2-Zone Switching Relay w/ Priority


Brand: Taco

Mfr Part#: SR502-4

UPC#: 687752857559

Availability: In Stock
Usually ships: within 1 business day
Qty Price
$120.95 / each & Free Shipping
x3 $347.85 & Free Shipping
(3 x $115.95 / each)
  • Description
  • Literature
  • Reviews
  • FAQs (2)

Taco SR502 Switching Relay combines clearly labeled PC board layout with advanced features that allow for total system customization. External indicator lights provide instant diagnostic feedback, making a snap of service calls or new installation start-ups. Taco SR502 switching relays are UL and CSA listed, use standard “ice cube” replaceable relays and are compatible with conventional and programmable thermostats.


  • External Indicator Lights;
  • Switchable Priority;
  • Simplified Wiring;
  • Fully Enclosed Snap-Out Relays;
  • Compact Design;
  • Fuse Protected;
  • 100% Factory Tested;
  • Isolated End Switch;
  • Contractor Friendly PC Board Layout;
  • Universal Thermostat Compatibility;
  • UL and CSA Approved;
  • 24 Volt Power Input or Output Terminal;
  • Made in the USA;

Technical Specifications:

  • Zones: 2;
  • Power: 120VAC;
  • Max combined load: 15.0 AMPs;
  • Dimensions: 10.25" wide x 6.75" high x 2.75" deep.


Extended 3 Year Warranty
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Is it possible to control a zone valve from a switching relay?
Read 1 answer
Taco SR switching relays are for circulators only. If you need to control zone valves, use Taco ZVC (Zone Valve Controls).
Answered on 12/10/2013 by PexUniverse Customer Service
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I have 4 zones of baseboard heat in my home. I installed a fifth zone which is radiant heat with its on pump, zone valve and mixing valve. I purchased a tacosr502 switching relay so that the pump can run for the radiant side when thermostat call for heat. My question is do I leave all the the existing thermostat wires connected to the TT ?
Read 1 answer
If radiant heating zone requires a separate temperature control, then a separate thermostat has to be installed and wired to the Taco SR502 panel.
Answered on 9/4/2012 by PexUniverse Customer Service
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