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PG95ESU: Installation, Start-up, Operating and Service Maintenance Instructions
9. Remove the middle unused rubber plug from the port on the
collector box opposite the condensate trap.
10. Repeat Steps 5 through 8.
11. If a condensate pump is used, check with pump manufacturer to
verify pump is safe for use with antifreeze used. Allow pump to
start and pump anti-freeze to open drain.
12. Replace main door.
13. When furnace is re-started, flush condensate pump with clear water
to check for proper operation before re-starting furnace.
Propylene glycol need not be removed before re-starting furnace.
SEQUENCE OF OPERATION
NOTE: Furnace control must be grounded for proper operation of
furnace control and flame sensing electrode. Control is grounded
through green/yellow wire routed to gas valve and burner box screw.
Using the schematic diagram in
operation through the different modes. Read and follow the wiring
diagram very carefully.
NOTE: If a power interruption occurs during a call for heat W, the
control will start a 90-second blower-only ON period two seconds after
power is restored, if the thermostat is still calling for gas heating. The
LED light will flash
12
during the 90-second period, after which the
LED will
ON
continuous, as long as no faults are detected. After the
90-second blower-on period, the furnace will respond to the thermostat
normally.
NOTE: If BTS happens to be open as well, the inducer will operate
during the 90s. If the BTS does not reset during this time, a permanent
lockout will result and power must be cycled to reset. Check BTS and
fault code
26
for more information.
The blower door must be installed for power to be conducted through the
blower door interlock switch ILK to the furnace control CPU,
transformer TRAN, inducer motor IDM, blower motor BLWM,
hot-surface igniter HSI, and gas valve GV.
Sequence of Operation - Heating
1. Call for Heat:
The wall thermostat "calls for heat", closing the R
furnace control performs a self-check, verifies the transducer reads
no pressure present, and starts the inducer motor IDM ramp to
prepurge
a. Inducer Prepurge Period: The furnace control CPU ramps up
the inducer motor IDM to prepurge pressure then the furnace
control CPU begins a 15-second prepurge period. If the
transducer fails to reach target pressure the inducer motor IDM
will remain running until target pressure is maintained.
b. Igniter Warm-Up: At the end of the prepurge period, the
Hot-Surface Igniter HSI is energized for a 17-second igniter
warm-up period. Inducer maintains pressure during igniter
warm-up or 5 minutes has elapsed. Retry after 15 minutes.
c. Trial for Ignition: When the igniter warm-up period is
completed the main gas valve relay contact GVR closes to
energize the gas valve solenoid GV. The gas valve solenoid GV
permits gas flow to the burners where it is ignited by the HSI.
Five seconds after the GVR closes, a 2-second flame proving
period begins. The HSI igniter will remain energized until the
flame is sensed or until the 2-second flame proving period
begins.
d. Flame Proving: When the burner flame is proved at the flame
sensor electrode FSE, the inducer motor IDM will increase speed
(after a short delay of 14 seconds on some modes) to a higher
RUN pressure. The control will maintain this pressure once
reached, and the furnace control CPU will begin the blower-ON
delay period while continuing to hold the gas valve GV open. If
the burner flame is not proved within the 2-second flame proving
period, the control CPU will open the gas valve relay GVR,
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
Fig.
67, follow the sequence of
W circuit. The
-
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
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
56
G and
Y circuit for cooling. The R
-
-
11) is based on the motor wire lead selection
Fig.
67)
Fig.
67). Terminal EAC-1 is
G circuit is opened, the blower motor
-
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
-
Y
-
G and
Y
-
-
G and
-
W circuit is
-
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