# HELP? Control Board Fixed Heat...But Now A/C Won't Turn On - Homeowner



## KLR (Apr 23, 2009)

Hi, Green Newbie Here. Have a Gas Heat & A/C unit combined. Carrier Model 58GEC065-08; Originally installed in 1989; Single phase 115 volt, 60 Hz

I am reading and reading all your great posts but can't find the answer to my problem and I don't know enough to read between the lines. Forgive me in advance if (when) I say anything totally stupid...

I installed a new ICM271 about 6 months ago. :thumbsup:All was great...It fixed my heat & blower perfectly:thumbsup: BUT... I did not think to check the a/c back in the super cold times...:blush: 

well the a/c-condenser fan- doesnt come on at all. My huband was so proud of me for fixing the heat, but now no a/c... We can't afford to call someone out here right now. Hope someone can help me...:detective:

I tested the power when asking for a/c and I am getting 24 volts between y - gh and also y - r. Thats all. Shouldn't I be getting 24 volts between y and gc??

When I ask for heat -everything works great. I checked the voltage so I could post that info too...When asking for heat, I am getting 24 volts between w - c; r - y; w - y; and gc - w. 

Also, my wiring at the thermostat is w to w; y to y; g to g; rc and rH are jumped; and c to b (b is black, I have 5 wires and one is black)

The wiring at the contol board is w to w; y to y/r; gc to gh (supposed to be jumped on the ICM271 control board); r to r; and c to w/b (b - black)

Thanks for any help, Karen 

btw: I bought the board at an appliance website listed on "samurai appliance" website


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## beenthere (Oct 11, 2008)

Your checking for voltage the wrong way.

With teh thermostat set to cool, and set several degrees below room temp, check for voltage from Y to C, and GH/GC to C.

Also, check to make sure that the breaker for the condenser isn't tripped, and is turned on.


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## KLR (Apr 23, 2009)

Hello beenthere, Have seen your postings and much respect for your generosity and knowledge. 

I am sorry that I don't understand what you mean, just too new to all of this...All of the readings I gave were with the thermostat set below what the room temp, by at least 5 degrees; to get the "reaction" of heat/cooling to begin;

also, I did turn on the breaker for the a/c before and again off/on after the testing...sure it is not being tripped.

Thank you so very much for getting back to me so fast...what else can you think of??? Respectfully yours and thanks, Karen


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## KLR (Apr 23, 2009)

*Please be blunt and tell me to post whatever may help*

Please tell me to post whatever you think may help...please be patient with me...Really need help and want/fully intend to follow any direction you give me. Appreciate and thank you for your time, Karen


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## beenthere (Oct 11, 2008)

Take the readings I posted earlier.
The ones you took, are not the correct way. But do give an indication that the thermostat is not sending voltage to the board for A/C.

When the thermostat is calling for A/C, R to Y should not give you a 24 volt reading. But Y to C should.

If you not getting 24 volts fro Y to C, the problem is not the new board, but either your thermostat, or a broken wite, or slight miswire.


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## KLR (Apr 23, 2009)

*Rechecked voltage and connections are secure*

Thanks. I rechecked again with the thermostat set to 10 degrees below the room temp...calling for cool, the results were the same voltage between y - r and y - gh. 

I know there should be no power between gh and y and I need power between gc and c... right? 

I dont know which wires to move on the thermostat or control board to make that happen.

The thermostat is digital. It is a Lux TX9000TS. 

I need help switching out the wiring without killing something or someone. 

I think the problem has to do with the fact that the board has gh gc and the thermostat has rh rc...but I don't know how to compensate for that. Maybe a call to Lux tech support?

I also  double checked for tightness of connections. 

Thanks for your help, Karen


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## beenthere (Oct 11, 2008)

Do you get 24 volts between Y and C of the furnace.


