Humidifier Wiring Help

I am going to be hooking up an Aprilaire 700 to my ComfortMaker N9MP1 furnace and have a couple of questions. The attached image is the wiring diagram for my furnace. When hooking this up, the wires from the Humidistat to the furnace (R, C, G, W), seem pretty easy.

The questions I have are regarding the yellow wires from the humidifier:

1. Am I going to need to use the 24vac transformer?
2. Would I use either the HUM or EAC on my furnace control board?
3. If I use the 24vac transformer, where should I get the 110vac from?

Needless to say, I am asking questions this time before I attempt to hook it up. The first time I attempted an install on this furnace, I cooked the Humidistat.

I am using the basic, programmable thermostat with this.

Thanks in advance!

Mike

 

So I decided to do some testing. Here is some of what I found.

The HUM, is 110vac, on only when the furnace is running.
The EAC, is 110vac, on only when the fan is running.

So knowing this, I would assume that I would need to use the 24vac transformer. Is this correct?

Also, since the HUM is only on when the furnace is running, could I technically wire the transformer to the HUM and the HUM-N to get the 110v to the transformer or should I wire it into a dedicated 110v circuit?

I am trying to figure this out on my own without bugging everyone. Some simple confirmations should resolve this and send me on my way!

Thanks in Advance!

 

You'd need the transformer. if you wired this to it, the display will come on and off w/ the heat cycles.

Wire the transformer to a source that has steady power.

 

Thanks for the reply Jay. So if I hook the transformer up to a constant power supply, with the unit still shut off when the furnace does or will it continue running?

Is there a better way that I should be wiring this?

Thanks again for the help.

 

Yes, wireing the transformer to a constant power is fine. The W wire will tell when the furnace is on and off.

 

Thanks a ton Jay! I will let you know how it turns out.

 

When piping the bypass, can you have two 90 elbows?

Where I have to put my humidifier, my only choice is to use an elbow to go around the corner of my furnace and another elbow to go into the return. Most diagrams that I have seen only show one elbow.

Thanks!

 

Yes, you can use more than one if you need to make it work.