Trane Furnace Error Code 6

A code 6 on a Trane furnace means the 1st stage pressure switch opened five times within one operating cycle, which caused the control board to initiate a one-hour lockout. The pressure switch monitors draft airflow created by the inducer motor, and repeated dropout indicates a persistent problem with draft pressure, the switch itself, or connected components. The furnace will attempt to restart automatically after 60 minutes, but the fault will recur unless the underlying cause is corrected.

The one-hour lockout is a built-in safety feature, and the furnace will not fire while the lockout is active. The fault itself relates to draft pressure and airflow monitoring, which are part of the furnace's combustion safety system. It is best not to attempt bypassing the lockout, and the cause should be diagnosed before the furnace is returned to normal operation.

A 3-flash fault indicates that the 1st stage pressure switch has opened during a single ignition attempt, which may be caused by a transient issue or a developing problem. A code 6 fault means the same pressure switch failure occurred five times within one cycle, signaling a more persistent issue that has now triggered a protective one-hour lockout. Both faults point to the same components and use the same diagnostic approach, but a code 6 indicates the problem is consistent enough that the control board has determined a cooldown period is necessary.

The furnace will automatically exit the one-hour lockout and attempt to restart on its own, so a manual reset is not required. However, resetting the furnace early by cycling the power will not fix the root cause. If the problem with the pressure switch circuit is not resolved, the furnace will repeat the same fault sequence and lock out again.

Repair costs vary depending on the cause. Simple fixes like clearing a blocked condensate drain or replacing a cracked pressure switch hose typically cost between $75 and $200 for a service call. A faulty pressure switch replacement generally runs between $100 and $300 including parts and labor. Inducer motor replacement is more expensive, typically ranging from $300 to $700 or more depending on the model.