Good afternoon
I've just found out this forum, and gain alot of useful experience form posts here. This is realy a wonderful DIY knowledge resource.
Back to my problem, I am going to install an Aprilaire 500M to my furnace and not quite sure some point so i need you guys help. As i read in this forum, A 500M is popular here, i can read about the humidifier part everywhere, but about how to wire into my furnace somehow not sure.
This is my furnace control board diagram.


My thought is :
First , i need 24VAC power source from the board, i suppose it can be from R circuit terminal, is that correct?
Then i need common connection from C circuit terminal?
I need a switch to turn off, on the power to humidifier every time the furnace of, on so i loop the R circuit through Hum dry contacts terminal?
As i found in my furnace manual the instruction diagram like this :


I wonder where should i put the manual controller in the wire diagram, should it be in between the Hum terminal an humidifier or b/w C and humidifier.

 

Welcome to the forums.

I need the part number off that control board to offer help.

 

Control board # A96UH2E. Sorry I forgot list this.

 

That looks like the furnace model number...... not the control board number.

You are just forming a series loop. The components can be in any order or location.
Since it's AC there is no polarity.

 

I don't know how to get the control board part number. Can you show me how.
Above is the control board picture. I see that on R terminal already connected to the red wire to a device I don't know. Is it safe to connect my humidifier power here?

 

These are your thermostat wires......
W1 ------> orange (heat)
G --------> green (fan)
Y1 ------> blue (cool)
C -------> brown (common)
R -------> red (24vac)
You have two C terminals.... a spare one.
You'll have two wires on R. That's ok. More than two gets messy.

I put an arrow in your picture pointing to the board ID label.

 

Thank Pjmax

follow your instruction I got this number F1005
I'll start wiring from the board out of the furnace first to have power source for the solenoid valve first to see. Do you have any recommendation for the wiring diagram?
About the wire color, I don't have any red wire, only black and white. If I use black one to bridge bw R and Hum, there would be both red and black connected to R, will it make any confusion in future?

 

Sorry... that's not the model number.... it's the revision.
Turn my yellow arrow to the left and you'll see a larger white paper sticker.
That should be an Armstrong 103132-03 control board.

I left you the diagram previously. Take a piece of wire and connect R to one of the H contacts.
Connect your outgoing cable..... white to C and red to the other H terminal.
When the burner comes on.... there will be power on that line.

 

You're right. The board number is 103132-03
I'll follow this diagram.
about humidstat, where should be best place to put it : above the return air or in the living room, or any other place?

 

Yes,it works perfectly. Thank Pjmax
a little bit tough when punching hole to mount the humidifier, the res is fine. I connected the house hummidstat at living room instead of following the instruction to put it 6" above the return duct.
Just wait and see if the humidity increase.
Again, thank Pjmax.

 

Good job. You're welcome.

Humidistat in the living area is more effective than in the return ductwork.