# [SOLVED] Heat not working...Thermostat wiring issue?



## mwkrei2

Hello all, first time posting. I have an issue with my thermostat, I believe. I replaced my old one (don't have it anymore, but it was one of the one with the two mercury bulbs and the sliding adjuster), with a Honeywell RTH2300/RTH221 Series. I connected the wires the best I could and the A/C worked fine, but now it's gotten cold in Florida and I tried to turn the heat on but it did not work

I'm pretty sure I have an electric furnace and have otherwise setup the thermostat properly (I think), but the heat will not turn on at all. I believe I have wired the thermostat wrong and some of the wires don't match up with the thermostat. They are currently as follows:

B --> Empty
O --> Orange wire (originally labeled O)
G --> Green wire (originally labeled G)
Y --> Yellow wire (originally labeled Y)
W --> Empty
NOT USED --> Empty
R --> Red wire (originally labeled R)
RC --> Jumpered from R

And three extra wires:

A baby blue wire originally labeled C --> electrical taped off
A brown wire originally labeled E
A white wire originally labeled W2

The handler has wires running everywhere on the inside, but I'm happy to look out there if anyone needs it.

Help would be greatly appreciated, as it is surprisingly cold down here. Thanks!


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## Wrench97

*Re: Heat not working...Thermostat wiring issue?*

W turns on the system, usually goes to a relay

G turns on the fan (Green or Gray)

Y turns on the A/C (if equipped) (usually with W1 and W2 you would have Y1 yellow and Y2 Blue )

RH is the feed wire from the 24v heating transformer (red)

RC is the Feed from the A/C transformer (red)

But with a O or Orange wire it sounds like it may be a Heat Pump?

O energizes the heat pump reversing valve in cooling mode

B energizes the heat pump reversing valve in heating mode (brown)

W1 White Energizes First Stage Heat

W2 Black Energizes Second Stage Heat

The electric back up would be the second stage heat.


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## mwkrei2

*Re: Heat not working...Thermostat wiring issue?*

Right, so isn't it weird that there is only a W2 wire and no other W wires?


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## Wrench97

*Re: Heat not working...Thermostat wiring issue?*

Yes unless the system has been modified from the original set up, or you may not have a compatible thermostat see if you can find the black wire at the unit if its on the heat side it may have to go to the W terminal on the thermostat.


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## mwkrei2

*Re: Heat not working...Thermostat wiring issue?*

I wouldn't doubt it that the system has been modified over the years. I apologize for my naivety but I have no idea about wiring on the unit. Best I can do is shoot a couple pics from the handler


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## mwkrei2

*Re: Heat not working...Thermostat wiring issue?*


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## Basementgeek

*Re: Heat not working...Thermostat wiring issue?*

I think you need a HVAC expert to sort this out. Wire colors do get switched.

BG


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## mwkrei2

*Re: Heat not working...Thermostat wiring issue?*

I figured that may be the issue. I was hoping it was a simple wiring mistake on my end at the thermostat. Thanks for the help.


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## Wrench97

*Re: Heat not working...Thermostat wiring issue?*

Yea that looks like a lot of mixed equipment there, unusual to see the heaver gauge wires hooked to the lighter gauge thermostat wires.


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## Vegassparky

*Re: Heat not working...Thermostat wiring issue?*

Is there a schematic on the back of the sheet metal cover from the equipment? It looks like the unit is equipped with electric reheat.


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## Vegassparky

*Re: Heat not working...Thermostat wiring issue?*

It also looks like there are two thermostat cables in your second pic. Where do each of the brown sheathed cables go? Also, this is a split unit, (evaporator/fan inside, and condensing unit outside)? The cable on the left of your second pic looks like it goes to the condensing unit, as it's run with the lineset.

Your stat will work, just have to get it all sorted out.


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## mwkrei2

*Re: Heat not working...Thermostat wiring issue?*

There is a schematic. I'm trying to upload pictures now. And yes, it is a split unit, evaporator/fan inside and condensing unit on the roof. And yes, I think the one goes to the unit on the roof and the other goes down south somewhere, there's a wooden box that the handler sits on, but I have no access, so I don't know where it goes. And the third brown sheathed cable on the far right in the middle of the second pic goes to the thermostat (I'm assuming).


