Specifications are subject to change without notice.
41
441 01 4200 01
ing on selection at blower--OFF delay switches). The
furnace control CPU is factory--set for a 120--second
blower--OFF delay.
2.
Cooling mode
The thermostat “calls for cooling”.
a.
Single--Speed Cooling
--
See Fig. 25 for thermostat connections
The thermostat closes the R--to--G--and--Y circuits. The
R--to-- Y circuit starts the outdoor unit, and the R--to--
G--and--Y/Y2 circuits start the furnace blower motor
BLWM on cooling airflow. Cooling airflow is based
on the A/C selection shown in Fig. 40. The electronic
air cleaner terminal EAC--1 is energized with 115 vac
when the blower motor BLWM is operating.
When the thermostat is satisfied, the R--to--G--and--Y
circuits are opened. The outdoor unit will stop, and the
furnace blower motor BLWM will continue operating
at cooling airflow for an additional 90 seconds.
Jumper Y/Y2 to DHUM to reduce the cooling off--de-
lay to 5 seconds. (See Fig. 23)
b.
Two--Stage Thermostat and Two--Speed Cooling
See Fig. 26 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. 23)
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 at low--cooling airflow which is the
true on--board CF (continuous fan) selection as shown in Fig. 40.
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 (air conditioning)
selection shown in Fig. 40.
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. 23)
3.
Thermidistat Mode
See Fig. 25--27 for thermostat connections.
The dehumidification output, DHUM on the Thermidistat
should be connected to the furnace control thermostat ter-
minal 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 2. above also ap-
plies to operation with a Thermidistat. The exceptions are
listed below:
a.
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 percent of cooling airflow which is the
true on--board CF (continuous fan) selection as shown
in Fig. 40.
b.
High cooling
--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 percent of cooling airflow. Cooling air-
flow is based on the A/C (air conditioning) selection
shown in Fig. 40.
c.
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.
4.
Super--Dehumidify Mode
Super--Dehumidify mode can only be entered if the fur-
nace control is in the Thermidistat mode and there is a de-
mand for dehumidification. The cooling operation de-
scribed in item 3. above also applies to operation with a
Thermidistat. The exceptions are listed below:
a. 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
airflow to 65 percent 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--cooling airflow is
the true on--board CF (continuous fan) selection as
shown in Fig. 40.
b. 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
airflow to 65 percent 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 (air conditioning) selection shown in
Fig. 40.
c. 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.
5.
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 (continuous fan) selection shown in Fig.
40. Factory default is shown in Fig. 40. 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, heating 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 (25 seconds in
heat), allowing the furnace heat exchangers to heat up
more quickly, then restarts at the end of the blower--ON
delay period at heating airflow.
The
blower
motor
BLWM
will
revert
to
continuous--blower airflow after the heating cycle blower
off--delay is completed.
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 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
