All circulator relay connections, including ZC/ZR, are rated 1/3 hp (6 FLA, 36 LRA) at 120 VAC. The thermostat connection supplies a 24 VAC class 2 output. Problem: Digital thermostats do not work …

Taco Switching Relays combine clearly labeled PC board layouts with advanced features that allow for total system customization. Whether using basic functionality, DIP switch features or the advanced …

Dec 10, 2025 · The SR501 single zone switching relay is UL and CSA listed, uses a standard "ice cube" replaceable relay and is compatible with conventional and programmable thermostats.

Jul 18, 2021 · Learn about the PIR sensor HC SR501 with explanation of its working, pin diagram and description, dimensions, range and PIR sensor datasheet.

Boston Heating Supply has the Taco SR-501 One Zone Pump Switching Relay in stock. We also have many other products from Rheem-Ruud, Laars Teledyne, Grundfos, Taco, Takagi, Triangle Tube, …

Nov 15, 2025 · Ideal for homeowners looking for a reliable switching relay, making zoning control easier and more efficient. Ideal for oil burner systems, this relay offers integrated transformer, flame …

External indicator lights provide instant diagnostic feedback, making a snap of service calls or new installation start-ups. The SR501-HC with its high current switching capability, makes it is ideal for …

No matter what type of job, our single zone switching relay replaces every brand made by every manufacturer, and will even fit into the existing metal enclosure without rewiring incoming connections.

COM Power Input: SR 501-4 Input: on the on switching OPERATION: the switching relay.

Jul 12, 2019 · In this tutorial you will learn how the HC-SR501 sensor works and how you can use it with Arduino. Wiring diagram and example codes included!