Mixing 3 wire Taco Zone Valves with a Zone Sentry Valve

carlg

I have a hydronic baseboard heating system with 3 zones. They use Taco Zone valves. 2 of the zone valves are the older 3-wire versions. 1 of them is the new Zone Sentry type of valve. The new zone sentry valve has 4 wire connections. With the old valves your wire went from terminal 2(C) on one valve to terminal 2 on the next valve, to terminal 2 on the 3rd valve, intersected with 1 of the wires from the transformer and then back to the boiler control.

The new Zone Sentry valve is supposed to go from C to C to C and then back to the transformer. It does not have the boiler involved with this loop.

So if I go from terminal 2(C) on old valve to C on new valve to terminal 2(C) on another old valve, intersect with 1 transformer wire and then to boiler, will I mess something up??

If not, what is the proper way to wire up (2) 3 wire valves with a 4-wire in the same system?

Thanks!!!

Paul48

Why not use a Taco zone valve control?

carlg

Paul48 said:

Why not use a Taco zone valve control?

I guess I could, but then that's another $100 that I need to spend. Once up and running, what advantage does the control give me?

HVACNUT

What aquastat (boiler control) do you have? Is the zone valve transformer external from the aquastat?

carlg

HVACNUT said:

What aquastat (boiler control) do you have? Is the zone valve transformer external from the aquastat?

Honeywell auqustat, transformer is external.

HVACNUT

> @carlg said:

> Honeywell auqustat, transformer is external.

>> ok, honeywell, L4006A, L8124, L8148?

Zman

The taco controller just cleans everything up.
The 3 wire is, from a controls point of view, a messy way to wire boiler. Adding a 4 wire product to the deal just makes it even uglier.

With the controller, all the zones and the boiler are isolated. The LED lights tell you the status of everything.

HVACNUT

Who needs directions?
My impression of Brad Pitt in Se7en.
"What's in the box?! What's in **** the box?!"

carlg

HVACNUT said:

Who needs directions?

My impression of Brad Pitt in Se7en.

"What's in the box?! What's in **** the box?!"

I have those directions, but they don't show the wiring for a mixed set up (when you have both 3-wire and zone sentry in same set up).

HVACNUT

Sorry, I like doing impressions.

Wire from terminal 1 to W/Y on sentry.

Wire from terminal 3 to T on aquastat.

Wire from terminal 2 to C on sentry AND the other T on the aquastat.

This is if you have an L8124 or L8148.

carlg

HVACNUT said:

Sorry, I like doing impressions.



Wire from terminal 1 to W/Y on sentry.



Wire from terminal 3 to T on aquastat.



Wire from terminal 2 to C on sentry AND the other T on the aquastat.



This is if you have an L8124 or L8148.

LOL, nothing to be sorry for, you are helping me. I should be thankful. By the way thanks.

HVACNUT

> @carlg said:

> LOL, nothing to be sorry for, you are helping me. I should be thankful. By the way thanks.

>> I sent you you an IM. My directions are incomplete. Bet you're sorry now.

Joe Mattiello

I have attached a snippet of the wiring diagram available on the Zone Sentry instruction sheet. Follow the schematic and parallel the end switch terminals to facilitate wiring back to boiler TT terminals. If you're still having difficulty wiring, please contact Taco tech support at 401-942-8000 for additional support.

It’s a good idea to use a zone valve control ZVC404-4 to facilitate the wiring; there are many reasons to use a control.
Facilitate wiring, diagnostic lights for troubleshooting, and priority for DHW. The EXP version provide additional attributes, like optional outdoor reset, two boiler staging control, or injection pumping. Standard and inherent in the control are Pump exercise, priority protection, and post purge. Hopefully this helps