Hot water heating system zone valve installation wiring questions & answers:

Frequently-asked questions (and answers) about wiring heating zone control valves and zone controllers from all manufacturers.

This article series describes how to wire up heating zone valves. 

We include wiring diagrams and installation instructions for most zone valve model and multi-zone controllers, and we describe special wiring problems that can occur if you mix different types, brands, or models of heating zone valves on the same hydronic heating (hot water heating) system.

Page top photo: Honeywell V8043 Zone Valve showing a wiring connection terminal block.

Zone Valve Wiring Hookups for Hydronic (Hot Water) Heating Systems

These Questions & answers about wiring up heating zone valves & zone controllers, were posted originally

at ZONE VALVE MANUALS & WIRING INDEX

Annotated photo: Honeywell V8043-1000 series zone valve showing basic information about the red & yellow wire connections discussed on this page.

[Click to enlarge any image]

On 2018-02-22 by (mod) - what are the wire color codes on a White Rogers 11d05

Oui Jean

R = Rouge (red)

W = Blanc (white)

B = Noir (black)

On 2018-02-22 by jean blanchette

pour être certain,l'aquastat pour bouilloire white rogers 11d05-1 les connections d'arrivée du courant sont bien

dehaut en bas R pour rouge ,

B pour noir et

W pour blanc,MERCI, j.blanchette@hotmail.fr

On 2018-02-03 by (mod) - Taco SR 502 Zone Switching Relay Wiring Chart

The Taco SR503 zone relay is a bit different as we illustrate below.

Both installation instructions can be found by links in the article ZONE VALVE MANUALS & WIRING INDEX

On 2018-02-03 by (mod) -

Juan C.

I don't blame you for saying "if I understand you correctly" since when I posted this effort at a reply I was a bit uncertain about just what equipment you have installed - and found myself doing some arm-waving that led to a rather general answer.

Often with one circulator and two zone valves, you are using a zone relay like the Taco example I have - the SR502 illustration I'll include here - you'll see that the zones are wired into the relay and the relay in turn turns the one circulator on and off as needed. You will not need a second circulator.

On 2018-02-03 by Juan Carlos

First of all, thank you!

If I understand you correctly, if I get a two zone relay (ie Taco SR502-4 Switching Relay) and two zone valves, if I wire the one circulator and the valves to the relay there would be no need for the additional circulator? Would I follow the wiring diagram that you have posted for the Taco relay?

On 2018-02-02 by (mod) - Two zone valves and zones can be served by one circulator pump.

Juan

Two zone valves and zones can be served by one circulator pump.
In the wiring setup,

Each individual thermostat is wired to an individual zone valve.

On a call for heat the thermostat acts like a "switch" to cause the zone valve to open (to permit hot water to flow through the zone).
When the zone valve is fully open, and end-switch in the valve in turn switches on the circulator pump, or where there are multiple zones it will be wired to a circulator relay controller that in turn operates the actual circulator.

That arrangement allows either or both zone valves (and thermostats) to call for heat at any time.

On 2018-02-02 by Juan Carlos

With a zone relay and zone valves, do I need more than one circulator? Or would the relay & valve turn that one circulator on? I have two zones.
Thank you

On 2018-01-24 by (mod) - some of our rooms are too hot

Bill

Have you first-tried cutting the heat output from the baseboards in the room you want to be cooler:

1. close the vane at the top of the baseboard heat outlet

2. if further heat cut is needed, you can try blocking the air inflow at the baseboard bottom underside, temporarily just using a few rolled towels.

Cutting the air flow across the baseboard won't stop it from getting hot but you'll significantly cut the heat transfer into room air.

Yes an alternative, which depending on heating zone piping layout can be a bit of trouble, is to pipe the to-be-cooler room as a separate loop or zone or even a sub-zone.

Any conventional 24VAC wall thermostat can control the new zone valve.

On 2018-01-23 by Bill Ragland

Older daughter lives with me. She has hormonal problems and choose to be in very cold rooms.

The 2 baseboard heater thermostats in these rooms. Th rest of our rooms stifling.

