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View Full Version : Any HVAC specialists? I need help!


P-hat_in_Cincy
07-13-2008, 07:45 PM
Hey all,
I hope someone might be able to help.

Today we shut down our AC, turned the fan to 'on', and opened the windows. Sometime within the next hour or so the house started to get real hot. Come to find out the furnace was running! I confirmed everything on the (prog. Honeywell) thermostat was set as it should be, but the furnace was actually firing! I put on the original (non-prog) thermostat and got the same results. The only thing that stopped the furnace from firing was removing the white (heat) wire AT THE FURNACE. If I removed the white wire at the thermostat, the furnace still fired (same for both thermostats).

There's no controlling the furnace portion as long as the white wire is connected at the furnace. It will simply keep running the furnace. If I select the 'cool' mode on the thermostat, both the furnace AND AC will run! Imagine that battle and energy bill!!!

Anyway...Goodman furnace and Honey prog. thermostat. Nothing has been messed with on the furnace except for addition of a humidifier months ago.

Thanks!
Paul

Barritia
07-13-2008, 07:55 PM
sounds like you have a short? you aint been doing any drilling or diy as you could have caused the problem? just remove each colour wire and test for a short between the cables.

P-hat_in_Cincy
07-13-2008, 08:01 PM
Yeah...that's what I thought too, but we haven't touched anything around that area. I'll get out my volt meter.

ogrover3
07-13-2008, 08:28 PM
sounds like a short to me also. the only other thought that i had was the programable tstat more than likely has a setup and you have to tell it that it is either heat pump, straight cool, gas furnace or whatever. but being that both tstats are doing the same more than likely that is not the problem. you should not have 24 volts between red and white. at the tstat if you do then the white is getting power elsewhere check the volt with the wires off the tstat. at the furnace your common off the transformer should not have 24 to the white either. you should have 24 between common and red. careful and dont let any wires touch each other.

one more thought you should check where you installed the tstat and pull the wire out as far as you can out of the wall and make sure none of the bare wires are touching and no cuts anywhere else on the wire.

not sure any of this will help

P-hat_in_Cincy
07-13-2008, 09:08 PM
OK...I disconnected the t-stat wires at the t-stat and in the furnace...so nothing should be connected. I did a continuity check and got the squelch b/w the red and white wires...telling me it's completing a circuit? I guess it shorted somewhere and I'll be pulling new wire.

I'm ignorant when it comes to electronics/circuitry, but I guess I'll be learning.

Thoughts?

P-hat_in_Cincy
07-13-2008, 10:46 PM
Hey all!

Got it solved! Since the t-stat wire had an additional, unused blue wire...I connected it to the white terminals at the furnace board and t-stat. Everything functioned as it should. Therefore, I'll go and get some new wiring tomorrow and run it (should be easy) just to be sure there's no other problems.

Thanks for the replies!
Paul

Mag_Red
07-13-2008, 11:56 PM
Hey all!

Got it solved! Since the t-stat wire had an additional, unused blue wire...I connected it to the white terminals at the furnace board and t-stat. Everything functioned as it should. Therefore, I'll go and get some new wiring tomorrow and run it (should be easy) just to be sure there's no other problems.

Thanks for the replies!
Paulwhy run new wiring if the unused blue wire is doing the job???

P-hat_in_Cincy
07-14-2008, 07:46 AM
why run new wiring if the unused blue wire is doing the job???

I could, but who knows what else might be wrong inside the wall (or where ever the problem is)? But mainly...because of my 'mental disposition'! 8p

It's a trivial run...probably within 15ft and a straight drop right into the basement.