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-   -   Is my furnace-thermostat wiring okay? (http://www.diychatroom.com/f17/my-furnace-thermostat-wiring-okay-55540/)

Brandon19 10-19-2009 07:26 PM

Is my furnace-thermostat wiring okay?
 
Hi, I bought a house and the installed thermostat was ugly, partly painted, and I couldn't figure out how to work it. I have installed a thermostat I had previously used in an apartment.

When I looked at how the old one was wired it was not what I expected. The colours of the wires did not match the labels. The furnace and fan still worked, but I still wanted to replace it.

This is what it looked like: (the blue text is the old owner's hand writing. the black test is what is actually on the stat. i just made it more visible in the pic)
http://img269.imageshack.us/img269/9994/img3359h.jpg

Since it worked, I figured I would install my new one the same as this one.

Here is a pic of the new one:
http://img4.imageshack.us/img4/333/img3365i.jpg

When using this new one, the furnace works, but it seems to turn on and off too much. One change I did notice is that when the system turns on, the fan starts blowing first, which is normal. But then it turns off, and ten seconds later the furnace and fan turn on. It's always 10 seconds.

Is my setup okay? I'm not sure why the wires would be different...

Here is a pic of my furnace, I'm not really sure where the wires from the stat go to be honest.

http://img43.imageshack.us/img43/891/img3363k.jpg

Am I okay?

Thanks!

Plumber101 10-19-2009 08:00 PM

First in the second pic of the stat there is a black jumper and there are markings HE and HG it needs to be on the HG not the HE

HE = Heating electric
HG = Heating gas

Also did you set the stat temperature differental to 2 deg?

Brandon19 10-19-2009 08:21 PM

Oh, thanks for noticing that. I'll put it on HG right away.

I didn't set any differential. I didn't know I could on this stat. Know how I would do it on this? And is that 2 degrees C or F?

Thanks a lot

Plumber101 10-19-2009 08:25 PM

Need more info..what is the brand and model of the new stat?

Brandon19 10-19-2009 08:34 PM

Brand and model are in the link in above post and below.

http://rona.ca/shop/~thermostat-prog...hermostat_shop

Not much detail on the page, but I did just find the instruction manual from it. Anything I should be looking for? I did not see any differential info.

In the instructions, beside the HG/HE jumper info, it says that HG allows the heating system to control the fan, not the thermostat. I wonder if that solved my 10 second delay problem already?

sktn77a 10-20-2009 03:15 PM

The wires going to the furnace don't look like they are the correct colors. If they didn't obey the standard thermostat wiring conventions, the last homeowner may have traced them and added the blue lables. But it sounds like its not working properly, anyway. I'd first try putting the old thermostat back in and seeing if this works properly. If it does, then trace the wires from the furnace back to the thermostat . If they are original (ie R=+24v, G=fan, W=heat, Y=cool and B=common) then it looks like the original thermostat was wired incorrectly - why it worked is anbody's guess.

SULTINI 10-20-2009 06:46 PM

Quote:

Originally Posted by Plumber101 (Post 342979)
First in the second pic of the stat there is a black jumper and there are markings HE and HG it needs to be on the HG not the HE

HE = Heating electric
HG = Heating gas

Also did you set the stat temperature differental to 2 deg?

101
Good Job, very observant


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