Help w/ C-wire! New Smart Thermostat & Old Dumb Furnace...

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Old 12-26-15, 11:12 PM
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Help w/ C-wire! New Smart Thermostat & Old Dumb Furnace...

Hey Everyone, pleasure meeting you guys and thanks in advance. I promise i searched online everywhere, particularly this DIY site in and out over the past two days. And have tried to interpret every and any fix or solutions you guys suggested to people with similar problems.

All with no luck thus far. For the new year, I wanted to install a new thermostat to help us with much more consistent and convenient temp control in our house. I picked up an Ecobee 3 after understanding it was compatible with my current set-up replacing an old white-rodgers thermostat.

Long-story short, I was able to pull the old thermosta and realized I only have a 4 wire set-up. I then went to the airhandler, and figured I could install the PEK kit.

No control board anywhere to be found.I searched what I think was every inch of the unit. It looks like I just have a transformer, a couple of switched, and tons of wires.

I figure I need to now pair the right combination of cables to get the unit enough power but dont want to pair the wrong ones.

Can you guys help by looking at my set-up below and suggesting some solid solutions or thoughts?
Any advice you can give before bad weather returns in Atlanta or my wife gives me the third degree would be great! Thanks again in advance!

Quick note:
  • When I plug in the ecobee as is with the wires setup below, it cuts on, and just power cycles through hi, giv me a min, and then keeps going. I assume it's cause it's not getting enough power.
  • When I jump it with an extra wire, from G to C, or RC to RH, it let's me get further, but doesnt do anything and occasionally shuts off.
  • My old air handler unit is a Goodman AWB30-10C. One stage Cool/Heat, no additional accesories.
  • There is a gray cable not being used at all coming from the transformer

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Picture of Air Handler Diagram (Part 1)
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Picture of back of Air Handler
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Last edited by MavStevAtl; 12-27-15 at 12:11 AM. Reason: Attaching pictures
  #2  
Old 12-26-15, 11:44 PM
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Welcome to the forums.

Ok...where are we at......

You've got a piece of four wire telephone cable installed as a thermostat cable.
Can you replace it with a larger cable or do you want to use the extra wire converter ?

These are your connections. if you wipe them off you can see the colors better.

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Old 12-27-15, 12:14 AM
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Thanks for the welcome @ PJmax!

Sorry, I attached a cleaned up version of the wires in the original thread and below.
WTH? Telephone wire? It was here when we moved into our condo unit. Will it be a long-term issue?

I honestly rather use the extra wire converter if it is available. I want to do it myself and won't be able to run wire through the walls. Any additional info or visuals I can help provide?


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Old 12-27-15, 12:30 AM
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Will you no longer be using the A/C for the season... just heat ?

The cable at the thermostat is #22 phone cable.
The cable at the furnace is #18 thermostat cable.
There is a splice someplace in between.
 
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Old 12-27-15, 12:38 AM
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In ATL, the weather has been extremely temperamental. Literally below 50 degrees one day and almost 80 the next, so I will prob need access to both if possible.

I figured they were spliced as the colors dont quite match up, other than green and red wires. The yellow and blue wires from the furnace are unaccounted for at the thermostat. Which I assume were spliced into the black and yellow cable I now see. I can imagine it's either a result of laziness on account of whoever originally set this up or an urgent needs to add additional wiring at some point.

Will it make the smart thermostat set-up impossible?
 
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Old 12-27-15, 12:40 AM
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You need that wire converter now or five wires to be able to use that stat for heat and cool.
You'll need to use your existing stat in the mean time.

Just so you know where we are.

Blue at furnace (yellow at stat) Y - A/C compressor.
Red at furnace (red at stat) R - 24vac
Green at furnace (green at stat) G - blower
White at furnace (black at stat) W - heat


That two wire cable that is connected red to stat blue and white to the heavy blue is the A/C condensor line. That heavy blue wire is your system C wire.
 
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Old 12-27-15, 12:56 AM
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Thanks.
I have the PEK kit that came with the Ecobee, is that what you mean by the wire converter? Should I technically take the 4 wires above at the furnace level right before they go into the wire nuts, and plug them into the kit?

