If the compressor won't engage despite the thermostat calling for cooling

Balanced Valve Design: The pressure-relieved bellows ensure the opening degree remains consistent regardless of differential pressure changes across the 3/4" orifice

This part is standard in many Copper-Fin and early-model commercial water heaters

OEM Compatibility: Direct-fit replacement part for a wide range of Carrier HVAC units

Rugged Construction: Equipped with a stainless steel bulb and capillary to resist corrosion and mechanical wear in high-heat zones

Lochinvar & A.O. Smith 100277758 Impeller 320788-704 If the compressor won't engageThe Lochinvar & A. O. Smith 100277758 Impeller is a precision engineered 4. 75 inch plastic component designed for high efficiency hydraulic systems. As the 100277758 direct replacement for 100133559, this part ensures seamless compatibility with Lochinvar boiler pump systems and A. O. Smith water heaters. For technicians servicing high efficiency fire tube boilers or commercial water heaters, maintaining proper fluid velocity is critical for heat