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Rick, HVAC Supervisor
Category: HVAC
Satisfied Customers: 21393
Experience:  40+ yrs. experience as a licensed oil & gas technician.
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Looking diagram using a Ribuic relay,a 3 wire taco zone

Customer Question

Looking for wire diagram using a Ribuic relay,a 3 wire taco zone valve and programmable t stat w/batteries with the wires going back to a Wm97 gas boiler
Submitted: 1 year ago.
Category: HVAC
Expert:  Rick replied 1 year ago.

What do you need the relay for?

Customer: replied 1 year ago.
The boiler Manual says I need isolation relays for 3 wire taco zone valves so I don't get stray voltage
Expert:  Rick replied 1 year ago.

Do you have a model number for the relay?

Expert:  Rick replied 1 year ago.

If you mean an RIBU1C, that's not a suitable relay. You need a Taco SR501 or similar.

Customer: replied 1 year ago.
Okay, can you still give me a wiring diagram please showing how it will all work
Expert:  Rick replied 1 year ago.

There is no diagram unless I draw one but it's pretty simple. Here is the diagram for the SR501
You connect your Taco zone valve end switch leads (2 & 3) to R & W on the relay. Line voltage to N & H (as shown) 5 & 6 N/O to the thermostat terminal on the low voltage terminal strip on the WM97 corresponding to the line voltage zone you have the system pump wired to. If you have more than 1 zone valve all the valve end switch leads go to R & W on the SR501,

Customer: replied 1 year ago.
Thanks Rick, The WM boiler manual says to use isolation relays.the boiler has low voltage wiring terminal board built in already for up to 3 zones.I have a run a 3 wire cable out to each zone valve from boiler , then 2 wire up to there a drawing I could see using a isolation relay
Expert:  Rick replied 1 year ago.

Like I said there is no drawing and what I just described to you is how you use an SR501 as an isolation relay. Check the Taco link in my last reply if you don't know how to wire the zone valves.

Customer: replied 1 year ago.
Rick, I understand how to wire the zone valve. Dont want to have to spend more money on a control board from Taco when my new boiler already has one.was just hoping to see something that incorporated iso relays into the mix without the added expense!
Expert:  Rick replied 1 year ago.

You have to buy a relay. The pump relays in the boiler perform an entirely different function. The relay that's most commonly available and is suitable for this purpose is the SR501. The relay you mentioned initially is not suitable it's not a switching relay. I'm not aware of any switching relays for less money than an SR501 (~$45)