Humidifiers and Dehumidifiers - Can't for the life of me get Aprilaire 50 current sensing relay to work

I've tried the neutrals, the hots, everything. Are these things ever defective? I am doing a continuity test with my multimeter and it never seems to activate.

Where do you have this wrapped on? (Blower motor wire?)

Is your blower a standard motor or variable speed?

It's a pretty basic furnace, single speed.

I've tried it on the white neutral for the blower motor, the exhaust blower,

Here's my wiring schematic:
http://img23.imageshack.us/img23/2649/furnaceschem2.jpg

What wire do you recommend I run through the current sensing relay?

You should wrap it around the wire that powers the motor in heat mode.. (Diagram shows blue wire, unless the color/speed has been changed)

Wire can be the basic 18-2 t-stat wire.

You mean the red wire connecting to the round "BLOWER MOTOR" in the schem right?

It needs to connect to the blower that moves the air through the house, not the combustion exhaust blower.

Yes if the red wire is on the "Heat" tap, then you put the relay on that wire.

I've tried it on the blue, red, and white (neutral, which would allow it to run with heat or cool) and nothing. Thing must be defective.

Correct me if I'm wrong - the thing basically works by sensing the power flowing through the wire and completing the circuit on the two leads it provides, right? I've confirmed the red, blue and white wires provide 8 amps but the two leads never have continuity...

Yeah, it is defective.

What are you planning on doing with this? I see you been posting about the IAQ control....

I installed the 700 Aprilaire... I'll see about replacing the sensor relay. Thanks!

I went back and looked at your old post, it was under the IAQ and was confused of what you had.

Did you get the non-stop running issue taken cared of?

Yep - the first A700 I had was defective too believe it or not. I'm not having good luck here :) Such is life, Murphy's Law I suppose. Been too lucky in other projects.

yeah, guess you are not having the luck!

Have you tried wrapping the wires around the clamp a few times?

Got another Aprilaire 50, same result. I figured - WHAT?!?! Must be my multimeter's continuity test, not the 50. Hooked it up with the humidistat's wire, and it works! It was my TEST that was faulty...

I hooked it to the white neutral wire going to the blower. That way, I can run the humidifier summer or winter if need be (and in Colorado, need be with hardwood floors!)

Thanks for all of the assistance, I'm glad to put this one to bed.