Bryant 702B - Manual (Page 25)

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CONTROLS
SEQUENCE OF OPERATION
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
(evaporator) fan time delay relay (TDR). 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 set of normally open contacts of TDR
close and complete the circuit through IFM. The IFM starts
instantly.
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) deenergizing the compressor contactor
and opening the contacts supplying power to compressor/OFM.
After a 60-second delay, the IFM shuts off. If the thermostat fan
selector switch is in the “ON” position, the IFM will run
continuously.
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 TDR. 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 and the
TDR. After a 60-second delay, the IFM shuts off. If the
thermostat fan selector switch is in the “ON” position, the IFM will
run continuously.
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.
ICM FIOP Models Only — 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.