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## KLR (Apr 23, 2009)

*Here is how it is wired now*

Thermostat labels: W Y G RC RH C 

My thermostat wires: W Y G R jump R B 

My control board wiring
from thermostat and two
power wires R and W: W Y/R G jump GH R B/W


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## KLR (Apr 23, 2009)

No nothing between y and c


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## KLR (Apr 23, 2009)

*Trying to get this lined up better*

W Y G RC RH C thermostat color labels

W Y G R jump R B my wires to thermostat

W Y/R G R B/W wires into control board

W Y GC GH R C control board color labels


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## beenthere (Oct 11, 2008)

Thermostat should have a wire(usually red) on RC or RH, with a jumper to the opposite terminal.
Another wire should be on the C terminal(could be black, blue or some other color).
Then a wire on the W terminal(usually white)
One on the G terminal(usually green)
And one on the Y terminal(usually yelow)

On the furnace control board(ICM271)
R terminal should have the wire that connects to the stat RH/RC
Control board R should be jumper to control board GH
Control board W terminal should have the wire that connects to the stats W connected to it.
Control board GC should have the wire that connects the stats G terminal connected to it.
Control board Y terminal, should have the wire that connects to the stats Y teminal, along with one of the wires from the A/C outside unit. 
Control board C terminal should have the wire from the stat that is connected to the C terminal connected to it, along with the other wire from the A/C outdoor unit.

Don't jumper control board GC and GH together.


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## KLR (Apr 23, 2009)

Oh....Then maybe I have to cut the jumper on the control board...the control board has the gh gc jumper "built in". It is called the JW1 jumper on the instruction sheet. The instructions say not to cut this jumper if you have a/c. 

Should I go ahead and cut it anyway??????????8|

Here is the manual's excerpt of confusing instructions:
"The ICM271 has the same features and functions as the current Carrier/BDP replacement (HH84AA020). The ICM271 has additional optional features and some slight operational differences than the older obsolete Carrier/BDP units. These options and operational differences are listed below.
Note: Some older Carrier models did not have a cooling fan relay.
1. On older Carrier/BDP models, the low-speed blower would still function if the 24 volt transformer malfunctions. This will not happen with the ICM271.
2. If the JW1 jumper is cut, a constant low-speed blower will occur without any thermostat signal. Also, a signal applied to the GC or Y terminals will not bring on the hi-speed blower during the cooling mode. *Therefore, the JW1 jumper must not be cut on cooling applications."*

http://www.icmcontrols.com/downloads/icm271_ag.pdf


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## beenthere (Oct 11, 2008)

Sorry. Your correct, don't cut the factory jumper.


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## KLR (Apr 23, 2009)

Here is something even more confusing (to me anyway)...the wiring diagram is different and shows r jumped to gh. Also does it look like the gh gc is cut?? I don't know how to interpret this


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## KLR (Apr 23, 2009)

Wait, I missed what you posted..."Control board R should be jumper to control board GH"!!! I do not have this jumped! :w00t: I am going to go do it right now.

Thank you Beenthere! Oh man I hope this is it...
I'll be back! (after I try it)


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## beenthere (Oct 11, 2008)

The R is jumped to the RH.
The new board should have a factory jumper already. If not, add it.

Although the diagram doesn't show that RC is jumped to RH.
The new board needs it, to use high speed fan for cooling.


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## KLR (Apr 23, 2009)

*Beenthere Fixed It!!!!!!!!!!!!!!!!!!!!!*

:thumbup::thumbup: I am dancing around the house...Dancin, dancin, dancin, she's a dancin machine:thumbsup::thumbsup::thumbsup: 

Beenthere, you are the man! :sorcerer:Thank you! Did I mention how happy I am right now? I already called my husband, he is so happy too.


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## KLR (Apr 23, 2009)

So I did what you said first, jumped the GH to the R put the power back and turned it on and nothin...BUT then after about 90 seconds and the snowflake started flashing!!! and then the condenser came on and it is all fixed and heat & A/C both work perfect! Still no power between y and c but now there is power between c and gh, when calling for the cooling. 

Thank you again, Beenthere. What a great feeling to have that fixed correctly now. Karen


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## beenthere (Oct 11, 2008)

Your welcome. :thumbup:


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## kenmac (Feb 26, 2009)

KLR said:


> Thank you again, Beenthere. What a great feeling to have that fixed correctly now. Karen


 

Did anyone tell you ... He's the man !:yes:


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## kenmac (Feb 26, 2009)

KLR said:


> :thumbup::thumbup: I am dancing around the house...Dancin, dancin, dancin, she's a dancin machine:thumbsup::thumbsup::thumbsup:


 

Can you post a pic of this ??:thumbup:


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## KLR (Apr 23, 2009)

I am so happy right now :whistling2: Company is coming over and beenthere's ears should be burning tonight. Can't wait to tell them about how he helped me fix my HVAC problem. 

