This L220-40F Plenum Limit Switch acts as a primary thermal protection device

This OEM replacement limit switch features an automatic reset mechanism calibrated for a 220-250F temperature range

Zero Effusion: Internal copper construction ensures refrigerant stays contained without environmental leakage

What causes these door switches to fail prematurely

The baseplate utilizes high-quality low-voltage 5mm terminals that accept 14–24 AWG solid or stranded copper wire

Watts 0274934 Valve Els PW 17895 This L220-40F Plenum Limit SwitchThe Watts 0274934, also identified as the Watts 174A 1 30, is a high capacity 1 inch ASME pressure relief valve designed specifically for hot water heating systems and domestic supply boilers. Engineered with a heavy duty bronze body and a stainless steel spring, this valve provides critical overpressure protection for equipment rated up to 1,005,000 BTU hr. The 174A series is the industry standard for contractors requiring a 30 PSI relief setting