I am trying to run a new c-wire for my new ecobee thermostat. When I finished running the c-wire from the thermostat it did not turn on. I tested the voltage at the boiler and it is only reading 17ac on the multimeter. Is there a way to fix this so that it powers my thermostat?

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  • Which terminals on the boiler did you measure 17VAC between? May 13 at 1:49

Yes you have 24vac at your boiler. Assuming you have enough conductors in the wire to your thermostat, it can be powered.

How many wires come from your thermostat to the boiler? The old thermo in the wiring diagram looks to just be a switch on the hot leg of the 24vac, you'll need the neutral side ( c-wire ) run to the thermostat as well. Where did you pull your c-wire feed from ?

It looks like you've circled something that has a ground, an aquastat, and the outgoing hot leg and incoming hot leg of the 24v.

The wire nut you've circled - I am going to assuming is your new c-wire - has a blue wire and a black wire and I can't tell where either of them go.

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