Tempstar (F/G)9MAC0601714A Service And Technical Support Manual page 31

SERVICE AND TECHNICAL SUPPORT MANUAL
When the thermostat "calls for high-cooling", the blower motor
BLWM will operate at high cooling airflow. When the thermostat
is satisfied, the blower motor BLWM will operate an additional
90 seconds at high-cooling airflow before transitioning back to
continuous-blower airflow.
When the R to G circuit is opened, the blower motor BLWM will
continue operating for an additional 5 seconds, if no other
function requires blower motor BLWM operation.
Heat Pump
See Thermostat Instructions for thermostat connections. When
installed with a heat pump, the furnace control automatically
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,
minimum-heat airflow, or the mid-range airflow, whichever is
lowest. The blower motor BLWM will remain on until the main
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burners ignite then shut OFF and remain OFF for 25 seconds
before coming back on at modulating heat airflow. When the
W/W1 input signal disappears, the furnace control begins a
normal inducer post-purge period while changing the blower
airflow. If Y/Y2 input is still energized the furnace control 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 transition 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 minimum-heat airflow 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 blower motor BLWM will operate
at continuous blower airflow.
Component Self Test
Refer to page 16 for instructions.
Specifications subject to change without notice.
Gas Furnace: (F/G)9MAC
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