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

Does this unit require a crankcase heater

The 61-103-01 has a flow coefficient (Cv) of 1

or the unit tripping the internal thermal overload protector

McDonnell & Miller FS4-3S Switch 320720-756 Replacing it with an automaticThe 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