CALEFFI ZVR103 Valve Switching Relay - 3 Zone The ZVR series is a zone valve and boiler operating control for multiple zone hydronic heating systems. The ZVR series interfaces with low voltage thermostats, or any other low voltage controllers having a switching action. LED indicators provide functional status and easy system troubleshooting. Compatible with 2, 3 and 4-wire thermostats or other low voltage controllers with switching action 120 VAC input Heavy duty, sealed relays 3 pump outputs (120 VAC/5 A) 3 zone valve outputs (24 V) Zone priority selectable with 1-hour time-out feature Convenient R,W,C and T,T,COM dual labeling at thermostat terminals System pump status (on/off) during priority selectable Dry contacts (XX,AUX, ZONE 1 E/S) capable of switching line voltage Replaceable, snap-fit 40 VA transformer Automatic resettable fuse on 24 V circuit Large screw terminals for ease of wiring. On-board ground terminals Front panel LED indicator light for functional status ETL certified to CSA and UL standards