Zonefirst ZDB-16X24 16HX24W Parallel 24V 2-Pos S/R Els PW 17895 1-5/8" refers to the Outside

1-5/8" refers to the Outside Diameter (OD)

This specific model is designed strictly for hot water heating and supply systems

This part is a critical component for maintaining burner sequencing and preventing nuisance lockout codes in compatible forced-air furnaces

This control is the direct Fenwal 35-655500-001 replacement for legacy models 35-655520-001

or an "Open Pressure Switch" fault code on the furnace LED diagnostic board

Zonefirst ZDB-16X24 16HX24W Parallel 24V 2-Pos S/R Els PW 17895 1-5/8" refers to the OutsideThe Zonefirst ZDB 16X24 is a professional grade 16 inch high by 24 inch wide rectangular zone damper engineered for high performance HVAC airflow management. Operating on a 24V motor, this 2 position spring return unit provides a reliable fail safe, ensuring the damper returns to its normal state during power loss. The parallel blade damper configuration allows for rapid response times and consistent modulation, making it an essential component for