As a straight-thru-flow regulator accessory

such as a clogged MERV-rated air filter

The Marley Engineered Products 4520-2059-000 is an OEM 160-230F AUTO Limit Switch designed for high-accuracy temperature monitoring in HVAC heating systems

verify your valve body construction—threaded or solder—before attempting replacement

Smith units

MARS 12921 Run Capacitor As a straight-thru-flow regulator accessoryThe MARS 12921 Run Capacitor is a fundamental component for maintaining the efficiency of single phase electric motors in HVAC and refrigeration systems. This 40 MFD 370V oval run capacitor is engineered for continuous duty, providing the necessary phase shift to keep compressors and fan motors running cool and stable. Built to UL 810 standards, it features a non PCB, oil filled aluminum construction and a patented internal pressure sensitive