I plan to run the 4 wire brown thermostat wire from my bedroom with normal temperature needs to the two valve boxes, switch out the current thermostat wires with the new ones and hook the other ends to a new dual zone thermostat in my room. I need recommendations for the new thermostat. Thanks

On 2017-12-11 by Gene 12/9/17

I have Honeywell V8043F zone valves I have them wired as they are supposed to be but the end zone wires where do they go ? And the thermostat wires to the 24 volt relay to the pumps . Can you show diagram as to how these connect ? The relays are Oron G 2R-2S .I have had these together last winter but I don't remember how they were .Thanks

On 2017-12-10 by JJ

Hi, Should a circulator pump run on a cold boiler or should it wait to call for heat after the boiler makes temp(180)? My taco come on when you turn the boiler on and the room temp is lower than the thermostat min. setting ( 52).

Takes 25 mins to come to temp instead of 10. I have 3 zones 3 pumps no zone valves. Older Honeywell relays/controllers, older taco circulator.

On 2017-12-09 by (mod) - when two of your zone valves are wired normally closed and two are wired normally open

Revised from prior comment

Gene,

I'm pretty sure that when two of your zone valves are wired normally closed and two are wired normally open you need to take care not to run into both wiring incompatabilites and also low voltage transformer overloads and burnout. But we can confirm that your zone controls are wired properly by finding the installation wiring guide for your particular Taco zone valve model.

We give Taco zone valve wiring instructions and links to PDF copies of installation guides at ZONE VALVE WIRING and also at .

The thermostat is wired to the zone valve and on a call for heat opens the valve (in a normally-closed zone valve design). Once a zone valve is open it makes an end switch witch turns on your circulator relay.

On a normally-open zone valve the thermostat closes the valve and turns off the circulator.

We describe that wiring in the ZONE VALVE WIRING article.

If you previously had all these working and you haven't change the wires I would start by asking if it's possible that the low voltage Transformer has failed from being asked to run too many zone valves. An overloaded Transformer and work for years until a coincidence all of the Zone Motors are asked to run at the same time.

Also I'm interested in obtaining a Mercury bulb type thermostat for research purposes. If you're willing to exchange I'll be glad to mail you a newer non Mercury thermostat by Honeywell. Use a page bottom contact link and I can give you the details.

On 2017-12-09 by Dec. 8 2017 Gene

I forgot to add my name to the to the problem below.

I have 3 small pumps and and 6 zone valves which as near as I can tell they are V8043F by Honeywell ad 6 thermostats can you tell me how to get these to all connect and work properly .

The 4 thermostats are Honeywell round with mercury for connection and 2 Honeywell digital cheap programable type. and I am using 6 Omron G2R-2-S 24 volt VAC relays for 110 or 220 volt .they have 2 normally open and 2 normally closed

I have had 4 zone valves working great for 2 or 3 winters and I had 2 more zone valves to connect with wire they were already in the pipe system this is for under floor added heat. And if you can help me with I had also I had indicater light that would light up each time a relay connected .

I seamed to have lost how of this this was be for but it worked well last winter . Can you help me ?

On 2017-12-09 by (mod) - mercury bulb thermostats wanted for research - limited exchange offer

Email is at the page top or bottom CONTACT link

Here are DETAILED WIRING DIAGRAMS FOR HONEYWELL ZONE VALVES V8043E & T822 & T822

Also see HONEYWELL V8043 ZONE VALVE - [PDF] complete installation and wiring instructions.

Watch out: some multiple zone controllers permit assigning one of the zones as a "priority" zone - typically used to assure that an indirect fired water heater for domestic hot water supply will get priority over heating zones.

A typical design will permit the priority zone to run while shutting down the other zones for an hour, the controller figures if you're still in the shower you ought to get out - so it turns the other zones back on.

On 2017-12-09 by Gene 12/8/17

@Dec. 8 2017 Gene, Yes I will exchange one with you. what is your email

On 2017-12-09 by (mod) - trouble hooking up wiring for Taco zone valves and controller

Gene,

I'm pretty sure that when two of your zone valves are wired normally closed and two are wired normally open you need to take care not to run into both wiring incompatabilites and also low voltage transformer overloads and burnout.

But we can confirm that your zone controls are wired properly by finding the installation wiring guide for your particular Taco zone valve model.

We give Taco zone valve wiring instructions and links to PDF copies of installation guides at ZONE VALVE MANUALS & WIRING INDEX and also at .

The thermostat is wired to the zone valve and on a call for heat opens the valve (in a normally-closed zone valve design). Once a zone valve is open it makes an end switch witch turns on your circulator relay.

