22
CONTROLS
Operating sequence
Cooling — When the system thermostat calls for cooling, 24 V is
supplied to the “Y” and “G” terminals of the thermostat. This
completes the circuit to the contactor coil (C) and indoor fan
board. The normally open contacts of C close and complete the
circuit to compressor motor (COMP) and to outdoor (condenser)
fan motor (OFM). Both motors start instantly. The IFM starts
according to the selection pin set--up on the Easy Select Board.
On the loss of the thermostat call for cooling, 24 V is removed
from both the “Y” and “G” terminals (provided the fan switch is in
the “AUTO” position) de--energizing the compressor contactor and
opening the contacts supplying power to compressor/OFM. After a
preselected delay, the I FM shuts of f. If the thermostat fan selector
switch is in the “ON” position, the IFM will run continuously at
speed selected on Easy Select Board
Heating — If accessory electric heaters are installed, on a call for
heat, circuit R--W is made through the thermostat contacts. Circuit
R--G is made which energizes the IFM. If the heaters are staged,
then the thermostat closes a second set of contacts (W2) when
second stage is required. When thermostat is satisfied, contacts
open, deenergizing the heater relay. After a preselected delay , the
IFM shuts of f. If the thermostat fan selector switch is in the “ON”
position, the IFM will run continuously at speed selected on Easy
Select Board.
NOTE: On units with a Time Guard
®
II device: Once the
compressor has started and then stopped, it cannot be restarted
again until 5 minutes have elapsed.
The indoor blower operation with a call for fan operation (G) in
cooling mode will perform by the on/off delay profile selected at
start up on the Easy Select Board.
50XP