If so, with what wires should I then pair each of the (5) wires (that come out opposite end) going to thermostat and condenser?

OR

Can I run a 2nd wire from the heavy blue/thin red line (going to condensor) over the the Red/Red wire going to thermostat to supplement power (into the wire nut, makes 3 wires in one nut)

*Photocredit: Steve Jenkins install site

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http://www.stevejenkins.com/blog/201...rt-thermostat/
 

Last edited by MavStevAtl; 12-27-15 at 01:05 AM. Reason: To clarify
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Old 12-27-15, 01:34 AM
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You'll remove the four stat wires from the furnace and connect the PKE to the five wires.

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You'll connect the four stat wires to the PKE module.
R = red
G = green
Y = blue
W = white



At the stat end....
Rh/Rc = red (jumper in place)
G = green
Y = yellow
W = black
 
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Old 12-27-15, 09:12 AM
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Thanks. I went ahead and gave it a shot with the instructions you laid out. No luck. I feel I may be doing it wrong.

I powered it on once everything was set, and it did not turn on except for a faint 1 sec hum whn i first flip the switch.

I also read on the mini PEK kit box it said not to use if Cwire is available. On the wire you labeled as "Y", that particular setup was weird as it was a blue (going to thermostat) connected to a red going to a condensor. I connected the yellow out of the PEK kit to the two of them to make a bundle of 3 under the wire nut.

Can you take a look at the set-up below and let me know if I am royally messing things up or need to adjust the wires?


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  #10  
Old 12-27-15, 10:47 AM
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Regardless of the color of the wire Y on the stat should go directly to the condenser along with a common wire, usually from the air handler, at the thermostat be sure an remove jumper between RC-RH,it also looks like you need to connect the yellow and blue/white to the C terminal on the furnace control board,I assume you have this manual.
https://www.ecobee.com/wp-content/up...ationGuide.pdf
 

Last edited by Geochurchi; 12-27-15 at 11:12 AM.
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Old 12-27-15, 02:05 PM
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Thanks @ Geochurchi. At the thermostat, I adjusted the setup back to Rc, G, Y1, W1 only.

I do have the install guide, and it assumes I have a board which I don't. Ive seen that my setup is possible with the best combination of wiring to get it to work.

I tried the pairs you mentioned. Air handler powers up with a hum, but still no power at the thermostat.


On the PEK board (wire from furnace) (Picture further below, showing thick wires plugged into 4 grey slots):
*** Should I swap the thick blue and thick white wire with each other? Or are they ok as is?



On opposite end of PEK board (which takes 4 furnace wires and turns it into 5 wires) (Wires that go to thermostat and condensor):
*** Red is paired with Red to Thermostat.
*** Green is paired with Green to thermostat.
*** White (orange) is paired with white to thermostat.
*** Blue is paired with yellow to condensor.
*** Yellow is paired with blue to thermostat AND red to condensor.

One of the issues I have is that the blue and white wires from the thermostat somehow get spliced to turn into white (Y1) & Black (W1). So I am not sure which one corresponds with which at the furnace end.

Any possible issues I can be running into? I feel like im halfway there now.
And sincere thanks again for your patience in guiding me through this. Extremely helpful!

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Last edited by MavStevAtl; 12-27-15 at 02:06 PM. Reason: Clarification
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Old 12-27-15, 04:50 PM
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You do not have it wired correctly.

Remove ONLY the 4 stat wires. You changed the C wiring. The white from the A/C condensor stays connected to the heavy blue like it WAS. You will now have three wires in the C wire nut.

The red wire from the A/C condensor is the Y wire.

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Old 12-27-15, 05:16 PM
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To understand:

*I should remove the PEK kit all together, all it's wires, and go back to the original set-up I had.
*And THEN add a third wire to the C labeled wire nut.

Which wire do I add to the Thick Blue and Yellow Condensor wire in the C nut to make it three?

[B][

Is that the only wiring I end up changing around?

Since all the wires are paired, it would mean which ever wire I pull to add the the C nut, it's partner wire would be solo.
 
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Old 12-27-15, 05:19 PM
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That is actually white.... dirty white. In the C connection will be the thick blue, dirty white and the C wire to that PEK board.

