These UNIVERSAL single-zone switching relays will restore intermediate line- and
low-voltage switching in almost all oil-fired or gas-fired hydronic heating systems
you’re likely to meet.

Fast installation
Three knock-outs at the bottom and one at the top give you plenty of mounting and
wiring options. Large, easy-to-drive screws and the same familiar layout of
Honeywell’s classic hydronic relays, keep installation time to a minimum.

Easy service
Plug-in replaceable relays, a replaceable transformer fuse and that familiar Honeywell
layout combine to cut down on service time.

Streamlined troubleshooting
Two troubleshooting LEDs and a push-to- test button make troubleshooting as quick
as can be. The HEAT CALL LED lights upon a call for heat or when the TEST button is
pressed, and the RELAY LED lights when 120 Vac is present at the N.O. terminal.

Longer life
Compact DC relay technology means that coils run cooler and more efficiently. And
the Powerpile® rated contacts run at a lower current to eliminate possible blocked
signals due to normal contact resistance. That means fewer problems to troubleshoot,
plus longer system life for your customers. 

Flexible applications
These single-zone relays can easily be configured into multizone applications. And when powered from a 24 Vac external source, they can provide electrical isolation in low-voltage circuits.

High-current model
For higher-current or spot switching applications, the RA889A single-zone hydronic switching relay replaces any single-zone switching relays not replaceable by the lower-current R8845U model.

Large screws, plug-in relays, LED lights, and test button make these the friendliest single-zone hydronic relays on your truck. R8845U shown; use RA889A relay for higher-current applications.

Single-zone hydronic switches: