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Connecting a C-Wire, Need advise

Heating_Noob
Heating_Noob Member Posts: 2
edited November 2020 in Thermostats and Controls
I have heat only 2 zone force hot water system. L8148E Aqua stat controller. 40 VA external transformer. On the bottom of transformer, it has letters R (Load), and C. Does the C mean common??

The following is the wiring diagram but I'll try my best to describe it as well.

Stat-A "Rh" --> Trans "R"
Stat-B "Rh" --> Trans "R"
Stat-A "W1" --> TacoA "#1"
Stat-B "W1" --> TacoB "#1"
Stat-A "C" --> not connected
Stat-B "C" --> not connected

L8148E "T" --> TacoA "#2" --> TacoB "#2" --> Trans "C"
L8148E "Tv" --> TacoA "#3" --> TacoB "#3"
L8148E "w" and "z" are connected from factory with jumper

Should I connect Stat-A "C" & Stat-B "C" to Trans "C" or L8148E "z"

I used "A" for zone1 and "B" for zone2 in description.

Comments

  • Zman
    Zman Member Posts: 7,118
    You are going to want to connect to the C on the transformer not the aquastat.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Heating_Noob
    Heating_Noob Member Posts: 2
    Thank you very much. I connected to Trans "C" and it works great. The Voltage is pretty constant right now. I had 2 Nest both installed at same time and less than 1 year old. 1 die and 2nd dropping WiFi a lot. Hope this will fix the problem.
  • I'm impressed! That question-answer-realization process usually takes much longer.
    Often wrong, never in doubt.
    Zman
  • Zman
    Zman Member Posts: 7,118

    I'm impressed! That question-answer-realization process usually takes much longer.

    I am surprised as well, especially with a taco 3 wire valve in the mix. The OP posted a great diagram. That sure makes it easy.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein