Nest power adapter and Taco zone valves


  #1  
Old 05-24-22, 08:10 PM
J
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Nest power adapter and Taco zone valves

Hi, I am planning to install the Nest Power Adapter to solve my low power problem on one of my Nest 3rd gen tstat. My hvac system has a total of 4 zones. 2 zones are Heat only, the other 2 zones are Heat & ac. I have 4 of the Nest tstats, but only one is having the low power problem, currently.

I do not see instructions for wiring the device into the Taco valve. I will try to attach a picture of the valve wiring and appreciate if anyone can assist.

The Nest tstat that has the low power problem is the Dining Room. Iím trying to wire the Nest Power Adapter for this zone.
 
  #2  
Old 05-25-22, 09:58 AM
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The dining room valve is driven by a green wire that comes from a cable with red and white. This means that there is a splice upstream that you need to find and would likely be where the Nest Power Adapter needs installed. Find that and provide pics.
 
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Old 05-25-22, 10:45 AM
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It looks like the dining room thermostat comes in on green and white. Red is cut off.

If that is correct.................
Disconnect the white wire from R connection and green from ZV terminal 1.
Connect these two wires to the dark gray nest adapters wires. No polarity here.

Connect light gray adapter wire R to R splice.
Connect light gray adapter wire W to terminal 1 on ZV.
Connect light gray adapter wire C to terminal 2 on ZV.
 
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Old 05-30-22, 07:03 AM
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Thank you PJmax. After confirming the tstat white and green wires, I wired in the power connector as you suggested. However Iím seeing only 3.6V (which I think is too low) but it is 40mA (which I believe is good). The tstat is offline, saying low power.

I measured the green and white (heat wired) at the tstat with a multimeter, and it is 24V. This dining room tstat controls both Heat and ac. I also measured the ac wires and it is 26V




Thanks
 
  #5  
Old 05-30-22, 02:55 PM
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You didn't mention anything about A/C
When both are connected the thermostat power needs to come from the A/C.
 
 

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