: Operate each unit with the highest thermal load
it can handle, rather than evenly dividing the total heat load
