Honeywell Visionpro IAQ and EIM wiring Help, AC not working

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  #1  
Old 04-26-09, 06:24 AM
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Honeywell THM5421C EIM and TH9421C1004 Thermostat HELP! no AC

I recently installed an Visionpro and EIM and am having trouble, I have a basic setup with an American Standard 3 wire furnace and an older Carrier 2 wire A/C. I have had no issues with the heat but I went to turn on the A/C last night nada, the fan came on but nothing else, I went and hard wired the A/C to kick on te compressora and make sure there were no issues and it came right on, I am really confused. This should be straight forward.....any ideas?


Current Setup
THM5421C EIM
TH9421C1004 Thermostat
American Standard Freedom 80 Single Stage
Carrier 38EN030340 A/C
Aprilaire Model 760 Humidifier
 

Last edited by BradGo; 04-26-09 at 07:45 AM. Reason: adding details
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Old 04-26-09, 06:17 PM
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No help??? This is really setting me back?
 
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Old 04-26-09, 07:34 PM
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You have Y1 wired to Y on the furnace, and a wire from the outdoor unit meeting up on Y at furnace? Also the second wire from a/c should go to C on the furnace.
 
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Old 05-22-09, 10:34 AM
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Y to Y2 connection

Wasn't sure whether to start a new thread or not, but here goes.

I have a similar problem with a new install, I have the Vision Pro IAQ and EIM with a single stage Goodman SSX140241A A/C.

The IAQ is set up for a single stage compressor,

0172=1
0174=1

The indoor temp was 24C, so I selected cooling on and a target temperature of 18C. Indoor fan came on but not the A/C. I checked the Y connection at the EIM and got 4.6V AC, interestingly the Y2 connection had 26.2V AC.

I then reset the thermostat to a target temperature of 23C and the A/C kicked on Y had 26.2V AC and Y2 4.6V AC.

Now I can (kind of ) see the "logic" here if this was a two stage unit, the demand for the six degree drop may require both stages (of a two stage A/C), whereas the requirement for a 1 degree drop can be handled by 1 stage. However the system has been programmed to tell it the A/C is single stage. I guess a work around would be to jumper Y - Y2, but why is Y2 even in the equation?

The other question this raises is why is there a 4.6V on Y or Y2 when it should be 0. I assume that the relays are mechanical and not solid state?

Wooly
 
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Old 05-26-09, 07:44 AM
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double check your settings. I have run an IAQ in single stage mode before and did not have your problem.

if you want someone on here to give you a full verification, post your wiring connections and all your IAQ settings.
 
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Old 05-27-09, 05:35 PM
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Thanks for the response, I'll get the info together and draw up a diagram for posting.

One additional question, not directly related to the original; The Y terminal on the EIM currently connects to the A/C unit only, should it also connect to the Y terminal on the electronics board of the Goodman GKS90703 furnace

Wooly
 
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Old 05-27-09, 10:01 PM
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The relays are solid state and 4.6 V is normal for an "off" state. Y from EIM runs to furnace Y and to compressor from there.
 
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Old 05-28-09, 06:17 AM
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Thanks for the response zoneout, it's all coming together slowly

Wooly
 
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Old 05-28-09, 06:31 AM
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Originally Posted by wooly View Post
Thanks for the response, I'll get the info together and draw up a diagram for posting.

One additional question, not directly related to the original; The Y terminal on the EIM currently connects to the A/C unit only, should it also connect to the Y terminal on the electronics board of the Goodman GKS90703 furnace

Wooly
Yeah, the furnace needs to know if it is operating the fan for the compressor, heat, or just constant on. So signals for all of those have to reach the furnace. The same thing applies for a 2-stage A/C or heat pump. Both y1 and y2 have to be connected to the furnace board.
 
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Old 05-28-09, 10:53 AM
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Fixed?

Thanks for all the repiles, Y is now connected at Furnace and EIM. I also had the power off today at the furnace and EIM. When I powered back on I decided to retry the A/C test. I took the required temperature 3 degrees below the room temperature and this time Y energised and Y2 did not (expected behaviour). Not sure if any gremlins got in there or what
 
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