Does this unit require a crankcase heater

ensuring HVAC pilot assembly compatibility across major commercial burner platforms

Replacing it with an automatic reset switch would bypass a critical safety protocol and create a hazardous condition if the underlying venting issue persists

allowing for sequenced control with other pneumatic devices

McDonnell & Miller FS4-3S Switch 320720-756 Does this unit require aThe McDonnell & Miller FS4 3S (Part Number 114641) is a rugged general purpose liquid flow switch specifically engineered for high demand hydronic and industrial applications. This 1" NPT flow switch features a high grade stainless steel body and hardened stainless steel bearings to minimize friction and prevent mechanical failure in the field. Designed as the direct replacement for FS4 3S E, it integrates a Single Pole Double Throw (SPDT) snap switch