24
FORM CIM 0203
HEAT PUMP HEATING SEQUENCE OF
OPERATION
1. Before starting the unit, make sure electrical
power has been turned on for a minimum of
24 hours. This assures that any liquid refriger-
ant is “driven” out of the crankcase.
2. For water-cooled units, make sure condenser
water is available. Open all stop valves. Verify
that cooling tower is functioning, if this is the
source of condensing water supply. Start cir-
culating the water to the water condenser.
3. The following sequence is based on the unit
being controlled by a room thermostat. If an-
other control type is being utilized, reference
the instructions for that device may be re-
quired.
a. Lower thermostat setpoint to the lowest
level.
b. Set System switch to “OFF” position.
c. Set Fan switch to “AUTO” position.
d. Moving the Fan switch to the “ON” posi-
tion should cause the evaporator blower mo-
tor to run. Moving the Fan switch back to
“AUTO” should stop the blower.
e. Move the System switch to the “HEAT” po-
sition. Slowly raise the thermostat setting
to call for heating. The evaporator blower
should start (assumes Fan switch set to
“AUTO”) and the System No. 1 compres-
sor will start.
f. On those units with multiple compressors,
if the thermostat setpoint continues to be
raised, the second compressor should then
start.
g. Set room thermostat at desired space tem-
perature. Set the Fan switch to “AUTO” or
“ON”. The unit will cycle as required to
maintain conditions.
Summary of Contents for 4CA1901
Page 2: ...2 FORM CIM 0203 ...
