This is an auto-reset limit switch

This specific part is engineered for horizontal mounting

Simplifies repairs by replacing superseded legacy part number D49766-82

the 63922 burner orifice provides the exact physical dimensions and sizing required for seamless integration with Reznor F-50 and F-75 models

meeting the original factory specifications for system safety and operational reliability in commercial and residential hydronic applications

Johnson Controls T-4000-3139 Plastic Cover This is an auto-reset limitThe Johnson Controls T 4000 3139 is a professional grade horizontal pneumatic thermostat cover designed specifically for the T 4000 Series room thermostats. Engineered for demanding commercial environments, this white plastic cover provides a clean, uniform look for horizontal mounted controllers where a blank faceplate cover is required. As a genuine Johnson Controls replacement part, it ensures a precise fit for single or dual element sensing units