18-CD37D1-2-EN
43
Installer’s Guide
INSTRUCTIONS TO THE OWNERS
▲
WARNING
!
EXPLOSION HAZARD
IN THE EVENT THAT ELECTRICAL, FUEL OR
MECHANICAL FAILURES OCCUR, SHUT OFF THE
GAS SUPPLY AT THE MANUAL GAS SHUT OFF VALVE,
LOCATED ON THE SUPPLY GAS PIPING COMING
INTO THE FURNACE, BEFORE TURNING OFF THE
ELECTRICAL POWER TO THE FURNACE. CONTACT
SERVICER.
FAILURE TO FOLLOW THIS WARNING COULD RESULT
IN PROPERTY DAMAGE, PERSONAL INJURY OR
DEATH.
BURNER BOX TEMPERATURE LIMIT DEVICE
All models are equipped with a manual reset temperature limit
located on the Burner Box. In case of excessive temperature,
the limit will open and cause the circuit to open which shuts off
all flow of gas.
CONDITIONS THAT AFFECT SYSTEM
OPERATION
1. EXCESSIVE COMBUSTION PRESSURE (WIND IN
EXCESS OF 40 M.P.H.) VENT OR FLUE BLOCKAGE
On a call for heat, the Variable Speed Draft Inducer must
first ramp up to speed and close the Pressure Switch
before the ignition sequence is allowed to begin. If the
Pressure Switch does not close, the motor will ramp up to
maximum speed and continue to operate there for about
1 minute.
After one minute, the Integrated Furnace Control will turn
the motor off for about 30 seconds and then back on in
an attempt to reestablish proper operation. This condition
is indicative of a highly restricted or blocked inlet or outlet
vent pipe or a failed Pressure Switch.
If pressure against induced draft blower outlet becomes
excessive, the Pressure Switch will open. If the Pressure
Switch is open for more than 3.5 seconds, the variable
speed draft inducer will speed up and attempt to close
the Pressure Switch. If the Pressure Switch is not closed
within 12 seconds or if the maximum speed of the motor
is reached, the draft inducer sends a Fault signal to the
Integrated Furnace Control. If the unit is operating in
Second Stage, an Inducer Fault will cause the Furnace
Control to transition the system to First Stage and it will
operate there for 10 minutes before attempting to run
again in Second Stage. If the unit is operating in First
Stage, an Inducer Fault will cause the Furnace Control
to shut the system down and wait 30 seconds before
attempting to reestablish operation in First Stage.
2. LOSS OF FLAME
If loss of flame occurs during a heating cycle, or flame is
not present at the sensor, the flame control module will
close the Gas Valve. The Integrated Furnace Control will
then recycle the ignition sequence, then if ignition is not
achieved, it will shut off the Gas Valve and lock out the
system.
3. POWER FAILURE
If there is a power failure during a heating cycle, the
system will restart the ignition sequence automatically
when power is restored, if the Comfort Control still calls
for heat.
4. GAS SUPPLY FAILURE
If loss of flame occurs during a heating cycle, the
system Integrated Control Module will recycle the ignition
sequence, then if ignition is not achieved, the Integrated
Control Module will shut off the Gas Valve and lock out the
system.
5. INDUCED DRAFT BLOWER FAILURE
Please refer to the Variable Speed Draft Inducer
troubleshooting manual for diagnostic assistance.
6. CONDENSATE DRAIN BLOCKAGE
If the condensate drain is blocked, either by debris,
improper draining, or by freezing condensate, the
pressure switch will receive a signal warning of the
accumulation of condensate in the heat exchanger
assembly. The pressure switch contacts will open and
remain open, not allowing unit operation. The unit will not
operate until the condensate drain has been cleared, and
the condensate flows freely.
7. RESET AFTER LOCKOUT
When the Integrated Furnace Control has shut the system
down and gone into lockout, the system must be manually
reset before the unit will restart. The system can be reset
by turning the system power off for more than 1 second,
or by removing 24VAC from the control for more than 1
second, or by removing the Comfort Control call for heat
for more than 1 second but less than 20 seconds.
8. RESET AFTER BURNER BOX LIMIT SHUTDOWN
If the furnace shuts down, one thing that can be checked
is the burner box temperature limit switch. It is located on
the bottom of the burner box. The vent and combustion
air inlet terminations should be checked for blockage.
If blockage exists, clear the problem and then the reset
button may be depressed.
If there is no blockage of
the terminations, the limit switch must be reset by a
qualified servicer.
INDOOR MOTOR MAINTENANCE
Direct drive motors have bearings which are permanently
lubricated and under normal use, lubrication is not
recommended.
