So Im installing a new thermostat that requires c power from wire.Unfortunately, I can't determine myself if the particular control box at the furnace contain the transformer point for a c connection junction point.My furnace is a oil burner with hot water heat.Current wire in the walls half 3 conductor.Thoughts on how to wire this? Do I need new controller box? Thanks for in advancve - apreciate youre help!
water furnace thermostat
Dec 28, 2020
Last reply: 5 years ago
4 Replies
Not sure exactly what your problem is but there are devices that will "add" one conductor between the furnace and the thermmostat.
How many wires does the thermostat require? What make and model is your thermostat?
What make and model furnace to you have? Do you have AC also. Why do posters provide so little background information?
Please post a picture of the wiring. Thanks!
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Two obvious choices.
1 - Get someone that understands the basics to look at what's at the furnace, eg where does the thermostat cable originate from, where is the transformer, is there an extra wire in the cable that is connected or can be connected. I'd bet that the common is accessible, bigger question if you have an extra wire for it.2 - Get a thermostat that doesn't need a common wire. Usually the main purposes for that are to light it up and so that a battery isn't needed. I have a Honeywell VisionPro that I highly recommend. It has a backlit display and will work with either a common or without. With a common it's backlit all the time on low, if you touch it then it goes to full brightness. Without a common, using the battery, it's dark unless you touch it, then it goes to full brightness for a couple minutes.
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