40
High--cooling airflow is based on the A/C selection shown
in Fig. 39.
NOTE
: When transitioning from low--cooling to high--cooling the
outdoor unit compressor will shut down for 1 minute while the
furnace blower motor BLWM transitions to run at high--cooling
airflow.
The electronic air cleaner terminal EAC--1 is energized
with 115 vac whenever the blower motor BLWM is
operating.
When the thermostat is satisfied, the R to G--and--Y circuit
are opened. The outdoor unit stops, and the furnace blower
BLWM and electronic air cleaner terminal EAC--1 will
remain energized for an additional 90 seconds. Jumper Y1
to DHUM to reduce the cooling off--delay to 5 seconds.
(See Fig. 33.)
3.
Two--Stage Thermostat and Two--Speed Cooling
(See Fig. 49 for thermostat connections)
NOTE
: The air conditioning relay disable jumper ACRDJ must
be disconnected to allow thermostat control of the outdoor unit
staging. (See Fig. 33.)
The thermostat closes the R to G and--Y1 circuits for low
cooling or closes the R to G and--Y1--and--Y2 circuits for
high--cooling. The R to Y1 circuit starts the outdoor unit
on low--cooling speed, and the R to G--and--Y1 circuit
starts the furnace blower motor BLWM on low--cooling
airflow which is the true on--board CF selection as shown
in Fig. 41. The R to Y1--and--Y2 circuits start the outdoor
unit on high--cooling speed, and the R to G--and--Y/Y2
circuits start the furnace blower motor BLWM at
high--cooling airflow. High--cooling airflow is based on the
A/C selection shown in Fig. 39.
The electronic air cleaner terminal EAC--1 is energized
with 115 vac whenever the blower motor BLWM is
operating.
When the thermostat is satisfied, the R to G--and--Y1 or R
to G--and--Y1--and--Y2 circuits are opened. The outdoor
unit stops, and the furnace blower BLWM and electronic
air cleaner terminal EAC--1 will remain energized for an
additional 90 seconds. Jumper Y1 to DHUM to reduce the
cooling off--delay to 5 seconds. (See Fig. 33.)
Thermidistat Mode
See Fig. 43--46 for Thermidistat connections.
The dehumidification output, DHUM on the Thermidistat should
be connected to the furnace control thermostat terminal DHUM.
When there is a dehumidify demand, the DHUM input is activated,
which means 24 vac signal is removed from the DHUM input
terminal. In other words, the DHUM input logic is reversed. The
DHUM input is turned ON when no dehumidify demand exists.
Once 24 vac is detected by the furnace control on the DHUM
input, the furnace control operates in Thermidistat mode. If the
DHUM input is low for more than 48 hours, the furnace control
reverts back to non--Thermidistat mode.
The cooling operation described in item 3. above applies to
operation with a Thermidistat. The exceptions are listed below:
1.
Low cooling
--When the R to G--and--Y1 circuit is closed
and there is a demand for dehumidification, the furnace
blower motor BLWM will drop the blower airflow to 86%
of low--cooling airflow which is the true on--board CF se-
lection as shown in Fig. 39.
2.
High coolin
g--When the R to G--and Y/Y2 circuit is closed
and there is a demand for dehumidification, the furnace
blower motor BLWM will drop the blower airflow to 86%
of high--cooling airflow. 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.
Super--Dehumidify Mode
Super--Dehumidify mode can only be entered if the furnace control
is in Thermidistat mode and there is a demand for
dehumidification. The cooling operation described in item 3.
above also applies to operation with a Thermidistat. The exceptions
are listed below:
1.
Low cooling
--When the R to Y1 circuit is closed, R to G
circuit is open, and there is a demand for dehumidification,
the furnace blower motor BLWM will drop the blower air-
flow to 65% of low--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. Low--cool-
ing airflow is the true on--board CF selection as
shown in Fig. 39.
2.
High cooling
--When the R to Y/Y2 circuit is closed, R to G
circuit is open, and there is a demand for dehumidification,
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 air-
flow 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.
355B
A
V