Sure I can post pic(s)...maybe too many? can you tell I'm proud? 
Beenthere is my hero, Karen

BTW: Those extra two wires that are wire nutted (first pic) are from the new transformer I put in. They don't make the exact old one I had that only had four wires.


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## KLR (Apr 23, 2009)

Pics did not make it...? Trying again...


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## beenthere (Oct 11, 2008)

Glad to have helped.


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## kenmac (Feb 26, 2009)

still no pics of the dancing machine


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## KLR (Apr 23, 2009)

You are so funny...Kenmac, 
Dancin machine is a private showing, for my husband's eyes only:tongue_smilie:
But Beenthere is my hero!
:shifty:


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## beenthere (Oct 11, 2008)

Dancing


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## kenmac (Feb 26, 2009)

Leo sayer.. Those were the days:yes:


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## KLR (Apr 23, 2009)

I never saw that video before...it is great! Loved it.

Thanks for reminding me, all work and no play make us all dull boys and girls...

http://www.youtube.com/watch?v=FeZ5R3C5bzs


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## larryz (May 2, 2009)

*How to wire a/c control wires to your furance board?*



KLR said:


> So I did what you said first, jumped the GH to the R put the power back and turned it on and nothin...BUT then after about 90 seconds and the snowflake started flashing!!! and then the condenser came on and it is all fixed and heat & A/C both work perfect! Still no power between y and c but now there is power between c and gh, when calling for the cooling.
> 
> Thank you again, Beenthere. What a great feeling to have that fixed correctly now. Karen


Congratulation to your success! I had the same problem as yours. However, you didn't mention how you wire two a/c control wires to your furance board: white wire to C and Red wire to Y? As you mention that there is no voltage between C and Y. How did you wire them? Your information is highly appreciated.


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## KLR (Apr 23, 2009)

The two incoming from the a/c outside are red and white. You can see a good pic of it posted. The furnace board is marked: c y gc gh r w (from left to right). The red from outside is wired to the y of the furnace, together with the yellow wire from the thermostat. The white from the outside is wired to the c of the furnace, together with the black from the thermostat. 

Your wiring colors may be different. 

You need to ask Beenthere any questions you have about this, he is 
THE MAN! 

You are dealing with 220 volts at points inside the furnace...be careful, and post some pics to make it easier for Beenthere to see what you have.


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## rajon (Aug 13, 2009)

Hi, I'm a newb and hope that I am not violating board protocol resurrecting an old thread.

I have a Carrier 58GS050-2 that I replaced the blower motor and controller on. 

My heat works just fine, I have followed this entire thread and the condenser still refuses to come on.

I put the thermostat to cool and see 26VAC across C and Y on the controller board yet the ac unit outside will not turn on. Any ideas?


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## hvaclover (Oct 2, 2008)

Start a new thread. Nobody looks at old threads.


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## KLR (Apr 23, 2009)

You know it always takes almost 2 minutes for my a/c condenser to start up...how long did you wait? 

Carefully go back over Beenthere's instructions...these in particular:

"Thermostat should have a wire(usually red) on RC or RH, with a jumper to the opposite terminal.
Another wire should be on the C terminal(could be black, blue or some other color).
Then a wire on the W terminal(usually white)
One on the G terminal(usually green)
And one on the Y terminal(usually yelow)

On the furnace control board(ICM271)
R terminal should have the wire that connects to the stat RH/RC
Control board R should be jumper to control board GH
Control board W terminal should have the wire that connects to the stats W connected to it.
Control board GC should have the wire that connects the stats G terminal connected to it.
Control board Y terminal, should have the wire that connects to the stats Y teminal, along with one of the wires from the A/C outside unit. 
Control board C terminal should have the wire from the stat that is connected to the C terminal connected to it, along with the other wire from the A/C outdoor unit.

Don't jumper control board GC and GH together. "


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## rajon (Aug 13, 2009)

The only thing I am missing is a "C" terminal on the thermostat otherwise I have gone over beenthere's instructions point by point at least half a dozen times.

I am wired as below:

T-stat -> ICM271 -> Outside
G -> GC
Y -> Y -> A/C
W -> W 
RC-RH -> R-GH
(no term) C -> A/C


Thanks for the reply, I am totally stumped. Do I need a new T-Stat?


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## KLR (Apr 23, 2009)

I feel for you Rajon. :wallbash: 
If I were you I would start a new post in HVAC with "BEENTHERE please help" in the title. Include a couple pics if you can.
Hope you get it fixed, Karen


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