also known by its identical counterpart Q90DD-1C and part number J993HHW-6221

and closes tightly post-cycle to maximize thermal retention

which is specifically formulated for use with R134a systems to ensure proper lubrication and moisture control

Enhanced Sealing: The NBR diaphragm assembly provides superior resistance to typical non-corrosive fluid media

OEM Reliability: Built to original factory specifications to prevent premature tripping or mechanical failure in high-cycle applications

Lochinvar & A.O. Smith 100110820 Pressure Switch 321894-708 also known by its identicalThe Lochinvar & A. O. Smith 100110820 Pressure Switch is a critical safety component designed for high efficiency gas fired boiler and water heater systems. This 1. 42" air pressure switch (1. 42 in. WC) functions as a differential pressure switch, ensuring the combustion blower is generating sufficient airflow before allowing the ignition sequence to proceed. As a veteran technician knows, a failing HVAC pressure switch often results in a "no heat"