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## mwkrei2

*Re: Heat not working...Thermostat wiring issue?*


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## Vegassparky

*Re: Heat not working...Thermostat wiring issue?*

It's still a bit difficult to tell(see note 4), but it looks like the white W2 stat wire should be landed on the W terminal of your stat. That should be coil voltage for the heater relay. The brown is connected internally because you only have single stage heat, so make sure it's safed off before you turn the system back on. The internal wiring looks like it will run the blower when the heat is called for. Make sure it does. Check to see if the outside condenser is also commanded to run. The condenser shouldn't run if it's not a heat pump. I don't think you have a heat pump, as I don't see a reversing valve on the diagram. But then again, the orange wire is hooked up, so it's possible. 

FWIW, the E(mergency heat) wire typically will only run the blower and electric heat without the condenser. That is in case the condenser has frozen up/failed.


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## Vegassparky

*Re: Heat not working...Thermostat wiring issue?*

One more question, the brown cable you said goes down, what is it connected to? From the pics I can only see connections from the cable from the condenser, and the one on the right that you think goes to the stat?


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## mwkrei2

*Re: Heat not working...Thermostat wiring issue?*

When you say make sure the brown is "safed off", how do you mean? I'm not very tech savvy. And how do I know if the condenser is commanded to run?

So I should leave everything as is and connect the W2wire to the W port on the stat?

I have no idea where the one goes below. It goes under the handler. It's on a solid wood platform with no access panel.

I truly appreciate your help with this. Thank you.


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## Vegassparky

*Re: Heat not working...Thermostat wiring issue?*

No problem. All your other wiring looks correct. The cable going below, what color wires are connected, and to what, in the second picture? If it's black and red, that may be doorbell power or something.


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## Vegassparky

*Re: Heat not working...Thermostat wiring issue?*

Safed off with a wire nut is best, like any unused wires. Electrical tape works temporarily, but can eventually fall off and cause a short. And yes, white W2 to W on stat should run your heat. Take note if the condenser is running when you are in heat mode.


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## mwkrei2

*Re: Heat not working...Thermostat wiring issue?*

It's a pink and red wire that run below. It looks like the larger pink wire is jumpered to a larger yellow wire. You can see it in the 1st pic on the thread. I tried to turn it on and there is nothing. No sound from the handler and no air blowing from the vents.


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## Vegassparky

*Re: Heat not working...Thermostat wiring issue?*

I know it's late there, and you're probably tired. Remember to keep careful, and turn things off before you work on them. I'm still looking at the schematic, and not seeing anything different. Do you mind taking a picture of the stat terminals and all the wires, connected, or not?


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## mwkrei2

*Re: Heat not working...Thermostat wiring issue?*

Yup. I've been turning off the breaker each time. This pic was before I connected the W2

http://imagizer.imageshack.us/v2/800x600q90/46/32vuv.jpg


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## Vegassparky

*Re: Heat not working...Thermostat wiring issue?*

When you tried to turn on the heat, how long did you wait? The drawing shows a blower time delay relay, and you may have to wait a little longer for it to close(usually within 10 minutes or less). That is for protection of the motors from short cycling(quickly turning on/off).


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## Vegassparky

*Re: Heat not working...Thermostat wiring issue?*

It's also possible the heater relay has gone bad. They are very reliable, but do fail. I won't advise you how to troubleshoot that unless you're proficient with a voltmeter.

The questionable relay I circled in green.


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## mwkrei2

*Re: Heat not working...Thermostat wiring issue?*

I'm not proficient with one. I suppose I will get an HVAC expert out. Thanks again for all of your help.


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## Vegassparky

*Re: Heat not working...Thermostat wiring issue?*

You will have to call someone in, unfortunately. Field testing has to be done at this point. The mystery wire going down below may be a safety interlock, and/or that relay may have failed. A competent tech will have it running in no time.


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## mwkrei2

*Re: Heat not working...Thermostat wiring issue?*

Happy to report it's fixed. It was a blown fan capacitor and a blown fuse. Thanks again for the help.


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## Wrench97

Good to hear you're in the heat


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