Resideo AT20B1056 Transformer 321142-301 check for continuity across the

check for continuity across the pins

and PCBBF106S

It monitors both temperature and relative humidity to calculate the total heat content (enthalpy) of the air

minimizing delay from the call for heat to burner stabilization

Resideo AT20B1056 Transformer 321142-301 check for continuity across theThe Resideo AT20B1056 is a professional grade 120V to 24V step down transformer engineered for high reliability in residential and light commercial HVACR control circuits. Delivering a 20VA power rating, this unit is specifically designed to power 24VAC thermostats, zone valves, and relay coils with consistent voltage output. The channel frame mounting configuration allows for secure installation directly onto junction boxes or appliance cabinets,