Once the plenum cools to the 160°F reset temperature

Unlike standard rubber seals that fail under thermal stress

With 1/4" barbed connections optimized for 3/8" OD polyethylene tubing

High Pressure Rating: Tested up to 700 psi

ensuring rapid signal response to the controller

Weil McLain 383-500-020 Inspection Glass Kit Once the plenum cools toFor high efficiency boiler maintenance, the Weil McLain 383 500 020 Inspection Glass Kit is the essential OEM solution for monitoring combustion and flame quality in Ultra Series 1 and 2 boilers. This complete assembly is critical for identifying potential burner issues or soot buildup without compromising the sealed combustion environment. As a professional grade boiler sight glass replacement, it includes the high temperature borosilicate glass, a