78 440 01 4801 00
Specifications subject to change without notice.
matically changes the timing sequence to avoid long blower
off times during demand defrost cycles. Whenever W/W1 is
energized along with Y1 or Y/Y2, the furnace control CPU
will transition to or bring on the blower motor BLWM at
cooling airflow or low-- heat airflow whichever is lowest.
The blower motor BLWM will remain on until the main
burners ignite then shut OFF and remain OFF for 25 sec-
onds before coming back on at heating airflow. When the
W/W1 input signal disappears, the furnace control begins a
normal inducer post--purge period while changing the blow-
er airflow. If Y/Y2 input is still energized the furnace con-
trol CPU will transition the blower motor BLWM airflow to
cooling airflow. If Y/Y2 input signal disappears and the Y1
input is still energized the furnace control CPU will transi-
tion the blower motor BLWM to low--cooling airflow. If
both the Y1 and Y/Y2 signals disappear at the same time,
the blower motor BLWM will remain on at low--heat air-
flow for the selected blower-- OFF delay period. At the end
of the blower-- OFF delay, the blower motor BLWM will
shut OFF unless G is still energized, in which case the blow-
er motor BLWM will operate at continuous blower airflow.
344602--- 2 REV C
A190261
Fig. 75 -- Wiring Diagram
To Next Page
Loading...
