Deep Dive Switching Relays and Zone Valve Controllers

Presented by John Barba, Dave Holdorf and Rick Mayo
From the simple to the sublime with hydronic zone controls. You’ve designed a system either with Zone Circulators, Zone Valves or both. Here we will review how to choose what you need and wire them up.

[@lprice5583]

Great content! I don't understand how this doesn't have a million views.

[@TacoHVACtv]

Thank you, Levi!

[@dave0028]

Great video. I will be installing a Buderus G215/6 boiler with a 220v burner. I have the primary pump on the boiler and a secondary pump that will go to my garage in floor heat. I need help with the wiring such as how to wire the Honeywell L7224 aquastat to the Taco SR503-EXP-4 controller etc.

[@TacoHVACtv]

Hi Dave, thanks for watching one of the Taco Tuesday webinars, we greatly appreciate it. Below is the link to our complete wiring guide, look for your application starting around page 83. www.tacocomfort.com/documents/FileLibrary/100-92.pdf

[@philipwischmeyer6301]

I am wiring ASCO red hat solenoid valves into aTACO 403. The soilenoid valves have 3 wires: 2 reds and 1 green with a yellow stripe. Will that green&yellow go on 1 or 2, with the reds on 3&4?

[@dlmob]

Awesome video. Does the SR506 exp have 2 dry contacts? That way I can have my ibc boiler smart board switch between zone heat and IDHWH. Currently with the sr506 I have, if the house is heating using 110 degree water based on the outdoor reset and the idhwh calls for a replenish at the programmed 160 degrees well that then pushes 160 degree water through my home heating at the same time because the circulator pumps don’t shut off because the thermostats are still calling for heat. I’m told the exp is the fix for this because of the two dry contacts.

[@TacoHVACtv]

That is correct, you would need the SR506-EXP, it has the two dry contacts you are looking for.

[@LiloUkulele]

I building a closed loop system using a brazed heat plate exchanger. Will have a pump on the tankless WH side and a pump on the hydronic side. What kind of switching relay and thermostat should I use?

[@TacoHVACtv]

If both circulators are designed to turn at the same time, then a SR501 can be used if you are using circs with a total load of under 6 amp power draw. For a thermostat, you can use whatever brand and features you want. It will depend upon the number of wires in the wall that are from the room you are heating and the mechanical room.

[@tedcolarusso4406]

In the 4 zvc examples, does dhw always need to be set as priority? How can 2 circulators (system + dhw) be wired without dhw priority, allowing heat to continue running with a dhw call?

[@TacoHVACtv]

Ted, DHW circulators do not need to be setup on the ZVC controllers. Most of the time it is based upon the boilers being used and recovery time of the the DHW tank. If you do not want to use the Priority feature of the controller, you don't have to do anything, the default setting of the ZVC is that that zone operates just like any other.

[@ttucci215]

I am attempting to install wifi thermostats on a older version of the taco board. Mine is a taco SR 503. My zones don't have the common wire on each zone. I do see a common and 24v section in the top left corner of the board. My questions are can I use that for my common wire? And if so can I run two thermostats from that one section? It says the transformer voltage is 120vac input. The maximum combined load is 15amps.

[@TacoHVACtv]

Hello Tony, The wifi style thermostats on a SR 503 panel can be challenging. The quick answer to your question is yes, you can use the top left terminals for 24v power. The second part of this answer there may not be enough power at those terminals to power the controller and those new thermostats. That terminal is designed for smaller power loads. Our suggestion is to use an external transformer to power the thermostats. If you are not sure how to connect or your instructions from the thermostat manufacturer are not sufficient, please contact your plumbing and heating professional and/or Technical Services here at Taco. Thank you

[@abacojack13]

Question. what controller would I use and how would it be wired if I had 4 zones (4 circulators) and on each zone manifold I wanted to use actuators to split the zone into separate sub-zones each with its own thermostat. can you do a video on that?

[@TacoHVACtv]

@abacojack13 Thanks for watching Taco Tuesday, greatly appreciated. There are several ways this wiring can be completed. The first is if the manifolds are remotely located. I would install a zone valve controller (ZVC) at each manifold location, thermostats and actuators wired at that location. Then take the end switch wire from each ZVC and bring it to the mechanical room where the circulators are. At that point, you would need a switching relay (SR) to handle the 4 circs. That end switch wire will then go to the TT terminal for the corresponding circ.

[@TacoHVACtv]

The second way is if the manifolds are near the circulators, then you would need a ZVC for each manifold and the corresponding circ would then be wired to the ZVC

[@theplumber585]

Hello, I am working on a system with 6 zone valves and a system pump. One of the zone valves is a low temperature in floor bathroom and the rest a copper fintube. The low temperature zone comes off a mixing valve and has never really worked. It should have been controlled by a circulator. I am going to remove the low temperature zone valve and replace it with a circulator. Is there a control that will allow me to wire all of this or will I need to use a ZVC6 or ZVC5 and a SR501 for the pump zone?

[@TacoHVACtv]

Hello The Plumber, When it comes to a multiple temperature system like this where you need a lower temperature for the radiant floor zone, then yes, you need an additional circulator after the mixing valve, that's why it hasn't worked well. However the Zone Valve Controller can only control one circulator and you already have it used with the 5 zones of copper fintube. So you will need an additional SR501. I hope this helps.

[@boundlessintrepiddiscovery7242]

is there a max distance that the controller can be from the valves? (//max wiring length?)

[@TacoHVACtv]

I wouldn't go more that 75' with 18/4 wire to the zone valves. However, the beauty of the ZCV-EXP models allow you to install the Zone Valve Controller remotely (close to the zone valves) and then using the Expansion terminals ABC, you can daisy-chain from one controller to the other.