Lennox Equipment not specified Error Code 224

Priority condition: Service Urgent 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.