Furnace Fails to Operate Properly
Review "Sequence of Operation" and visually inspect the
following before troubleshooting:
Is the power to the furnace on?
Is the blower compartment door securely closed?
Are the manual shutoff valves in the gas line to the furnace open?
The system has a built-in, self-diagnostic capability. The control
continuously monitors its own operation and the operation of the
system. If a system problem occurs, a failure code is indicated by
the LED on the gas control valve. See the Failure Codes chart for
a description of the flash codes.
IMPORTANT: Do not remove the blower compartment door or
turn off the power to the furnace because either action will clear
the control's memory of the failure.
1. Start the system by setting the thermostat above the room
2. Observe the system's response.
3. Use the information provided in this section to check the
No Power to the System Control
Normal Operation (Standby or call for heat)
Pressure switch closed when it should be
Pressure switch stuck open 30 seconds or
longer after call for heat (system in 5-minute
delay mode before next call for heat). On/off
switch in OFF position during a call for heat
will generate this code.
Open Limit Switch or Limit Switch Circuit
Flame Sense Signal sensed out of proper
* 11 or more flashes with no pause