I have never used that Ecobee board before. I very rarely use the Honeywell version of that board.... but I know it works. I usually just run a new cable.
 
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Old 12-27-15, 05:26 PM
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Thanks!

it is actually a dirty yellow :-). It was gunky before and couldnt quite clean it up enough.

I think I am still missing what you are saying. From which "wire nut" do I pull the C wire to add to the to the bunch? (C Nut that contains, thick blue, dirty white, and XYZ)

*** Pretty much, which wire (out of Y,G, R, or W nuts) in the picture will be my C wire?
Or are you saying I just need to run a new wire?
 

Last edited by MavStevAtl; 12-27-15 at 05:27 PM. Reason: Clarifying wiring
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Old 12-27-15, 05:28 PM
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The heavy blue wire IS the C wire. The dirty yellow is the C connection TO the A/C compressor. Now you need to add the 5th wire of that module to those two wires.

If you look back far enough.... that heavy blue wire is probably grounded to the metal frame of the furnace.
 
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Old 12-27-15, 05:46 PM
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Bear with me, after looking at the above wiring, the only wiring grounded to the frame is the green wire (see picture below).

Does that change my C Wire?
And when you mention the module, are you referring to the PEK kit? or an existing wire from thermostat end of wires in furnace?

Asking as the only way I get the PEK kit to work is to wire the thick BLUE,RED,GREEN, WHITE directly to it.
If I am to wire the thick wires directly back to the original set-up, I will have to remove the PEK kit all together.

What I do have is an unused DARK Gray wire coming out of the left side of the middle transformer as in picture below. Could this possibly be the 5th wire? If so, will connecting it to the C nut going to the condensor provide slightly more power to the Thermostat?

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Last edited by MavStevAtl; 12-27-15 at 05:47 PM. Reason: adding picture
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Old 12-27-15, 06:12 PM
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Focus here.

You have the PEK or board. We're only dealing with one board. You have five white wires coming out of the PEK board. Connect them to the letters I've shown. The C wire on the PEK board goes to the dirty white and the heavy blue wire.

I've given you the four wire colors to connect to the PEK and the four color wires at the thermostat end.

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The red at the transformer is ground and system C. At the relay it gets connected to the heavy blue wire.
 
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Old 12-27-15, 09:08 PM
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PJmax .....

That was a phenomenal breakdown!!! After going back and walking through everything you and Geochurchi laid out. It made sense, and i backtracked on a lot of the wiring to do it all over. Final wiring setup pictured below.

Took some time to calibrate, it was up and running soon after that!
I currently have it only going to Rc, G, W1,Y1. With no jumper to Rh. It seems like it can handle switching between heat and cool automatically through Rc, at least from what i can tell from switching the heating method.

Guys, a huge thanks again for being patient with me and breaking it down. I feel I honestly a little knowledgeable enough to do the install again in our house.

Two issues remain:

*** An existing issue from the first thermostat, when i set it to cool, room temp/barely cool air is coming out. I am going to have the antifreeze checked and refilled if necessary. Or get a tuneup. Hope it's that simple of a fix.

*** Probably TMI. Since this past friday, ive been congested and going through a severe allergic reaction. Woke up in wee hours of saturday morning congested and eyes very iriitated and extremely red almost painful with no home solutions immediately working. I thought it was an extremely bad case of pinkeye at first with all of the symptoms, but after finally visiting urgent care this AM, its a very bad allergy reaction to dust and some other allergens that built up. I honestly assume it was from the HVAC system. So now im on steroids/antibiotics, claritin, and a couple of other items prescribed to combat it. Still very uncomfortable even now.
If it was the HVAC, it was worth it!!!! :-)

Thanks again for everything guys. I am looking forward to lurking around and helping out where i can as i get familiar with the system.

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Old 12-27-15, 09:16 PM
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Awesome news.

Sorry to hear about the dust issues. The dust can be pretty intense inside an air handler.
One thing you can try just to eliminate a stat/PEK issue is when you run the A.C..... disconnect the white/W wire. This will make sure the heating element isn't turning on.

I don't know 100% how the PEK unit works. The Honeywell version has two parts.... one goes at the air handler and the other goes behind the stat.

Get well, Happy New Year and let us know how you make out.
 
 

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