Humidifier wiring

Hi,

I have a rheem 90 furnace and an aprilaire 550 humidifier. The humidifier doesn't turn off (water keeps running) when the furnace turns off. It was wired like this from previous owners. There is a wire going from the humidistat to the solenoid wire. The other solenoid wire goes to the furnace transformer. The other humidistat wire goes to the transformer in the furnace. Can someone help me wire it so the humidifier turns off with the furnace?

The transformer is in upper left corner of the pic. I don't see a hum but there is a eac.

Thanks.

 

What is the model # on the furnace?

What control do you have for the humidifier?

 

The furnace is a rheem classic 90. I believe the model # is rcba-3765gg21xi. The control is an aprilaire 884021b that has two terminals on it.

 

I am not able ot find the manual for this furnace..

Look to see if you have HUM on the board.. If you don't then move the wires to W and C.

 

Don't have a hum but do have a eac terminal. When the two wires go to the furnace it ties into a transformer then the transformer wires have wire nuts (blue) connected to it from the circuit board. The white wires are going to another transformer in the upper left and a neutral terminal on the board. The black wires are going to the transformer in the upper left and another spot on the board (can't remember).

What wires do I use to connect to the w and c?

Thx,

Doug

 

since you got another transformer, wire that transformer that the Humidifirer wired to it to the EAC on the board..

 

So do i take the black from the transformer to the eac terminal?

If I just want the humidifier to turn on with the heat do I use one of the wires to the "w" terminal?

The diagram lists a hum in the bottom left list but I don't see it on the diagram. Should it be there?

 

Some board will have the HUM and others won't.

You can keep the transformer and wire it to EAC, and it will come on when the blower runs.

Or

You could take off the transformer and wire it to W and C, but the furnace may act up if you do this.

 

Thanks for your help. I decided to wire it to the W and C terminals so I don't have to worry about turning off the humidifier in the summer.

Doug

 

That will work, and if the furnace starts acting up, then you'll have to bring the transformer back into the picture.

 

Hi Jay,

I read this posting from last year but still have some questions. I am installing a whole home steam humidifer into a rheed classic 90 plus.

The motor on the Rheed is 3/4hp so based on the paperwork sent with the humidifier, it appears that I needed a special fan relay switch (R-8225-B).

There are 5 elements to the install:
1) Humidifier
2) Fan Relay
3) Control board with HUM/EAC
4) Control board with the thermostat controls (W/C)
5) The Humidistat

I went ahead and numbered each of the cable leads and contact points. I would greatly appreciate if you could tell me which points connect to each other. For example :

Wire 1 goes to 3. Wire 2 goes to......


Thank you for your help. I am new to this and the install manual is not very good. Also, do you know if the Rheem Classic 90 Pro runs on 220V or 120V?


The image quality allowed on DIY is not great. So I put all the files and the instructions on dropbox. You can get to it at this link.

https://www.dropbox.com/sh/2ru53g8ybn4jhfy/iFyAshH3cL