Front Diagnostic Lights|Switchable Priority|Simplified Wiring|Built-in Priority Protection|Compact Design|Fuse Protected|100% Factory Tested|Isolated End Switch|Contractor Friendly PC Board Layout|Universal Thermostat Compatibility|24 Volt Power Output for hard wired thermostats|Field Replaceable Transformer|Add-on Power Control Plug|Built-in, Post Purge and Pump Exercise Functions|Switchable Primary Circulator Output|Two boiler contacts, utilizes full functionality of Mod-Con boilers|Interface with -EXP Zone Valve Controls
Taco, SR504-EXP-4, Switching Relay, 4 Zone with Priority, Series: SR, 120 V, 20 A, 1/3 hp Power, 60 Hz Frequency, 24 V Coil, Screw Hole Mounting, 240 deg F, 7 in H x 10-1/4 in W x 2-3/4 in D Dimensions