new thermostat

Old 10-13-03, 09:28 AM
Visiting Guest
Posts: n/a
new thermostat

We have an oil furnace that works very well, but it has an old thermostat (one of those round controls where you can only set the temperature to one setting.) I want to install an energy effecient digital control where you have have multiple settings (thus having it cooler at night and while we are at work).

It looks like the old thermostat is just screwed into the wall and I assume is wired to the furnace. Is it difficult to rewire a new control? Does anyone know of any instructions on how to do this? Any brands better than others? Any other tips or advice?
Old 10-13-03, 10:30 AM
Jay11J's Avatar
Join Date: Sep 2001
Location: Rochester, Minnesota
Posts: 18,427
Likes: 0
Received 0 Likes on 0 Posts
The newer T-stat will work with your Oil Furance. Do you have Central Air as well?

If you do have Central Air, you are going to have two(2) set of hot wire.. One hot for the A/C unit, and other for the burner.

You can use off brands from home improvement stores like Home Depot but i would reallly suggest the Honeywell Smart Stat over the off brand if you really want to save, and have comfort.

The t-stat are screwed to the wall and can be removed w/ no problems.. make sure you turn off the power on both units (Furnace, and A/C unit outside)

Make sure you make NOTES of what wire when where on the old t-stat, and hook up the same on the new one.. Chances are the new one is going to have a jumper between RH and RC.. for Oil you remove that jumper, and hook up RH to the Oil burner, and RC to A/C transformer.
Old 10-13-03, 11:37 AM
Join Date: Nov 2002
Location: Massachusetts
Posts: 1,856
Received 1 Like on 1 Post

The thermostat you have is commonly known as the T87, best and most loved, and simple to operate thermostat ever made. If you want an energy efficient savings...the minimum period of on and off(setback) to begin to get a return in fuel savings is 4 hrs. If you don't setback at least 4 hrs, you save nothing. Kill the power to the furnace and AC and remove the thermostat cover gold ring. you'll see a small flat tip screw at about 3, 7, & 9 O'clock I believe...unscrew these and you should have a sub base such as Q539 1147 (provided it's wired for cooling too). Tell us the wire colors comming in to it and the terminals they are secured to. This will tell us a little more about the unit. I take it, this is a heating and cooling thermostat? If this is heating only, it will be much simpler. You said furnace,...this term is generally mis used. Do you have duct work?

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: