During recent renovations, we had to move our existing thermostat. Instead of replacing it with the same dumb 2-wire knob (white/red), I'd like to get a smart thermostat like the ecobee3. All of these new thermostats require a C-line, yet my heater does not have one currently. Can I add one to it?


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Lastly, if it is possible to add a C-wire to this board, is it something a licensed electrician would need to do, or is it safe for a tinkerer like myself to do?


Sure. I've highlighted the C wire in the wiring diagram.

DNV40NB Wiring Diagram

You'll have to bring a wire from the transformer in the heater, up to the thermostat location. This may require pulling a whole new 3 wire cable.

If there's an open terminal where the brown wire attaches to the transformer, you can connect the new C wire for the thermostat there. Otherwise, you'll have to tap in somewhere else.

This image shows how the new thermostat should be connected to the system.

How to wire new thermostat

WARNING: If you don't feel comfortable poking around yourself, don't hesitate to contact a local HVAC tech (or Electrician).

  • Thanks! I'll follow up if I decide to do it myself – coneybeare Jan 5 '18 at 19:23

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