Lennox furnace error code 434

This error is related to a water sensor reading as “High”.

This can be caused by not having the correct water setting on the furnace.

Another cause may be that either the sensor detector is removed or broken.

Clear condensation from the unit, close air gaps around the door that are provided for vapor circulation, then restart.

Lennox furnaces are manufactured by an American company with over 85 years of expertise in heating and cooling. The furnace’s performance relies on various sensor inputs that direct the onboard computer to behave accordingly. A customer will know if there is a problem with their furnace if the front panel beeps continuously, the display blinks, or a red light starts to flash.

There is no single Lennox furnace error code 434 because there are internal problems specific to your Lennox appliance usually represented by complex combinations of numbers and letters.

Possible reasons for this error are that there is a problem with the grid connection for the home, a trip has happened on the device’s circuit board, or that a high current has tripped when powering this device.

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