Adding C wire to zone valves on TT

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Old 02-18-20, 07:05 PM
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Adding C wire to zone valves on TT

Hello all
im trying to upgrade thermostats to wifi, like everybody else i have only two wires at thermostat.
so i have 3 zones and 3 thermostats, so far i ran new wires to 2 thermostats (its proly gonna take a long time till i get to third floor or i wont at all) so now i need to make C connection at furnace and i need advise where to connect it,
only first thermostat has jumper from R to Rc, others just R and W
here are some pictures how is made right now.
thanks for help
 
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  #2  
Old 02-18-20, 08:36 PM
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Welcome to the forums.

One question...... is your wiring diagram correct..... right down to the wire colors ?
 
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Old 02-18-20, 09:04 PM
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With only two wires from the stat to the zone valve..... polarity doesn't matter. Now with three wires..... polarity is very important. Technically your system is wired exactly backwards. R stands for 24v which is common power to all stats and W is heat which goes to each valve. It doesn't matter what you do..... reverse the wires at the stat or change the connections.... the hookup must look like these diagrams.

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There is no marking on the transformer.
One terminal is used as the 24v supply and one is used as the common.
 
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Old 02-19-20, 05:00 PM
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i checked two times and yes that how is everything connected, except i made mistake at TT, that red wire on left and white wire on right. does it matter?
so i redraw diagram does it change anything from what you draw ?
does it change anything if i have indirect hot water heater, but seems that it has his own control board
im dummy on heating systems, so im sorry for stupid questions
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and this is indirect hot water Name:  IMG_3387.jpg
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Old 02-19-20, 05:46 PM
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The wiring to the thermostats all connects at the zone valves. When a zone valve opens it commands the boiler/circulator to run. So we're not connecting anything additional to the aquastat.

You're not following my diagrams. Look at the top one again.

You have an R terminal on the thermostat. That terminal must be fed 24vAC.
You have a W terminal on the thermostat. That terminal must go to terminal 1 on the zone valve.
Common to the thermostat is the same as terminal 2 on the zone valve.
 
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Old 02-25-20, 07:50 PM
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Finally I had time to do it.
i changed connections at valves and it works
thank you PJmax
 
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Old 02-25-20, 09:10 PM
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You're welcome. Thanks for letting us know how you made out.
 
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Old 12-08-20, 11:47 AM
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Can I make the Green wire a common wire?

I have 3 Nest WiFi thermostats. Can I use the Green wire as a common wire? I tried and kept getting low battery error. The wire is actually Green all the way to the control board and then switches to Red.
 

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Old 12-08-20, 12:21 PM
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First that drawing has the R and W reversed at the Nest. Then C (green wire) would go to the center terminal of the zone valves.

Basically the thermostat's R and C need to connect back to the 24vac transformer. Then W goes to the valve to activate it.
 
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Old 12-17-20, 10:43 AM
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On your Zone valves, lets label the terminals 1, 2, and 3. With "1" being the thermostat side. Lets ignore wire colors for right now. The hot terminal on your transformer goes to "R" on your nest. "W" on your Nest goes to terminal 1 on your zone valve. The other terminal on your transformer, this is the common terminal, goes to "2" on your zone valve and goes to "C" on your Nest. Your nest is not fully powered and can actuate the zone valve.

Now, for the zone valves to signal the boiler there is a call for heat, you need to wire in terminals 2 and 3 on the valve. Your boiler has "TT" terminals. One "T" is 24VAC and the other is common. Once you know which one is 24VAC (check with a voltmeter), that T attaches to Terminal 3. DO NOT ATTACH 24VAC TO TERMINAL 2. Your other T connects to terminal 2 on your zone valves.

Wire colors are meaningless, however, typically red caries 24VAC and white is a signaling wire.

ONE IMPORTANT THING TO NOTE. Three zone valves and three nests are a lot for one transformer. What is your transformers VA? You may overload it and kill it. Easy fix; buy a bigger rated transformer.

Now to actually answer your question, the green wire on valve one makes no sense. It isnt doing anything. If you move it to terminal 2, as mentioned above, that will connect it with the common terminal on the transformer and now provide it constant power.

 
 

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