Homeowner asked me to install the nest for them while I was here. Figure no problem but it's telling me it needs a common wire otherwise their boiler goes haywire.
I ran a new 5 wire to the HVAC but need to add the common wire that wasn't there before.
Which line has 24/7 power that I can branch that off of?
Homeowner tried to hook up herself, called nest they told her she needs a common wire because it's trying to draw power from the furnace to charge itself which is making the furnace go nuts.
Single zone system, works fine, red yellow green are all hooked up and system works fine on battery power thermostat. Nest needs common wire for recharging. Have blue wire and white spare wire left, I wrapped the white out of the way. Not sure where to jump the blue wire off of.
The way you are describing this, it sounds like she has a split system....Furnace in the basement, A/C air handler in the attic, is that what you are dealing with?
I don't know anything about the nest, but my fancy programmable Honeywell specifically wanted the power to come from the A/C air handler transformer and not the boilers transformer.
And like you, the boiler was easier to get to, but you do what you gotta do.
So you have a red wire from the air handler connected to RC, right. Then connect the common from the air handler. The boiler won't have a common like you are looking for. It has one, just some are harder to locate and use then others.
Why are you messing with the wiring on her system? You're obviously not licensed or insured to do so. One little problem and you can kiss that nice firefighting pension goodbye.
He's not preforming open heart surgery here he just has to jam a weenie wire under a screw with a big fvcking C below it...its pretty hard to monkey it up.
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