acproblem

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

paul52446m

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

acproblem

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

acproblem

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

paul52446m

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

acproblem

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 ?

paul52446m

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.

acproblem

thanks. so I shall connect the following way ?

JoeD

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

These are transistors, at least the bottom row is.

JoeD

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.