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Table 19. Alert Codes and Troubleshooting
GF= Gas Furnace, AH=Air Handler, ID=Indoor unit (GF or AH), HP=Heat Pump, AC=Air Conditioner, OD=Outdoor Unit (AC or HP), PA=Pure Air S, ZA=Zone system and TS=Thermostat
Alert
Code
Inverter
Flash
Code
Priority
Condition
Actual Displayed
Alert Text
Under dealer
control center >
Notifications
Component or System Operational State and Troubleshooting Tip
How to clear alert code
224
Service
Urgent
GF Low
Pressure Switch
Stuck Closed
The furnace low pressure switch is stuck closed.
• Check operation of low pressure switch to see if it is stuck closed for longer than 150 seconds
during a heat call.
• Measure operating pressure (inches w.c.).
•
Inspect vent for blockage and combustion air inducer for correct operation and restriction.
• Check for moisture in pressure switch.
NOTE:
Check Service Manual and Service and Application Note H-13-07 “Condensing Furnace
Pressure Switch Troubleshooting” for additional information.
Other possible issues that are specific to the older Lennox communicating thermostats are as
follows:
It has been determined that this alert code is generated when a subsequent heating call occurs
within 30 seconds of a prior call for heat ending. If a call for heat occurs during this time period,
the inducer post-purge from the previous call may still be in process. If that condition exists, the
IFC will sense the pressure switch circuit is closed therefore activating the alert code 224 and
generate an email notification. Once the fault is cleared, typically seconds after being generated,
the subsequent call for heat will be initiated and the furnace will return to normal operation.
Lennox has not received any complaints of no heat situations associated with this operating
condition. It has been determined that occasionally the fault clears itself and the alert code is not
stored in the IFC or Lennox communicating thermostat.
Automatically clears after the issue is
corrected.
225
Service Soon
GF High
Pressure Switch
Failed to Close
The furnace high pressure switch will not close.
• Check pressure (inches w.c.) of high pressure switch closing during a heat call.
• Measure operating pressure (inches w.c.).
•
Inspect vent for blockage and combustion air inducer for correct operation and restriction.
• Check for blocked cold end heater box or condensate drain or drain strainers at outlet of the cold end heater box.
• Check cracked hoses
•
Check levelness of unit.
NOTE:
Check Service Manual and Service and Application Note H-13-07 “Condensing Furnace Pressure Switch Troubleshooting” for
additional information.
226
Service
Urgent
GF High
Pressure Switch
Stuck Closed
The furnace high pressure switch will not open.
• Check operation of high pressure switch closing during a heat call.
• Measure operating pressure (inches w.c.).
•
Inspect vent for blockage and combustion air inducer for correct operation and restriction.
• Check for moisture in pressure switch.
NOTE:
Check Service Manual and Service and Application Note H-13-07 “Condensing Furnace
Pressure Switch Troubleshooting” for additional information.
Automatically clears after the issue is
corrected.
