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COMPONENT FUNCTIONS
Comfort Alert™ Diagnostics
The Comfort Alert diagnostics module troubleshoots
heat pump and air conditioning system failures and
accurately detects the cause of electrical and system
related failures without any sensors. A flashing LED
indicator communicates the ALERT code to quickly direct
the technician to the root cause of a problem.
Flame Roll-Out Control
The flame roll-out control acts to verify that the burner
flame is being drawn into the heat exchanger tubes. If the
burner flame is not being drawn into the heat exchanger
tubes, the roll-out control will open within several seconds
and the integrated control diagnostic light will flash one
time. The circulating air blower and combustion blower
will continue to operate if the flame roll-out control opens.
Flame Sensor
The flame sensor acts to prove that flame has carried
over from the ignitor to the right-most burner. If no flame
is sensed, the unit will be shut down automatically.
Gas Valve
The gas valve acts to control the flow of gas to the burners
in both low and high fire. When the gas valve is energized
it automatically opens and regulates the gas pressure in
the manifold.
Pressure Switch
The pressure switch acts to verify that the inducer motor is
drawing the combustion gases through the heat exchanger
tubes and venting the gases through the vent system.
Over-Temperature Limit Control
The over-temperature limit control acts to prevent the air
temperature leaving the unit from exceeding the maximum
outlet air temperature. If the limit opens, the integrated
control diagnostic will flash one time. The circulating air
blower and combustion blower will continue to operate if
the over-temperature limit control opens.
TROUBLESHOOTING
If the unit does not operate in the cooling mode, check
the following:
• The thermostat is operating properly
• Electrical power to the unit is turned on
• The filters are not dirty
• The service doors are in place
• The 3 amp fuse is operational
• The anti-short cycle timer’s 5-minute cycle has
finished (single phase units)
If the unit does not operate in the heating mode, check
the following:
• The thermostat is operating properly
• Electrical power to the unit is turned on
• The filters are not dirty
• The gas is turned on and the manual shut-off valve
is open
• The service doors are in place
• The flame roll-out control is closed
• Refer to the diagnostic code table on the wiring
diagram or see Table 8
• The 5 amp fuse is operational
Table 8. Diagnostic Codes
STATUS LIGHT
(Red LED)
FAULT CONDITION
On
Power On
1 Flash
Limit Circuit Open
2 Flashes
Pressure Switch Stuck Open
3 Flashes
Pressure Switch Stuck Closed
4 Flashes
Ignition Failure (Check Ground)
5 Flashes
230 VAC & Neutral Reversed or
no ground
Continuous Flash
False Flame or Gas Relay Shorted
Off
Power Off
STATUS LIGHT
(Yellow LED)
FAULT CONDITION
Continuous Flash
Low Flame Sensor Signal
On
Flame Present
9. Carefully remove the burner assembly from the furnace.
DO NOT DAMAGE THE IGNITER WHILE REMOVING
THE BURNER ASSEMBLY.
10. Inspect the burners for accumulated dust or debris.
If necessary carefully clean them with a soft wire
brush and a vacuum cleaner.
DO NOT DAMAGE THE
IGNITER WHILE CLEANING THE BURNER.
11. Replace all the parts in reverse order from which they
were removed.
12. Follow the lighting instructions found on the lower unit
door to return the unit to operation.
13. Verify proper operation after servicing.
