J801X Installation Manual

29
TROUBLESHOOTING
If the furnace fails to operate check the following:
• Is the thermostat operating properly?
• Are the blower compartment door(s) in place?
• Is the furnace disconnect closed?
• Has the circuit breaker tripped or the control board fuse
burned open?
• Is the gas turned on?
• Are any manual reset switches open?
• Is the filter dirty or plugged?
• Is the flame sensor coated? (Remove and clean with steel
wool).
• Are all the LED’s on the furnace control board constantly
ON? If not, refer to Table 11 or the wiring diagram (Figure
19, (page 24) and Figure 20, (page 25)) to determine
fault condition.
IMPORTANT NOTE: The furnace will lock out after 5 failed
attempts for ignition and will try again every hour if the
call for heat remains.
• If the inducer blower is operating and items above have
been verified, check the blower limit switch and reset if
necessary. See Figure 21, (page 30) for component
location.
• If the furnace operates when the blower limit switch is reset,
contact a qualified service technician to identify and repair
the problem.
• If the furnace still doesn’t operate, check the flame roll-out
switch and reset if necessary. See Figure 21 for component
location.
• If the furnace operates when the flame rollout switch is
reset, contact a qualified service technician to identify and
repair the problem.
DIAGNOSTIC DESCRIPTION GREEN LED RED LED
Control Fault (No Power) Off Off
L1/Neutral Polarity Fault Flash Flash
1 Hour Lockout Alternating Flash
Normal Operation On On
Pressure Switch Closed Fault On Flash
Pressure Switch Open Fault Flash On
Open Limit Switch Fault Flash Off
Motor Fault On Off
DIAGNOSTIC DESCRIPTION YELLOW LED
Low Flame Sensor Signal Continuous Flash
Flame Present On
Table 9. Control Board Fault Conditions
FURNACE COMPONENTS
The descriptions below are various functional components
that affect the operation and shutting down of this furnace.
Some of these components and their locations are shown
in Figure 21, (page 30). If any component of the furnace
must be replaced, use only factory authorized replacement
parts specified in the Replacement Parts List provided online.
Blower Limit Switch - Prevents operation when blower is
not operational.
Flame Sensor - Verifies when a flame has carried over from
the igniter to the opposite end burner. If no flame is detected,
the furnace will shut down within 4 seconds.
Flame Roll-Out Switch - Verifies that the burner flames are
drawn into the heat exchanger tubes. If the burner flames are
not properly drawn into the heat exchanger, the flame roll-out
switch will close the gas valve and initiate the shutdown cycle.
Gas Valve - Controls the flow of gas to the burners. When the
gas valve is energized it automatically opens and regulates
the gas pressure in the manifold.
Inducer Assembly - Vents products of combustion to the
outside.
Pressure Switch - Verifies that the inducer is drawing
the combustion gases through the heat exchanger. The
pressure switch prevents furnace operation with excessive
flue blockage or improper inducer operation.
Supply Air Limit Switch - Prevents the air temperature
leaving the furnace from exceeding the maximum allowable
outlet air temperature.