the 143-16-021-08 spring typically handles a 3 to 5 psi outlet range

it is not polarity sensitive

the assembly includes a 3/8" NPT high pressure connection

ensuring the underlying cause of the safety shutdown is identified

this is an SPST (Single Pole Single Throw) relay

Resideo 40003916-026 Replacement Motor 320735-701 the 143-16-021-08 spring typically handlesThe Resideo 40003916 026 Replacement Motor is a heavy duty 24Vac synchronous actuator designed for the V8043E Series Zone Valves. As a direct field replacement for the legacy 40004850 001 (which featured the original metal cover assembly), this powerhead ensures seamless integration with existing hydronic heating infrastructures. Engineers and contractors rely on the 40003916 026 for its integrated SPST end switch, which provides critical signaling to