Carrier 59SU5A Manual page 57

59SU5A: Installation, Start-up, Operating and Service Maintenance Instructions
de-energizing the gas valve solenoid GV. The control CPU will
repeat the ignition sequence for up to three more
Trials-For-Ignition before going to an Ignition-Lockout. Lockout
will be reset automatically after three hours, or by momentarily
interrupting 115 vac power to the furnace, or by interrupting 24
vac power at SEC1 or SEC2 to the furnace control CPU (not at
W, G, R, etc.). If flame is proved when flame should not be
present, the furnace control CPU will lock out of Heating mode
and operate the inducer motor IDM until flame is no longer
proved.
e. Blower-On-Delay: If the burner flame is proven a 25-second
blower-ON delay begins from when the gas valve GV is opened.
The blower motor BLWM is turned ON at heat airflow.
Simultaneously, the humidifier terminal HUM and electronic air
cleaner terminal EAC-1 are energized and remain energized
throughout the heating cycle.
f. Blower-Off-Delay: When the thermostat is satisfied, the R to W
circuit is opened, de-energizing the gas valve GV, stopping gas
flow to the burners, and de-energizing the humidifier terminal
HUM. The inducer motor IDM will remain energized for a
15-second post-purge period. The blower motor BLWM and air
cleaner terminal EAC-1 will remain energized at heat airflow for
90, 120, 150, or 180 seconds (depending 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 closes the R
circuit starts the outdoor unit on cooling speed, and the R
circuit starts the furnace blower motor BLWM at cooling airflow.
Cooling airflow (Table 11) is based on the motor wire lead selection
used on the COOL terminal. 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
Y circuit is 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. Remove J2 Jumper to
reduce the cooling off-delay to 5 seconds. (See
3. Continuous Blower Mode
When the R G circuit is closed by the thermostat, the blower motor
-
BLWM will operate at FAN tap (See
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 FAN tap. 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 HEAT tap. The blower motor
BLWM will revert to FAN tap after the heating cycle blower
off-delay is completed. When the thermostat "calls for cooling", the
blower motor BLWM will switch to operate at COOL tap. When
the thermostat is satisfied, the blower motor BLWM will operate an
additional 90 seconds at cooling airflow before transitioning back
to FAN tap. When the R
BLWM will continue operating for an additional 5 seconds, if no
other function required blower motor BLWM operation.
4. Heat Pump: 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 the R
closed along with the R
-
transition to or bring on the blower motor BLWM at COOL tap.
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 HEAT tap. When the R
furnace control begins a normal inducer post-purge period while
changing the blower airflow. If R
furnace control CPU will transition the blower motor BLWM
airflow to COOL tap. If R
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
G and Y circuit for cooling. The R
- -
Fig. 68)
Fig. 68). Terminal EAC-1 is
G circuit is opened, the blower motor
-
W circuit is
-
Y circuit, the furnace control CPU will
W connection is opened, the
-
Y circuit is still closed, the
-
G circuit is open, the blower motor
-
BLWM will remain on HEAT tap for the selected blower-OFF
delay period. At the end of the blower-OFF delay, the blower motor
BLWM will shut OFF unless R
the blower motor BLWM will operate at FAN tap.
5. Component Test: To initiate the component test sequence, shut
OFF the room thermostat or disconnect the "R" thermostat lead.
Briefly short the TEST/TWIN terminal to the "C" terminal. Status
LED will flash most recent code 4 times and then turn ON the
inducer motor.
The inducer motor will run for the entire component test. The hot
surface igniter, blower motor fan speed, blower motor-heat speed,
and blower motor-cool speed will be turned ON for 10-15 seconds
each. Gas Valve and Humidifier will not be turned on.
Wiring Diagrams
Refer to Fig. 68
Troubleshooting
Refer to the service label. (see
and the Service Guide (Page 44) can be a useful tool in isolating furnace
operation problems. The Guide will help to identify the problem or
failed component. After replacing any component, verify correct
operation sequence.
Y
-
G and Y
- -
G and
-
57
G is circuit is closed, in which case
-
for wiring diagram.
Fig. 63), wiring diagram (see Fig. 68),