Problems with Carrier Infinity Control and Aprilaire 760

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Old 12-09-07, 08:22 AM
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Problems with Carrier Infinity Control and Aprilaire 760

Hello Folks:

I had a Carrier Heat Pump (Model 25HNA6) with variable speed blower (Model FE4A) installed this past March. A Carrier Infinity Thermostat / Controller was also installed at the same time (SYSTXCCUID01-A). The existing Aprilaire 760 humidifier was kept because at the time installation, it was working fine.

However, the humidifier is no longer working – probably because it was wired incorrectly. The wiring diagram for the humidifier, as installed into the new Carrier system, is below.



Carrier_Hum_Terminal -------> Aprilaire Humidistat -------->Brown Wire on Apriliaire


Carrier_Com_Terminal -------------------------------> Brown Wire on Apriliaire

Aprilaire_Power_plug ----------------------> 120 volt outlet on wall

Note that the 120 volt outlet is just a standard wall outlet near the Carrier unit. It is not part of the Carrier system.

One curious thing is that there is ALWAYS 24 volts across the Carrier Com and Hum terminals. This is true even if turn the Infinity to “off”, i.e., no heating or cooling.

Questions:
1. Is my Aprilaire dead because 24 volts were applied to the brown wires on the Aprilaire ? It’s my understanding that these wires are just a switch that is to be closed only by the humidistat.
2. Why didn’t the Carrier folks remove the Aprilaire humidistat from the circuit and use the Infinity Controller to control the humidifer ? The infinity controller, at least based upon what I have read, is capable of controlling the humdifier. In fact, if I understand things correctly, the Infinity controller has an “auto” mode where it can control the humidity based upon your desired humidity and the outside temperatue. (The heat pump has a thermistor and the temperatue from this outside thermistor is displayed directly on the Infinity Controller in the top left corner.)
3. If I am correct about the Infinity Controller being able to control the humidifier directly, then how do you set it up for this ? It looks like the humdifier configuration should have taken place during the initial equipment setup, but that apparently was not done. At this point, I don’t want to do the reconfiguration myself, I just want to make certain that it can be done. (I no longer trust the installer’s ability.)
Thanks,

RW
 
  #2  
Old 12-09-07, 11:56 AM
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I will have to do some reading on this... I have not done anything with Carrier's Infinty stat.

I;ll post back later tonight after supper.
 
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Old 12-09-07, 08:41 PM
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Looks like the dealer has to read the install manual.

On page 5 of the furnace install manual. it says that a relay must be used on your powered humidifier.

The Aprilaire Humidistat is NOT needed on this, the Infinity t-stat takes care of this for you.
 
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Old 12-10-07, 06:51 AM
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Originally Posted by Jay11J View Post
Looks like the dealer has to read the install manual ........
I know.

This has (apparently) been the most incompetent install job ever done. The main issue was that the salesman stated that there would be no problem installing new Puron refigerant lines between the joists and the removable ceiling tiles in my basement. WRONG.

The installers came out and went "Oh sh**. Not enough room between the ceiling and joists. We will have to rip down your wall" (See attached picture).

Then they had to come back a few days later when the auxillary heating started tripping my 100 amp double pole breaker (never given an explanation on this one, but the problem hasn't come back).

Then they had to come back just after Memorial Day when the unit shut down and wouldn't cool (overcharged with Puron). This one was really great as the unit failed in the middle of a Memorial Day party with ~ 50 guests and temperatures in the mid-90's.... I ended up with one MAD wife !

Now this.

I say it all rests with the salesman who incorrectly scoped out the job. This put the installers behind the eight ball as they lost ~ 4 hrs with taking down the wall and running new refigerant lines. The main installer was at my house from 9 AM to 10 PM. He took only a 10 minute lunch break. The bottom line is that he had to rush to finish things, and when you rush you have errors.

To say I am mad is beyond belief.....

Thanks again,

RW
 
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Old 12-10-07, 07:21 AM
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Yikes...

Do you want me to help you wire up the humidfier right? I'd be happy to go over what you need to do make it right, or you plan on calling the dealer back?
 
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Old 12-10-07, 07:45 AM
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Originally Posted by Jay11J View Post
Yikes...

Do you want me to help you wire up the humidfier right? I'd be happy to go over what you need to do make it right, or you plan on calling the dealer back?
The answer is yes to both questions. I am calling the dealer back (just faxed a description of the problem to them).

And I also want to know how to do it - just so that I know what the dealer is doing when they arrive.

The main thing that is confusing me is why is there always 24 volts across the HUM and COM terminals. Shouldn't this cycle with the demand for humidity ?

