McDonnell & Miller 354089 Switch Assembly 320734-701 While the 1/4" barb is

While the 1/4" barb is common

For heavier schedules or specialized materials like stainless steel

Commercial Grade Durability: Engineered to resist thermal fatigue in high-demand heating applications

or a slipping hub

this assembly provides superior corrosion resistance against the acidic condensate typical of high-efficiency secondary heat exchange cycles

McDonnell & Miller 354089 Switch Assembly 320734-701 While the 1/4" barb isThe McDonnell & Miller 354089 Switch Assembly, also designated as the Model SWA 150S M, is a critical replacement component engineered specifically for Series 150S and 157S low water cut offs and pump controllers. For technicians servicing steam boilers, this snap action switch assembly is the standard for maintaining precise liquid level control and ensuring high limit safety. Featuring a manual reset mechanism, this assembly requires professional