23
FORM CIM 0203
SEQUENCE OF OPERATION
COOLING 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. Raise thermostat setpoint to highest level.
b. Set System switch to “OFF” position.
c. Set Fan switch to the “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 “COOL” po-
sition. Slowly lower the thermostat setting
to call for cooling. The evaporator blower
should start (assuming the Fan switch is set
to “AUTO”) and the System No. 1 compres-
sor should start.
f. On those units with multiple compressors,
if the thermostat setpoint continues to be
lowered, the second compressor should then
start.
g. Set room thermostat at desired space tem-
perature and the Fan switch to “AUTO” or
“ON”. The unit will cycle as required to
maintain conditions.
4. Chill water sequence is the same as above, ex-
cept compressor activation is replaced by the
chill water valve function.
5. Heat pump cooling sequence is the same as
above, except the reversing valve will also be
activated when the compressor cycle is started.
HEATING SEQUENCE OF OPERATION
(OTHER THAN HEAT PUMP)
1. 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 (assuming the Fan switch is set
to “AUTO”) and the electric heating ele-
ment will be activated.
f. On those units with a second stage of elec-
tric heat, if the thermostat setpoint contin-
ues to be raised, the second stage of electric
heat should then be activated.
NOTE: Units with more than one stage of
electric heat require a two stage heat ther-
mostat.
g. Set room thermostat at desired space tem-
perature and set the Fan switch to “AUTO”
or “ON”. The unit will cycle as required to
maintain conditions.
Содержание 4CA1901
Страница 2: ...2 FORM CIM 0203 ...
