Lennox Furnace Error Code 2+6

Code 2+6 on a Lennox furnace means the high fire pressure switch was detected in the closed position before the combustion air inducer was activated. This is a safety fault because the pressure switch should only close after the inducer starts and builds adequate draft. The furnace shuts down the ignition sequence to prevent unsafe operation until the underlying cause is resolved.

No. The furnace will typically refuse to complete a heating cycle when this code is active, which is intentional. The pressure switch system is a safety control that helps ensure combustion gases are properly vented. Operating the furnace while bypassing or ignoring this fault could result in incomplete combustion or improper venting, which poses a safety risk. The fault should be diagnosed and corrected before resuming normal operation.

Repair costs depend on the root cause. Clearing a blocked or moisture-filled pressure sensing tube may only involve a service call fee, typically in the range of $75 to $150. Replacing a faulty pressure switch generally costs between $100 and $250 including parts and labor. If the inducer motor or assembly requires replacement, costs can range from $300 to $700 or more depending on the specific model and local labor rates.

Some causes, such as moisture or a visible kink in the pressure switch tubing, can be addressed by a knowledgeable DIYer after powering down the furnace. However, testing pressure switch continuity, diagnosing inducer performance, and evaluating flue obstructions often require basic electrical test equipment and familiarity with furnace components. If you are not comfortable working inside the furnace cabinet or using a multimeter, it is best to contact a qualified HVAC technician.

A power reset may temporarily clear the fault display, but if the underlying cause remains, the code will return at the next heating call or shortly after startup. The high fire pressure switch will be re-evaluated each time the furnace attempts to start, and if it is still reading closed before inducer activation, the fault will be triggered again. A reset is only a useful first step to confirm whether the fault is intermittent or consistent.