39
2.
High cooling
--When the R to Y/Y2 cicuit is closed, R to
G circuit is open, and there is a demand for
dehumidifiation, the furnace blower motor BLWM will
drop the blower to 65% of high--cooling airflow for a
maximum of 10 minutes each cooling cycle or until the R
to G circuit closes or the demand for dehumidification is
satisfied. High--cooling airflow is based on the A/C
selection shown in Fig. 39.
3.
Cooling off--delay
--When the “call for cooling” is
satisfied and there is a demand for dehumidification, the
cooling blower--off delay is decreased from 90 seconds to
5 seconds.
CONTINUOUS BLOWER MODE
When the R to G circuit is closed by the thermostat, the blower
motor BLWM will operate at continuous--blower airflow.
Continuous blower airflow selection is initially based on the CF
selection shown in Fig. 39. Factory default is shown in Fig. 39.
Terminal EAC--1 is energized as long as the blower motor
BLWM is energized.
During a call for heat, the blower BLWM will transition the
blower motor BLWM to continuous blower airflow, low--heat
airflow, or the midrange 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 (30 seconds
in low--heat and 35 seconds in high--heat) allowing the furnace
heat exchangers to heat 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 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.
58U
VB
