Lennox S40 - Page 61

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Table 21. Lennox S40 Smart Thermostat Alert Codes and Troubleshooting
E2A=Errors to Action, GF= Gas Furnace, AH=Air Handler, IU=Indoor unit (GF or AH), HP=Heat Pump, AC=Air Conditioner, OU=Outdoor Unit (AC or HP), PA=Pure Air S, ZA=Zone system,
SRS=Smart Room Sensor, TS=Thermostat , IAQ- IAQ Monitor and WE=Wi-Fi Extender
Alert
Code
Inverter
Flash
Code
Priority
Condition
Actual Displayed Alert
Text Under dealer control
center > Notications
Component or System Operational State and Troubleshooting Tip
How to clear
alert code
275
Service
Urgent
GF Flame Out Of Seq.
No Flame
The furnace ame is out of sequence. The system will go into Watchguard mode.
• Shut off gas.
• Check for gas valve leak.
Automatically clears on
successful ignition.
276
Service
Urgent
GF Calibration Failure
The furnace is not able to calibrate or the high pressure switch opened or failed to close in run mode. The
system will go into Watchguard mode.
• Measure operating pressure (inches w.c.).
• Inspect vent for blockages, and combustion air inducer for correct operation and restriction.
• Check for blocked cold end heater box (CEHB), or condensate drain or drain strainers at outlet of CEHB
and cracked hoses.
• Check for 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.
Automatically clears
when the furnace
calibrates itself
successfully.
290
Service
Urgent
GF Ignition Circuit
Fault
There is a problem with the furnace ignition circuit. The system will go into Watchguard mode.
Measure resistance of hot surface igniter. Replace the hot surface igniter if it is not within specications.
Automatically clears on
successful ignition
291
Service
Urgent
GF Heat Airow Below
Min
The heating airow is below the minimum required level. The system will go into Watchguard mode.
• Check for dirty air lter(s) and other air ow restrictions.
• Check blower performance.
Automatically clears
when a heat call ends
successfully.
292
Service
Urgent
ID Blower Motor Start
Fault
The indoor unit blower motor will not start. The system will go into Watchguard mode.
• Indoor blower motor unable to start.
• This could be due to seized bearing, stuck wheel, and obstructions.
• Replace motor, motor module or wheel if assembly does not operate or meet performance standards.
NOTE: Refer to Service and Application Note H-17-02 “All Communicating Variable Speed Motors”.
Automatically clears
after the indoor
blower motor starts
successfully.
294
Service
Soon/Service
Urgent
GF Inducer Motor
Overcurrent
There is over current in the furnace inducer motor. The system will go into Watchguard mode.
• Check combustion blower bearings, wiring and amps.
• Replace furnace inducer motor if it does not operate or does not meet performance standards.
Automatically clears
after inducer motor
current is sensed to
be in-range after the
ignition following either
Watchguard mode or
unit reset.