J952V Installation Manual

40
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. Do not use emery cloth or sandpaper!)
• Are all the LED’s on the furnace and motor control boards
constantly ON? If not, refer to
Table 12 & Table 13 or the
wiring diagrams: (
Figure 29 (page 32)) 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 36 (page 41).
• If the furnace operates when the Blower Limit 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 12. Furnace Control Board Fault Conditions
DIAGNOSTIC
DESCRIPTION
GREEN
LED
RED
LED
Variable
Speed
Furnaces
Control Fault (No Power) Off Off
Normal Operation On On
Motor Fault On Flash
Communications Fault Flash Flash
Table 13. Motor Control Board Fault Conditions
• If the furnace still doesn’t operate, check the Flame Roll-
out Switches (
Figure 36) and reset if necessary.
• If the furnace operates when the Flame Rollout Switch is
reset, contact a qualified service technician to identify and
repair the problem.
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 36 (page 41). 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.
Condensate Drain Switch - The Condensate Drain Switch
will shut down the furnace if the condensate drain from the
Collector Pan becomes clogged.
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 Switches - Verifies that the inducer is drawing
the combustion gases through the heat exchanger. The
pressure switch prevents furnace operation with excessive
flue / condensate blockage or improper inducer operation.
Supply Air Limit Switch - Prevents the air temperature
leaving the furnace from exceeding the maximum allowable
outlet air temperature.