On a normally-open zone valve the thermostat closes the valve and turns off the circulator.

We describe that wiring in the ZONE VALVE MANUALS & WIRING INDEX article.

If you previously had all these working and you haven't change the wires I would start by asking if it's possible that the low voltage Transformer has failed from being asked to run too many zone valves.

An overloaded Transformer can work for years until by coincidence all of the Zone Motors are asked to run at exactly the same time.

Also I'm interested in obtaining a Mercury bulb type thermostat for research purposes. If you're willing to exchange I'll be glad to mail you a newer non Mercury thermostat by Honeywell. Use a page bottom contact link and I can give you the details.

Shown below: the Omron G2R 24VAC - 120/240V switching relay discussed by the reader Gene.

On 2017-12-09 by Dec. 8 2017 Gene

I forgot to add my name to the to the problem below.

I have 3 small pumps and and 6 zone valves which as near as I can tell they are V8043F by Honeywell and 6 thermostats - can you tell me how to get these to all connect and work properly .

The 4 thermostats are Honeywell round with mercury for connection and 2 Honeywell digital cheap programable type.

and I am using 6 Omron G2R-2-S 24 volt VAC relays for 110 or 220 volt .they have 2 normally open and 2 normally closed .

I have had 4 zone valves working great for 2 or 3 winters and I had 2 more zone valves to connect with wire they were already in the pipe system this is for under floor added heat.

And if you can help me with I had also I had indicater light that would light up each time a relay connected . I seamed to have lost how of this this was be for but it worked well last winter . Can you help me ?

On 2017-10-16 by Barry

Is it possible to control 1 Honeywell V4043 valve from 2 seperate thermostats (one wired with its own clock and one from a programmable clock and thermostat) so that whichever stat is asking for heat (even both) then the valve will be opened.

The valve will only close when neither stat is demanding heat?

On 2017-10-11 by Mike

Im replacing a zone valve in a 2 zone system. Old zone valve has 5 wires but new zone valve has 4

I followed all wires took apart 1 for 1 and matched them up.

2 wires to zone motor and

two wires to end switch i believe.

I dont know what to do with the fifth wire

On 2017-03-26 by (mod) - two zone hot water system that was wired wrong

I'm not sure what the other wires and devices are in your description so I'm chicken to give too specific advice but I'll include some general advice here and also refer you to our ZONE VALVE MANUALS & WIRING INDEX article.

I would follow the thermostat wires to see where each thermostat is connected.

I'd expect to find each thermostat going to one circulator control relay, or on some systems, one circulator relay is in the main boiler aquastat and the second relay is a separate wall-mounted device.

At HONEYWELL ZONE VALVE INSTRUCTIONS we describe how the red and yellow wires for a zone valve are usually connected:

One yellow wire connects to the C terminal on the low voltage transformer.

The second yellow wire connects to a "heat on" wire from the room thermostat.

One red wire connects to the R-side of the transformer (Think "R" = "Red")

The other red wire conects to one side of the external DPDT relay that operates the circulator pump. (DPDT = "double pole, double throw" switch)

On 2017-03-26 by joe - my two zone hot water system is wired wrong

hi my name is joe,

i have a two zone hot water system that was wired wrong ,

when the first floor call for heat both of the zones turns on and when it goes off turns both them off .looks like that the wire from the therm and the tranf and the motor are connected right ,

but there are 2 red wire that coming from the a device on the chimny that are also connected by the valves and motor i m assuming that is a cut off safety ,

i have been looking on the web and i haven't find one boiler wired up that way . can anybody tell me how to wire up the right way .thank in advance

On 2017-01-29 by Ron Walker

I put a new thermostat onto a 4 zone system. as soon as I did now I have no power to any of my thermostats.

...

Continue reading at ZONE VALVE WIRING - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Zone Valve Articles

• CIRCULATOR PUMPS & RELAYS
• ZONE VALVES, HEATING - home
  • DISSOLVED OXYGEN DAMAGE CONTROL
  • ZONE CONTROLLER TACO ZVC403
  • ZONE VALVE BANGING or BACKWARDS
  • ZONE VALVE MANUALS & WIRING INDEX
  • ZONE VALVE SIZE vs GPM

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ZONE VALVE WIRING FAQs-2 at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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INDEX to RELATED ARTICLES: ARTICLE INDEX to HEATING BOILERS

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