59TP6C: Installation, Start-up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
73
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,
dehumidification capability is activated. If the DHUM input is
removed for more than 48 hours, the furnace control reverts back to
non-dehumidification mode.
The cooling operation described in item 3 above also applies to
operation with a dehumidification thermostat. 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 low cooling airflow
demand is reduced by 10 percent.
b. High cooling-When the R-to-G-and Y/Y2 circuit is closed and
there is a demand for dehumidification, high cooling airflow
demand is reduced by 10 percent.
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.
5. Continuous Fan Mode
When the R-to-G circuit is closed by the thermostat, the blower
motor BLWM will operate at fan airflow. Continuous fan airflow
selection is initially based on the CF (continuous fan) selection
shown in Fig. 59. Factory default is shown in Table 20. 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 fan 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 the
blower-ON delay (45 seconds in low-heat, and 25 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 fan 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 fan airflow.
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 low-cooling airflow before transitioning
back to continuous fan 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 fan 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.
The primary continuous fan airflow (CFn) can be selected using the
3-digit display/pushbuttons or via the service tech app. Refer to the
FURNACE CONTROL PROGRAMMING AND NAVIGATION
section of this manual for instructions on adjusting the blower speed via
the control board interface. Alternate continuous fan airflows, (CF2 and
CF3), can only be modified via the service tech app.
Setting Active Continuous Fan Speed
Method 1: If the G input (or FAN switch/setting at the thermostat) is
turned OFF for 1 to 3 seconds and then back ON, the active continuous
fan speed will cycle to the next speed (CFnCF2). Repeating will
change the active continuous fan speed to the next speed (CF2CF3).
Repeating again will set the active continuous fan back to the primary
speed (CFn). This method is intended as a way for home owners to
adjust the continuous fan speed setting from the thermostat depending on
their needs.
Method 2: The active continuous fan speed (CFn, CF2 or CF3) can be
selected via the service tech app.
6. Heat pump
See Fig. 39 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/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 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/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 fan airflow.
Wiring Diagram
Refer to Fig. 61 for wiring diagram.
Troubleshooting
Refer to the service label (see Fig. 60). The Troubleshooting Guide (see
Fig. 72) 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.
To Next Page
Loading...
