a fouled or oxidized HVAC flame sensor is the primary culprit behind intermittent ignition failure and short-cycling

or a complete failure of the blower to engage when the thermostat calls for air

000 BTU for natural gas

High-Pressure Ready: Specifically designed for liquid level monitoring in systems up to 500 PSI

If the contacts are welded shut

Lennox 15D33 TXV 322057-301 a fouled or oxidized HVACThe Lennox 15D33 TXV is a high performance 4 ton thermal expansion valve engineered for precise refrigerant metering in residential and light commercial cooling systems. This OEM Lennox replacement part features a 3 8" ODM inlet and a 1 2" ODF outlet, specifically designed for R 410A refrigerant applications. By accurately responding to evaporator pressure and temperature changes, the 15D33 expansion valve maintains optimal superheat, protecting your