Lennox S40 - Page 58

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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
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.
227 Service Soon
GF Low Pressure
Switch Open in Run
Mode
The furnace low pressure switch is open while in run mode.
• Check pressure (inches w.c.) of low 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 cold end heater
box.
• 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
after the issue is
corrected.
228 Service Soon
GF Inducer Calibration
Issue
The furnace control is not able to calibrate the pressure switch. Unable to perform pressure switch calibration.
• 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 cold end heater
box (CEHB).
• 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
after a successful
calibration.
229
Information
Only-Dealer
GF Ignition on High
Fire
• Furnace control switched to high re ignition because low re pressure switch did not close in allowed time.
• *Early models only, if fan is on when call for W1 is initiated; unit will re on high re for 60 seconds before
dropping down to low re.
No action is required.