Aprilaire 560 to Goodman GMP100 Wiring Question

[knappy1]

I have an Aprilaire 560 installed on a Goodman gas GMP100 furnace that was installed (massively incorrectly) by the previous owner -- the humidifier has not been operational since we moved in. I have figured out most of the issues with his botched install -- including the fact that he's missing the solenoid all together -- and have ordered the replacement parts to make it work.

Now for the wiring -- the furnace has a dedicated 24v HUM location that I believe would be wired to "R" in the humidistat, and both wires from my new solenoid will route to the "H" locations in the humidistat (yes?), however I cannot figure out the 24v "C" or COM location on the furnace panel (there is nothing marked as COM or C on the furnace panel or wire diagram) -- Is it my thermostat "W" or is it the 24v "BL" at the bottom left of the board (I don't know what it does)? Additionally, the other guy has the A50 circuit detector installed -- don't know what he thought it was doing without a solenoid, but it is redundant with the HUM location, correct? If I wire to the HUM I can remove the A50 altogether, right?

Any help would be appreciated!

Thanks,
Knappy1

[Jay11J]

For your furnace, you wire up this way..

Humidistat--------Furance
R-------------------R
C jumper to Cf----C
W/G---------------HUM


Two wires from humidifer goes to H.

The A50 won't be needed.

Make sure the MODE switch is set to "A"

[knappy1]

Thanks! When I get my new solenoid I'll try it and let you know how it works.

Knappy1

[Jay11J]

Glad to help, let us know if you have any questions.