# Thermostat Wiring & Troubleshooting guide



## mdshunk (Dec 4, 2005)

Red, 24Vac
white, energized on call for heat
yellow, energized on call for compressor to run
green, energized for fan to run (cooling only, normally.)


Troubleshooting guides? They don't really make them for specific models of furnaces, since the same skills and procedures apply to many brands and styles.


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## #CARRIERMAN (Oct 18, 2006)

Hi Hippie

To start off with I will give you the nomenclature for the wiring.
R= 24volt hot, normally red
W= Heat output, normally white
Y= Cooling output, normally yellow
G= Blower output, normally green
C= 24 volt neutral, could be blue or black

Now to the second part of your request, if you let us know what the furnace is doing or not doing we can probably walk you through the repair. As far as a troubleshooting guide. Your furnace is either a Heil, Termpstar, Comfortmaker, Etc. If you type the type of furnace into the search bar, It should produce something you can follow from there.

Good luck
Rusty


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## Hippie (Nov 19, 2006)

Thanks for the info so far...

As for the model, it is a comfortmaker.

I haven't really checked out what it is/isn't doing... I just moved in and my cousin asked me to check it out. This furnace is used to heat a 2 car detached garage and apparently he just realized one day it wasn't engaging. He wasn't sure how long it hadn't been working. So I figured I'd start by making sure that the thermo was calling for heat, then trace my way through from there. 

FWIW, this is a propane fueled furnace. The fuel supply is 3/4 full, and the valves are open. The unit seems to be getting power, as I heard some clicking when I was flicking a open/closed switch for an access panel, though I didn't put a meter on anything to test it as I was just giving it a once over looking for broken wires / connectors etc.

I'll type more as I look in to it


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## Hippie (Nov 19, 2006)

*Problems solved*

As I looked into it, I found the 2 problems in the system. the low voltage wires at the controller on the heater had 2 wires that seem to have been corrupted, as touching them ever so lightly they seperated from the controller. After reattaching the wires, I jumped the controller at the T-stat connection, which engaged the heater. Next I removed the T-stat and jumped the 2 wires (turns out that it is a heat only T-stat), which worked, so I replaced the T-stat, and all is well.

Thanks for the info Guys... 

Carrierman, you seem pretty busy here, keep up the good work


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## david barfield (Oct 20, 2009)

#CARRIERMAN said:


> Hi Hippie
> 
> To start off with I will give you the nomenclature for the wiring.
> R= 24volt hot, normally red
> ...


i have a electric heil hvac. i turned the furnace on the other morning and noticed the a/c compressor was running at the same time. i pulled the fuse from the compressor and the furnace seems to work fine. i suspect a wire is crossed at the thermostat - any idea which one?


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## #CARRIERMAN (Oct 18, 2006)

Hi david barfield

My first question would have to be do you have a dual fuel set up. This would typically be a heat pump outside with a gas back up inside. If your answer is yes I would say you are probably fine. If the answer is no and you have recently installed a new digital thermostat. You will need to set the mode switch inside of the thermostat to the gas mode, I would say that the later is the more likely and you will find the internal mode switch set to electric. Let me know if I can help any further as you can tell by my profile I work for the railroad now. I don't get much home time, but I still love to help when I can.

Good luck
Rusty


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## Plumber101 (Feb 25, 2009)

david barfield said:


> i have a electric heil hvac. i turned the furnace on the other morning and noticed the a/c compressor was running at the same time. i pulled the fuse from the compressor and the furnace seems to work fine. i suspect a wire is crossed at the thermostat - any idea which one?


 
Sounds like a bad thermostat

Remove stat and jump R & W then see if the compressor is running if not replace the stat


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