What are these relays doing on my boiler?

Old 04-30-18, 02:20 PM
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What are these relays doing on my boiler?

Trying to figure out how to install a Smart Thermostat on a 30 year old Peerless boiler with 2-wire Thermostat cables. I bought a Fast-stat to generate the C wire, but they can't help me figure out how to wire it in because of the apparently unusual wiring on my system.

It's a 5 zone system, with Taco zone valves. Each zone valve goes back to a Honeywell R8222 relay, which then hooks into one of three 24V transformers (see attached photos).

What is the purpose of these relays? Normally, the Fast-stat is wired as shown on p.9 (Diagram "CM-L"), but with the relay, no one can figure out how to wire it.

Any ideas?

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Old 04-30-18, 02:54 PM
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If you could post a pic of the wiring diagram to photobucket we can get a closer look at it.
Old 04-30-18, 03:04 PM
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Photobucket doesn't allow thired party hosting anymore.

That wiring is a mess. I'm trying to figure out if the relays are used to control the valves.

Your C wire is right there.
You need to tell us which zone valve the smart stat will go on.

We'll need to confirm the red and white connections from the stat to the valve.
It looks like the stat white is connected to #1 on the valve. Confirm that.
That would mean all the red wires from the stat are connected together. Confirm that.
Looks like three transformers. You'll need to find the one that the required zone valve is connected to.

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