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935SB: Installation, Start-up, Operating and Service Maintenance Instructions
BLWM at HEAT speed during the selected blower-OFF delay
period before reverting to continuous-blower speed. When the
thermostat "calls for low-cooling", the blower motor BLWM will
switch to operate at low-cool speed. When the thermostat is
satisfied, the blower motor BLWM will operate at low-cooling
speed for the cooling off delay setting time before reverting back to
continuous-blower speed.
When the thermostat "calls for high-cooling", the blower motor
BLWM will operate at COOL speed. When the thermostat is
satisfied, the blower motor BLWM will operate at high-cooling
speed for the cooling off delay setting time before reverting back to
continuous-blower speed. When the R-to-G circuit is opened, the
blower motor BLWM will continue operating for an additional 5
sec, if no other function requires blower motor BLWM operation.
4. Heat pump
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 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 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 seconds before
coming back on at heating airflow. When the W 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 heat airflow for the selected
blower-OFF delay period. If the R-to-W-and-Y1 signals disappear,
leaving the G signal, the furnace control CPU will transition the
blower motor BLWM to CONTINUOUS FAN speed after the
selected heating blower-OFF delay period.
Wiring Diagrams
Refer to
Fig. 62
for wiring diagram.
Troubleshooting
Refer to the service label. (see
and the Troubleshooting Guide (see
isolating furnace operation problems. The Guide will help to identify the
problem or failed component. After replacing any component, verify
correct operation sequence.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
Fig.
61), wiring diagram (see
Fig.
70) can be a useful tool in
Fig.
62),
62
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