Designed for watertight oiltight pilot devices specifications

OEM Fitment: Precision-stamped aluminized steel ensures exact alignment with existing burner manifold and collector box footprints

preventing excessive stacking during peak demand periods

Simplified Mounting: Standard 8-inch probe length and integrated mounting box allow for quick installation on sheet metal ductwork

The control immediately initiates the igniter heat-up period upon a call for heat once safety limits are verified

Caleffi ZVR103 Relay 320788-704 Designed for watertight oiltight pilotThe Caleffi ZVR103 is a high performance 3 zone valve relay designed for professional contractors managing multi zone hydronic heating systems. Engineered for seamless integration, the ZVR103 serves as a direct technical replacement for the HPZC103, providing a robust interface between low voltage 2, 3, and 4 wire thermostats and boiler equipment. This hydronic zone valve controller features a standard 40 VA transformer, which is field expandable to