While technically an air pressure switch

the internal thermal disc has failed and requires replacement

Always verify the series on the regulator nameplate before installation

High-Power Relay: Rated for 20A at 240 VAC

This genuine S1-025-39887-000 replacement part ensures the system meets original manufacturer delta-T and combustion efficiency specifications

Armstrong Furnace R101432-16 Pressure Switch While technically an air pressureWhen the job requires a precise match for Armstrong Air or Allied Air heating units, the Armstrong Furnace R101432 13 Pressure Switch is the mandatory OEM replacement for ensuring safe combustion. This . 55"wc SPST pressure switch is engineered to monitor the negative pressure generated by the inducer motor, verifying a clear flue and adequate draft before the ignition sequence begins. Featuring dual 1 4" barb connections, this switch provides a