the switch should be normally closed (showing zero or near-zero ohms)

Industrial Durability: Built to withstand the thermal stress and high-cycle operation of commercial HVACR units

Compact & Durable: The Noryl enclosure provides moisture resistance and can be mounted in various orientations to fit tight furnace or boiler cabinets

Some Maxon detectors allow for field trimming

While this model is optimized for 1" piping

Watts 0275614 Relief Valve 326058-755 the switch should be normallyThe Watts 0275614 (Model 375XL) is a high capacity pressure relief valve designed specifically for hot water heating boilers and hydraulic systems. Featuring a 1 1 4 inch NPT threaded inlet and a 1 1 2 inch NPT outlet, this valve is factory set to a 35 PSI relief pressure, providing critical overpressure protection. Utilizing a bronze body construction and a silicone rubber disc, it ensures a tight seal and reliable reseating after discharge. For