Can I wire a Taco 571 zone valve to an Argo ARM-6P switching relay

DonB5

Hi. Pretty new to this but will do my best to explain properly.


Trying to figure out if I can connect Taco 571 zone valve to Argo ARM-6P switching relay to split one zone into two. Details below.

I have hot water heat with 6 zones and 6 circulators, controlled by an Argo ARM-6P switching relay, shown below. When the house was completed, all 6 zones on the switching relay were taken (connected to thermostats). Later, when we finished our bonus room, to get heat to it the contractor put in a bonus room loop and a thermostat on that loop, and doubled that thermostat up with a thermostat for the existing upstairs loop, putting it on zone 2. You can see the two sets of wires connected to the thermostat terminals on zone 2.

The problem with this is that when either thermostat (the one for the upstairs, or the one for the bonus room) calls for heat, the burner fires and circulator #2 pumps so I get heat to both places.

I want to split it into two so that each thermostat controls only its loop. A friend and I thought, oh, we'll put a zone valve (Taco 571) on the upstairs loop, and another zone valve (also Taco 571) on the bonus room loop. Our idea was that everything would still be controlled from the terminals from zone 2:

• The upstairs loop would have a red wire run from the red zone 2 terminal connection to the upstairs thermostat, then from that thermostat to terminal #1 on the upstairs zone valve, and then back from terminal #3 on the upstairs zone valve to the white zone 2 terminal on the ARM-6P. Meanwhile, a common wire would run from terminal #2 on the Taco zone valve to the common connection on the ARM-6P. (In the upper right hand of the circuit board in the picture of the ARM-6P below, you see two terminals, white over red, white is labeled as common although you can't make that out from the picture. We'd run from terminal #2 on the Taco to the common terminal on the ARM-6P.)
  
• We'd do the same exact thing for the bonus room loop, using the ARM-6P terminal #2 connectors for the Taco #1 and #3 wires, and the ARM-6P common terminal for the Taco #2 wire.
  

I thought it made sense, but it doesn't work. It trips the transformer reset fuse on the board.

I called Argo and they said I should add an Argo AZ3 Zone Panel. It would handle the thermostats and Taco zone valves and just have a single set of wires leaving a zone panel end switch and going to the thermostat terminals on the Argo switching relay.

I'm prepared to do that, but before I do, I would like to ask: does this seem like the best solution? Is it possible instead to connect the Taco zone valves to the existing Argo ARM-6P switching relay, and not have to buy an additional control?

If it is possible to wire to the ARM-6P, can you say how I should do it, since the approach I describe above did not seem to work?

Many thanks for thoughts and advice. I knew nothing about this 2 weeks ago so I'm trying to get smarter about it.

STEVEusaPA

You should get the additional control. If one of the zones takes a dump, you can just switch the wires over to an unused zone. Plus if you have any power stealing thermostats, or add them later, the transformer on one zone panel may not do them all.

Ironman

The ARM is a 120v output PUMP control panel. You need the AZ3 panel which has 24v output for the zone valves.

EdTheHeaterMan

There is a way to do it without a separate zone valve control.  Give me a minute to draw it up for you.   Answer one Question 
Do I understand you correctly, either thermostat on the zone valves zones will operate the same #2 circulator pump?

EdTheHeaterMan

Since you are only using 2 Taco Zone Valves, then I would recommend this diagram.

The Zone valves must be powered by a separate transformer like this one. https://www.supplyhouse.com/Resideo-AT140A1000-Foot-Mounted-Plate-Mounted-Clamp-Mounted-or-Panel-Mounted-120-Vac-Transformer-40VA
This is so you don't overload the ARGO control transformer and the existing (or proposed) Taco Zone valves draw almost one full amp of current each. (the most of any other zone valve commonly in use) . Since you are using only 2 valves, the wiring is cut and dry and easy to follow.

When you start to have more than 2 zone valves, then I would recommend a zone valve control relay since there is a greater chance of error on multiple valve installations. But in this case, just 2 valves, keep it simple. follow the zone valve instructions and use the end switch (terminal 2 and 3) to power the ARGO zone 2 circulator. Always follow the same wiring procedure on all valves. Wire Terminal R on the thermostat to R from the transformer . Wire terminal W from the thermostat to #1 on the zone valve. Always wire #2 from the thermostat back to C on the transformer. If you follow this rule of wiring for a taco 571 zone valve, you will never have a problem in the future (like, if you need to add a smart thermostat). You can make it work with other wiring configurations but I find that other wiring configurations can cause problems down the road.

Mr.Ed

EdTheHeaterMan

That transformer can be mounted in a knock out on the ARGO control

DonB5

Wow! First, I'm sorry for the slow response; was away from computer last 2 days.

Second, thank you for this great information. Ed, I really appreciate the detailed instructions. I'm going to give it a go. And Steve and Ironman, thank you, too, for your helpful responses.

Don

DonB5

Ed, yes, you are correct, either thermostat would operate the #2 pump. Don