F80CTL & G80CTL: Installation, Start–Up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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motor BLWM will operate at continuous blower airflow.
Continuous blower airflow selection is initially based on the CF
(continuous fan) selection, see Fig. 14. (The factory default is
shown in Fig. 14. Terminal EAC-1 is energized as long as the
blower motor BLWM is energized.
During a call for heat, the furnace control CPU will transition the
blower motor BLWM to continuous blower airflow, low-heat
airflow, or the mid-range airflow, whichever is lowest. The blower
motor BLWM will remain ON until the main burners ignite then
shut OFF and remain OFF for the blower-ON delay (45 seconds in
low-heat, and 25 seconds in high-heat), allowing the furnace heat
exchangers to heat up more quickly, then restarts at the end of the
blower-ON delay period at low-heat or high-heat airflow,
respectively.
The blower motor BLWM will revert to continuous-blower airflow
after the heating cycle is completed. In high-heat, the furnace
control CPU will drop the blower motor BLWM to low-heat airflow
during the selected blower-OFF delay period before transitioning to
continuous-blower airflow.
When the thermostat “calls for low-cooling”, the blower motor
BLWM will switch to operate at low-cooling airflow. When the
thermostat is satisfied, the blower motor BLWM will operate an
additional 90 seconds at low-cooling airflow before transitioning
back to continuous-blower airflow.
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.
NOTE: If the blower-off delay is set to the maximum, the adjustable
continuous-fan feature is locked (i.e., fan speed cannot be changed from
its current setting).
7. Heat pump
See Fig. 30 - Fig. 31 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, low-heat airflow, or
the mid-range 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/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 low-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.
8. Component test
The furnace features a component test system to help diagnose a
system problem in the case of a component failure. To initiate the
component test procedure, ensure that there are no thermostat
inputs to the control and all time delays have expired. Turn on setup
switch SW1-6, see Fig. 32.
NOTE: The component test feature will not operate if the control is
receiving any thermostat signals or until all time delays have expired.
The component test sequence is as follows:
a. The furnace control CPU turns the inducer motor ON at
high-heat speed and keeps it ON through step c.
b. After waiting 10 seconds the furnace control CPU turns the hot
surface igniter ON for 15 seconds, then OFF.
c. The furnace control CPU then turns the blower motor BLWM on
at mid-range airflow for 15 seconds, then OFF.
d. After shutting the blower motor OFF the furnace control CPU
switches the inducer to low-heat speed for 10 seconds, then OFF.
NOTE: The EAC terminals are energized when the blower is operating.
After the component test is completed, 1 or more status codes (heartbeat,
2+5) will show. See component test section or Service Label (Fig. 49)
for explanation of status codes.
NOTE: To repeat component test, turn setup switch SW1-6 to OFF and
then back ON.
Wiring Diagram
Refer to Fig. 53 for wiring diagram.
Troubleshooting
Refer to the service label (see Fig. 49) for some troubleshooting
information. Also, the Troubleshooting Guide (see Fig. 54) can be a
useful tool in isolating furnace operation problems. Beginning with the
word “Start,” answer each question and follow the appropriate arrow to
the next item. The Guide will help to identify the problem or failed
component. After replacing any component, verify correct operation
sequence.
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