If the main valve fails to close tightly or exhibits erratic pressure regulation

The LP side operates within a regulation range of -0

ensuring the auxiliary heat is correctly engaged while the outdoor unit clears its coils

significantly extending the service life of bearings and seals

Enhanced Safety: The internal relief valve protected by a 1" NPT vent and stainless steel screen prevents overpressure conditions

Armstrong Fluid Technology AS1270-380 O-Ring 328140-751 If the main valve failsThe Armstrong Fluid Technology AS1270 380 O Ring is a precision engineered EPDM rubber seal designed specifically for 10 inch pump side connection suction guides. Featuring a 11. 475" ID x 0. 210" CS configuration, this EPDM cover O ring ensures a high integrity, leak proof seal within demanding HVAC pumping systems. Engineered for dimensional stability, this Armstrong pump replacement part maintains its physical properties across varying temperature