Thermostat Wiring


  #1  
Old 11-08-02, 09:57 PM
tchase65
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Thermostat Wiring

Hello ! We recently moved into our home, and while stripping wallpaper removed what appeared to be an old manual dial thermostat; it turned out this was the thermostat for our gas fireplace (we didn't realize at the time, as it was not in the same room as the fireplace). Unfortunately, we just taped up the wires and have no idea how they were connected.

I have since purchase a new digital thermostat (LUX 100), but we are having problem determining the wiring. We have three wires, 2 yellow and one black - none seem to have power. The millivolt wiring diagram seems to indicate we only need two wires connected:

G - Fan Relay (None)
Y - Cooling Compressor (None)
W - Heating Control (Connected to 24 Vac & Gas Valve)
RH - Heating Transformer (Connected to 24 Vac)
RC - Cool Transformer (Connected to RH)

Which wire colour is which ? Should we be joining 2 wires together, and if so, which ones ?

If anyone can help, I would greatly appreciate it.

Thanks in advance,
Tina & Jamie
 
  #2  
Old 11-09-02, 01:13 PM
ahasbeen
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Gas fireplaces aren't my bag of tea so you should wait and see if someone else jumps in on this. That said, you removed an old manual dial stat with three low voltage wires- 2 yellow and a black, and taped them together. For a gas fireplace you only need two wires to operate the gas valve Three if you have a fan. You need to kill all power to the unit and find out where these wires go. One, probably the black, would go to the xformer. a yellow would probably go to the gas valve and the other yellow may go to a fan relay/control. You can also find out by manually touching the black to a yellow, then black to the other yellow. This will tell you which wire goes to the valve and the fan, if there is one. You want to make sure you're dealing with 24 low voltage volts before trying this. Better to be safe than sorry. At the stat, you're only concerned with RH, w and F. As I said, maybe some else more familar with this will jump in with somew advise.
 
  #3  
Old 11-09-02, 02:59 PM
fjrachel
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You mentioned 'millivolt wiring diagram' and 'old dial t'stat'. If your fireplace has a pilot generator, your new t'stat will not work. You'll need a millivolt t'stat. Millivolts are VDC and much lower than 24VAC.
 
  #4  
Old 11-10-02, 12:12 PM
tchase65
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Ty and fjrachel: Thank-you both for your replies.

It turns out some friends of ours have the exact same fireplace, so we were able to borrow their manual and get a little further. We have at least located the pilot controls and a switch. Unfortunately, this manual also indicates we should have white and black wires. I guess we're going to have to trace them back and see where they connect.

As for the old thermostat, I guess I should have stated the "prior" thermostat, as the fireplace was only installed about 4 years ago. The prior one got misplaced after we removed it, and I decided I'd prefer a digital one. The new thermostat I purchased is a millivolt one, and the millivolt wiring diagram I was referring to was the one supplied with the new thermostat. I hope this clears things up a bit.

Based on that, should there be a problem getting this to work ? The fireplace manual only shows hooking it up to a wall switch. Is it safe to assume the same wiring would apply to the thermostat ?

Thanks again,
Tina & Jamie
 
 

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