# how to connect zone valve to thermostat and transistor ?



## acproblem (Jan 4, 2012)

I have a problem to connect the thermostat/transistor wires to upper part of the zone valve (the picture with a red circle). I needed to replace the valve as it was leaking water. Now the new valve is on and the new cap is on ..however the wires are still dangling there ;-))
There is one wire coming from transistor - red wire
There are 3 wires coming from termostat (red, black and white). My termostat is heat only (I am heating running hot water in baseboards) so I am not sure the black wire is to be used. Can somebody pls let me know which screw of the valve cap I shall connect the wires to?. Maintenance guy told me if I do it wrong .. I might fry some part in new valve cap or termostat. Thanks a lot for your help


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## paul52446m (Jan 4, 2012)

acproblem said:


> I have a problem to connect the thermostat/transistor wires to upper part of the zone valve (the picture with a red circle). I needed to replace the valve as it was leaking water. Now the new valve is on and the new cap is on ..however the wires are still dangling there ;-))
> There is one wire coming from transistor - red wire
> There are 3 wires coming from termostat (red, black and white). My termostat is heat only (I am heating running hot water in baseboards) so I am not sure the black wire is to be used. Can somebody pls let me know which screw of the valve cap I shall connect the wires to?. Maintenance guy told me if I do it wrong .. I might fry some part in new valve cap or termostat. Thanks a lot for your help


You only need the one from the transformer and two from the stat, as long as that zone valve is spring loaded return. I can't see the letters on the valve, can you tell me what they are?   Paul


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## acproblem (Jan 4, 2012)

paul52446m said:


> You only need the one from the transformer and two from the stat, as long as that zone valve is spring loaded return. I can't see the letters on the valve, can you tell me what they are?   Paul



it is a Taco 571-2 
<--    (one way)


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## acproblem (Jan 4, 2012)

acproblem said:


> it is a Taco 571-2
> <--    (one way)



I am adding the wiring instructions...there are 2 t-formers though ...2 zones ?


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## paul52446m (Jan 4, 2012)

acproblem said:


> I am adding the wiring instructions...there are 2 t-formers though ...2 zones ?



Did they use all the wires before?  Look at you stat and which wires are tied in there?   Paul


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## acproblem (Jan 4, 2012)

paul52446m said:


> Did they use all the wires before?  Look at you stat and which wires are tied in there?   Paul



I do not think so the black was used at all - it is heat only thermostat. I have put new thermostat. I also think 1 wire from transistor is missing...normally tranasistor should have 2 wires correct ?


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## paul52446m (Jan 4, 2012)

acproblem said:


> I do not think so the black was used at all - it is heat only thermostat. I have put new thermostat. I also think 1 wire from transistor is missing...normally tranasistor should have 2 wires correct ?



If it is red and white going to stat, put red from transformer to post 2 on the zone head, put red from stat to the other post of the transformer, put white from stat on post one of the zone head.


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## acproblem (Jan 4, 2012)

paul52446m said:


> If it is red and white going to stat, put red from transformer to post 2 on the zone head, put red from stat to the other post of the transformer, put white from stat on post one of the zone head.



thanks. so I shall connect the following way ?


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## JoeD (Jan 4, 2012)

It's not a transistor. Stop calling it that. It is a transformer.

These are transistors, at least the bottom row is.


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## JoeD (Jan 4, 2012)

That diagram would certainly turn on the valve. But what turns on the heat? There is more to the system than just the valve and thermostat.


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## paul52446m (Jan 5, 2012)

acproblem said:


> thanks. so I shall connect the following way ?



That't the way to do it.  paul


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## paul52446m (Jan 5, 2012)

JoeD said:


> That diagram would certainly turn on the valve. But what turns on the heat? There is more to the system than just the valve and thermostat.



Hi JoeD Paul here. In his first post a few days ago , he said he was on the 5th
 floor of a large apartment building so i am assuming since there is not enough wires there to have a cable running to the boiler, that the boiler system has a main that runs hot all the time. It would be controlled by a indoor, outdoor stat, which would control the water temp. This way each apartment can have heat when ever they want it. I have put in system like this and worked on many of them. It would be a bank of boilers.  Paul


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## acproblem (Jan 5, 2012)

JoeD said:


> That diagram would certainly turn on the valve. But what turns on the heat? There is more to the system than just the valve and thermostat.



this is a 50 unit condo. the hot water is provided in the pipe. Problem is I have received another diagram from an electriciain ..he wants to :

Red wire from Transformer to Red from Thermostat.
The white wire from transformer to screw marked "2" on the valve.
The other thermostat wire (I don't know the color) to screw marked "1" on
the valve.
That should do the trick.


