McDonnell & Miller 310462 Switch Assembly Els PW 29614 verify the vacuum tubing is

verify the vacuum tubing is clear of debris and the venting system is unobstructed

This is the control board only

Flexible Logic: Supports both direct and inverse acting configurations to handle various tank fill or drain requirements

specific models equipped with vent limiters must be installed in an upright/horizontal position only to ensure the limiting device functions correctly according to manufacturer specifications

eliminating the flame rollout or ignition sequence issues often associated with generic aftermarket controls

McDonnell & Miller 310462 Switch Assembly Els PW 29614 verify the vacuum tubing isThe McDonnell & Miller 310462 (Model SWA 150S) is a heavy duty snap action switch assembly designed for precise low water cut off and pump controller transitions. This automatic reset assembly is a critical replacement component for Series 150S and Series 157S mechanical boiler controls. Built to manage steam boiler water levels up to a maximum operating pressure of 150 psi, the SWA150S provides reliable SPDT switching to prevent dry fire conditions