5
high--cooling airflow. High--cooling airflow is based on
the A/C selection shown in Table 1.
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. SUPER--DEHUMIDIFY MODE
Super--Dehumidify mode can only be entered if the furnace control
is in the dehumidify mode and there is a demand for
dehumidification. The cooling operation described in item 3.
above also applies to operation with a dehumidify enabled
thermostat. 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% 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
selection as shown in Table 1.
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% 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 Table 1.
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.
6. 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 Table 1. Factory default is shown in Table 1.
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 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 (60 seconds in
low--heat, and 35 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 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 switch to 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.
a. Continuous Blower Speed Selection from Thermostat
To select different continuous--blower airflows from the room
thermostat, momentarily turn off the FAN switch or push--button
on the room thermostat for 1--3 seconds after the blower motor
BLWM is operating. The furnace control CPU will shift the
continuous--blower airflow from the factory setting to the next
highest CF selection airflow as shown in Table 1. Momentarily
turning off the FAN switch again at the thermostat will shift the
continuous--blower airflow up one more increment. If you repeat
this
procedure
enough
you
will
eventually
shift
the
continuous--blower airflow to the lowest CF selection as shown in
Table 1. The selection can be changed as many times as desired
and is stored in the memory to be automatically used following a
power interruption.
7. HEAT PUMP DEFROST
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 midrange 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 Appendix A)
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 IDM
ON at medium 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 midrange airflow for 15 seconds, then
OFF.
d. After shutting the blower motor OFF the furnace control
CPU shuts the inducer motor IDM.
NOTE
:
The EAC terminals are energized when the blower
is operating.
After the component test is completed, 1 or more status codes (11,
25, 41, or 42) will flash. See Service Label on blower access panel
or Service/Status Code Instructions for explanation of status codes.
NOTE
:
To repeat component test, turn setup switch
SW1--6 to OFF and then back ON.