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## paul52446m (Jan 5, 2012)

acproblem said:


> this is a 50 unit condo. the hot water is provided in the pipe. Problem is I have received another diagram from an electriciain ..he wants to :
> 
> Red wire from Transformer to Red from Thermostat.
> The white wire from transformer to screw marked "2" on the valve.
> ...



he is telling you what normal color code would be . both ways will work. paul


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## acproblem (Jan 5, 2012)

paul52446m said:


> he is telling you what normal color code would be . both ways will work. paul



he is telling me to connect reds together from thermostat and transformer and run abother cable from the other screw on the transformer to screw #2 on the valve (he calls it white)

you are telling me to connect red from thermostat to the screw on transformer and run the other red from transformer to screw #2 on the valve

so the common denominator so far is :
white wire from the thermostat runs to screw #1 onthe valve 

so ..both ways will work ? really dont want to damage $100 part of transformer...


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## paul52446m (Jan 5, 2012)

acproblem said:


> he is telling me to connect reds together from thermostat and transformer and run abother cable from the other screw on the transformer to screw #2 on the valve (he calls it white)
> 
> you are telling me to connect red from thermostat to the screw on transformer and run the other red from transformer to screw #2 on the valve
> 
> ...



Just use his diagram and it will work fine.   Paul


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## JoeD (Jan 5, 2012)

His diagram is the same as yours. He is just using different colours. 

The basic principle is that one of the wires between the transformer and the valve has to go through the thermostat and get switched.


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## acproblem (Jan 5, 2012)

JoeD said:


> His diagram is the same as yours. He is just using different colours.
> 
> The basic principle is that one of the wires between the transformer and the valve has to go through the thermostat and get switched.



does the transformer has 2 different poles ? like + or - ? 
does it matter to what screw I connect the wire coming from the thermostat and then from transformer to the valve ? if it does not then yes ..either diagram is ok. if it does then I need to know which wire goes where ....


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## paul52446m (Jan 5, 2012)

acproblem said:


> does the transformer has 2 different poles ? like + or - ?
> does it matter to what screw I connect the wire coming from the thermostat and then from transformer to the valve ? if it does not then yes ..either diagram is ok. if it does then I need to know which wire goes where ....



It does not make any difference. Take one wire from the transformer ether post and put it on post 2 of zone valve. Take the other transformer post and run that
 to stat ether wire as long as you use one of the wires tied to the stat. the other wire coming back from the stat goes to the post 1 of the zone valve
 Transformers do have a common and a hot post but in your case it does not matter. If you was using a heat antisapator than it would make a difference. You would run the hot post from the transformer to the stat. paul


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## acproblem (Jan 5, 2012)

paul52446m said:


> It does not make any difference. Take one wire from the transformer ether post and put it on post 2 of zone valve. Take the other transformer post and run that
> to stat ether wire as long as you use one of the wires tied to the stat. the other wire coming back from the stat goes to the post 1 of the zone valve
> Transformers do have a common and a hot post but in your case it does not matter. If you was using a heat antisapator than it would make a difference. You would run the hot post from the transformer to the stat. paul



this assumes my thermostat does not have a heat anticipator ...what if it does ? I should be able to open it up and see inside if there is some thing to adjust ...that would be the heat anticipator, correct ?


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## paul52446m (Jan 5, 2012)

acproblem said:


> this assumes my thermostat does not have a heat anticipator ...what if it does ? I should be able to open it up and see inside if there is some thing to adjust ...that would be the heat anticipator, correct ?



I do not use a heat anticipator on hot water heat, so if you have one run it up to hi setting like 1.2 amp. If you do want to use it then you would have to take a amp check at the stat and set it to that reading, but like i said you do not need it so set it hi so you don't short cycle.  Paul


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## acproblem (Jan 6, 2012)

paul52446m said:


> I do not use a heat anticipator on hot water heat, so if you have one run it up to hi setting like 1.2 amp. If you do want to use it then you would have to take a amp check at the stat and set it to that reading, but like i said you do not need it so set it hi so you don't short cycle.  Paul



I do not think so I have one (heat anticipator) in the thermostat. pictures attached...thanks for all your help !!


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## paul52446m (Jan 6, 2012)

acproblem said:


> I do not think so I have one (heat anticipator) in the thermostat. pictures attached...thanks for all your help !!



Just hook it up it should work ok.    Paul


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