Carrier 58SP0B Installation, Start-Up, Operating And Service And Maintenance Instructions page 42

58SP0B/58SP1B: Installation, Start–Up, Operating and Service and Maintenance Instructions
Method 2: The active continuous fan speed (CFn, CF2 or CF3) can be
selected via the service tech app.
5. Heat pump
See Fig. 24 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 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
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 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 fan airflow.
Wiring Diagram
Refer to Fig. 47 for wiring diagram.
Troubleshooting
Refer to the service label (see Fig.
Fig. 52) 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.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
46). The Troubleshooting Guide (see
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