Lennox Furnace Error Code E223

E223 means the high pressure switch failed to close during a heat call. This switch is part of the inducer and venting safety circuit and must detect adequate pressure from the combustion air inducer before the furnace is allowed to ignite. When the switch stays open instead of closing, the control board locks out the heating cycle and displays E223. The cause can range from a venting restriction to a faulty inducer motor or a defective switch.

No. When E223 is active, the furnace has locked out and will not ignite, which means the system is already preventing operation as a safety measure. You should not attempt to bypass or override the lockout. The error indicates a fault in the venting or pressure sensing circuit, and running the furnace without resolving it could create unsafe combustion or venting conditions. Leave the furnace off and have it inspected before restoring operation.

Repair costs vary widely depending on the cause. Clearing a blocked vent or drain line may cost between $75 and $200 for a service call and labor. Replacing a high pressure switch typically runs between $100 and $300 including parts and labor. Replacing a combustion air inducer motor is more involved, with costs generally ranging from $300 to $700 or more depending on the motor and labor rates in your area.

Some of the simpler causes, such as clearing a blocked vent termination, reconnecting a loose pressure tube, or clearing a clogged condensate drain, are tasks a capable DIYer can handle safely. However, measuring inches of water column pressure at the switch, evaluating inducer motor performance, and replacing components like the pressure switch or inducer motor are best handled by a qualified HVAC technician. Attempting repairs without proper tools or knowledge of combustion systems carries safety risks.

A manual reset may temporarily clear the fault and allow the furnace to attempt another heat cycle, but if the underlying cause has not been corrected, the E223 error will return. Repeated resets without addressing the root cause can sometimes worsen component wear, particularly on the inducer motor. A reset is only useful as part of diagnostics, not as a long-term solution.