Thanks,

RW

PS - I am leaving to go out of town in a couple of hours on a business trip (I'm a mechanical engineer). I will be back late Thursday night, and the dealer is supposed to come out on Friday. So my responses over the next few days may be sporadic.

My background is in heat transfer and fluid mechanics(nuclear power and the paper industry). So I have some novice familiarity with HVAC, but I am by no means an expert. Before I posted my problem description, I searched through a number of the existing posts. I learned a lot by reading your posts to other people's issues.

Your continued comments and suggestions are most helpful !!
 
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Old 12-10-07, 11:36 AM
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Originally Posted by RamblinWreck View Post

The main thing that is confusing me is why is there always 24 volts across the HUM and COM terminals. Shouldn't this cycle with the demand for humidity ?
Carrier_Hum_Terminal -------> Aprilaire Humidistat -------->Brown Wire on Apriliaire


Carrier_Com_Terminal -------------------------------> Brown Wire on Apriliaire
The brown wire from the humidifier is also 24 volts.. so you are reading 24 volts from the humidifier itself! HUM on the furnace is also 24 volts!

I am suprised that is hasn't' burnt/short out the transformer on the humidifier itself or the board since you got power going to each other!
 
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Old 12-10-07, 07:11 PM
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Figured give you an ideal how it should of been done.

 
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Old 12-10-07, 09:42 PM
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Jay:

Thanks for the information.

I suspect that the Aprilaire is fried. I kept the 120 volts plugged in, and then disconnected all the humidistat, furnance, and humidifier wires. Nothing happens when I connect the two brown wires on the Aprilaire. This indicates to me that that Aprilaire is now fried.

Also, with the HUM and COM wires are now separate and disconnected from each other. However, they always show 24 volts no matter what the humiditly control setting is on the Infinity. In fact, the voltage across these two terminals is 24 volts even with the heating and cooling both turned off. Shouldn't the voltage across the HUM and COM terminals only equal 24 volts when there is a demand for humidity ?

Thanks,

RW
 
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Old 12-11-07, 06:27 AM
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Originally Posted by RamblinWreck View Post
In fact, the voltage across these two terminals is 24 volts even with the heating and cooling both turned off. Shouldn't the voltage across the HUM and COM terminals only equal 24 volts when there is a demand for humidity ?
Humm.. Yeah, it should 0 volt when there is no call.. Sounds like that may be fried/contacts welded together.
 
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Old 11-17-08, 08:31 AM
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I have the same problem but mine is wired differently.

Here's my setup.

humidistat------>humidifier (760)------>model 50 relay

Humidistat------>model 50 relay

relay -----> furnace com lead.

Humidifier(120v)-------regular outlet.


Questions:

Is this the correct wiring?

Does the wire need to be stripped to connect to the relay from furnace?

What's the HUM terminal in the furnace for?

BTW, I have a Carrier 92 Comfort Series.

Thanks in advance.
 
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Old 11-17-08, 11:55 AM
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Originally Posted by marlowr View Post
relay -----> furnace com lead.
What relay are we talking about? The A50 relay?
 
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Old 11-17-08, 12:03 PM
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it's GA50 from generalaire.
 
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Old 11-17-08, 04:55 PM
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Ok, we have 3 wires tied to the GA50 relay?

if so, that is not correct.
 
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Old 11-17-08, 07:34 PM
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Old 11-17-08, 08:34 PM
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Originally Posted by marlowr View Post
humidistat------>humidifier (760)------>model 50 relay

Humidistat------>model 50 relay

relay -----> furnace com lead.
Ok, I am having a hard time "reading" this.. are you able to draw or take a photo of your setup?
 
  #17  
Old 11-17-08, 09:38 PM
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Ok, let me give it another try.

The ga50 sensing relay comes with 2 wires on one end and a metal bracket on the other end. The manual says to connect it in a series with the humidistat and the humidifier.

ga50 Relay ----> Humidistat ----> Humidifier -----> ga50 Relay


then attach (with a wire) the metal bracket to the com lead of the furnace.

It doesn't seem to work since the humidifier doesn't turn on when blower starts.

My furnace also has a HUM terminal, is this where I attach the metal bracket? I followed this steps. (powered 760)

http://www.gogeisel.com/geiselonline...stallation.pdf


Thanks again in advance.
 
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Old 11-17-08, 09:51 PM
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Originally Posted by marlowr View Post
then attach (with a wire) the metal bracket to the com lead of the furnace.
Is it the white wire coming off the blower motor? Other than that, it's wired up right.


My furnace also has a HUM terminal, is this where I attach the metal bracket? I followed this steps. (powered 760)
Stay away from that with your humidifier.
 
 

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