Aprilaire 700A humidistat terminal connections for goodman furnace

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Old 01-18-09, 11:24 AM
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Question Aprilaire 700A humidistat terminal connections for goodman furnace

I have installed Aprilaire 700A Humidifier on a Goodman gas furnace.

I am having trouble in figuring out how to connect the W/G and Cf terminals on the humidistat to Goodman gas furnace.

I looked into the furnace wiring diagram.
It has terminals: W R G Y and C.
The terminal C is also marked Humidifier.

The wiring diagram also shows that the humidifier should be connected in the pressure switch, which goes into the Y terminal.

My question is how do I connect these four terminals?
W/G to Y and Cf to C?

Could some one please help?

Thanks in advance.

sk2009
 
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Old 01-19-09, 11:54 AM
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Originally Posted by sk2009 View Post
I am having trouble in figuring out how to connect the W/G and Cf terminals on the humidistat to Goodman gas furnace
W/G should go to the pressure switch.
Cf goes to C on the control board.
R goes to R on the control board.

You can add a jumper wire on the humidistat from C to Cf.

The wiring diagram also shows that the humidifier should be connected in the pressure switch, which goes into the Y terminal.
What mode of furnace do you have?

Y should be tied to Y on the t-stat, and also going out to the A/C unit outside.
 
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Old 01-22-09, 01:18 PM
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Aprilaire 700A humidistat terminal connections for goodman furnace

I have a gas furnace. The humidistat installation manual suggested to connect W/G from the humidistat to W on the furnace and Cf to C on the furnace. But the furnace wiring diagram showed differently i.e. connect to Y. I called Aprilaire Co. Initially they would not answer the question due to liability concerns. But after a little prodding they said connect W/G to W and Cf to C per the manual.

I did these connections after my call. They seem to work fine.

Do you have any comments or concerns about this?

Thanks for your input.
 
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Old 01-22-09, 06:24 PM
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Again, What is the model # of your furnace?

Y is used for cooling, and I can't see why they would do that. I want to look it up.

You could do the W, but some furnace will act up if you "steal" the power from W hook up.

Some will be fine, and others will act up, then you will have to remove that wire.
 
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Old 01-23-09, 10:43 AM
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Aprilaire 700A humidistat terminal connections for goodman furnace

The Goodman gas furnace model # GMS81155CNAA. I am sorry I did not understand that you were looking for model #.

The Aprilaire 700A humidifier has a fan, which is powered separately by 120V power supply. Humidistat is powered by a 24V transformer supplied with the humidifier.

W/G to W connection merely senses if the heat is on and if humidity is low, sends the signal to turn on the humidifier. Will it steal any power from W?

Frankly this is the first time I have ever looked into furnace wiring. I greatly appreciate your help and understanding.

Sk2009
 
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Old 01-23-09, 02:43 PM
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Originally Posted by sk2009 View Post
The Goodman gas furnace model # GMS81155CNAA. I am sorry I did not understand that you were looking for model #.
I looked at your model, and I don't see any wire in the diagram going to Y from the humidifier. Only thing should be on Y is Y from the t-stat, and a wire from the outdoor unit.

I see two HUM.. You have HUM 120 volts you can wire the transformer to for W/G, and C.

or HUM off the pressure switch to W/G, and C to C on the board.



W/G to W connection merely senses if the heat is on and if humidity is low, sends the signal to turn on the humidifier. Will it steal any power from W?
Yes, it going to "steal" power from W to power up (W/G) the fan relay and water valve in the humidifer.

Some furnace act up if you "steal" power from W, and don't.

YOu can try it if you want.. I just wouldn't do it myself.
 
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Old 01-24-09, 11:03 AM
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Originally Posted by Jay11J View Post
W/G should go to the pressure switch.
Cf goes to C on the control board.
R goes to R on the control board.

You can add a jumper wire on the humidistat from C to Cf.


What mode of furnace do you have?

Y should be tied to Y on the t-stat, and also going out to the A/C unit outside.
Jay,

Thank you for your patience.
I am sorry I do not understand your recommendations above.

I suppose Humidistat = t-stat.

Himidistat has R C ODT ODT W/G Cf H H. There is no Y on t-stat.

FURNACE STRIP has W Y R G C

R and C terminals, I connected to the 24V transformer which came with Humidifier.
The 2 ODT terminals go to the outdoor temp sensor.
H H go to the solenoid.

The Cf from t-stat goes go C on the furnace strip.

The question is only about W/G. Which terminal do I use out of W Y R and G to connect W/G from the t-stat?

Thanks again for your help.

SK2009
 
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Old 01-24-09, 11:30 AM
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Originally Posted by sk2009 View Post
The question is only about W/G. Which terminal do I use out of W Y R and G to connect W/G from the t-stat?
Wire the W/G to the pressure switch.

There should be a male termial that you wire a 1/4" female spade onto that.

In your earlier post, you were saying in the diagram you saw you saw hum going to Y on the board.

So that's why was bringing up the Y hook up.
 
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