thermostat wiring to furnace and others.

My girlfriend has had the gas company in a few times and it seems they've been chasing ghosts with her furnace. They told her to replace the control valve on her lennox elite series to the tune of $800.00.

Anyhow, the furnace has been a little fickle for a long time, it would trip in and fire but the blower wouldn't kick in, and it would shut down.

I traced the line from the thermostat to the furnace, turns out it was 4 separate wires spliced together. one splice wasn't taped, hardly touching each other and corroded. In my mind this could cause some of the problems right? EDIT: I did replace the line from the Tstat to the furnace, ran some cat3 cable.

The other question I have is placement of the thermostat. It's in the hallway on the wall right above the furnace room. The wall and floor is warm most times and there's a 3x1 ft cold air return right below the thermostat. Would this have an effect on the rest of the house being colder than it should be?

It's easy to move the thermostat and i'm thinking I may put it in a colder zone of the home... Would this make sense?

 

The wiring should be 18 gauge. If this is a mercury thermostat, pop the cover off & there should be a pointer on a slide this is the heat anticipator. Ideally it should be set with an ammeter but you can try just sliding it to a higher number.

 

The thermostat is an older honeywell with a digital display. I forgot to mention that...

I doubt i'd get an 18 guage wire in there, had a hard enough with the small cat3.

 

Like Grady said you need a 18/2 or with ac a 18/4 wire to the tstat. You dont say what you have there . Could be the board also

 

ok, 18 guage it will be, i'll run that this week. It was a peice of cat3 that was in there so I used the same thing... If you don't know, you don't know right?

What about placement? I'm going to buy a new tstat this week so i'll do all this at the same time. Her current tstat is about 10 years old and was running on shoddy wiring.

Thanks again

 

If the furnace plenum is not insulated, this could certainly have an effect on the thermostat. The upside to it's current location is it is near a major return which should actually help provided you are getting good air circulation.

 

Thanks Guys for your help.

I ran new wiring, 18 gauge solid. Bought a new thermostat too, a NOMA programmable that I got for half price. Left the thermostat in the same place to see if there's a difference.

Will see how things run now.

 

Little update :

Furnace has been running like a charm with the new thermostat and wiring Thanks for all your great advice.


Now I have to move the thermostat, the hallway is definitely warmer than the rest of the house, a full 3 degrees on average and its very noticable. The little remote monitor that came with the thermostat came in quite handy.

If I can only get the girlfriend to wear a sweater now instead of overriding the presets She loves it hot.