Trane furnaces use a two-digit code system to indicate an error. These codes can be found on the furnace's control panel and can usually be cleared by turning the system off and then back on again.
Here's a table of some common Trane furnace error codes, their light patterns, meanings and potential issues:
|Red light constant ON
|Control panel issue
|Red light constant OFF
|Flame failure (retries exceeded)
|Gas supply issue, flame rod not sensing flame, wiring issue, etc.
|Pressure switch problem
|Blockage in vent, condensate drain plugged, etc.
|Temperature switch problem / Over temperature limit logged
|Plugged filter, plugged secondary heat exchanger, ductwork issue, etc.
Flame sensed when no flame should be present
|Leaky gas valve, stuck gas valve, defective flame sensor, etc.
|115 VAC power reversed polarity, poor grounding
|Issue with line voltage polarity or wiring, etc.
|Gas valve circuit error
|Gas valve issue
|Low flame sense signal
|Flame sensor malfunction, low gas pressure, etc.