Humidifiers and Dehumidifiers - Where is my 24VAC common connection??

Hello -

So here's the story - my humidifier stopped working and I've been troubleshooting the problem... the solenoid is good, the water line is clear, and the humidistat clicks when I turn the dial so I'm assuming that's working too... problem is the solenoid never clicks to let water through. I don't think there's any power getting to it.

I am trying to take it off the add-on transformer and run it right off my furnace board's 24VAC HUM connector. I am sure the hot red wires go there, but I don't really see a place for the white common / neutral wires. There's a blue wire running from a transformer that says 24VAC COM which is what I'm looking for but it runs right from a transformer; can I hook it up right there?

I'd appreciate any advice out there - this is a great forum.

Thanks,

Pete

Can anyone help me with this? I posted a couple lines down... basically my humidifier refuses to click on. I connected the hot wire from the humidifier / humidistat to the 24V connector on my furnace and the common wires to a blue wire that comes from the transformer that says "24V COM" but when I do that, the furnance doesn't start up. It powers up, then powers down, then powers up, and down... in quick succession. The burners never light.

The 110 connection isn't working either and I'm pretty sure the solenoid works. I took it to an ACE hardware store and the guy put the solenoid, which works on either the 24 or 115 connection, right into the wall socket. It clicks just as it should. What am I doing wrong here? At this point I don't care if I waste water and just have a constant stream of water into the pad with the remaining water put right down the drain.

Can someone shed any light on this? Jay, you seem to be the resident expert... is there anything I'm missing here?

Thanks!

Pete

I moved the post into one...

What is the Brand/model of your furnace?

If the board has a 24v HUM, you will not need a transformer.

Then the other wire (Common) goes to C where all the t-stat wires meet up on the board.

It's a ComfortAire furnace with a GeneralAire 1042-LH humidifier... when I connect the red wires to the 24V HUM and the white ones to the common connection, there's a constant clicking sound for a relay or something on the main board. The blowers start up but then power down, then power up again, then power down... the furnace won't fire up. What does that indicate? A short?

I disconnected the 115V transformer that was blown out... I don't know what else it is.

Any ideas?

Sounds like the transformer on the furnace itself may not be strong enough to handle the load.

Does it stop when you take the humidifier off of HUM?

I disconnected the 115V transformer that was blown out.
??? That the humidifier was using before?

Yes - the humidifier was using it before.

Yes - it operates normally if I don't have it connected. I temporarily connected the commons to each other and the furnace operates normally. So, get a new transformer and hook it up again on the 115 transformer?

Yeah, get a new transformer, and hook it back u the way it was before.

Do you have an AMP probe to take a reading on the AMP draw?

... I've gone to three hardware stores and an electrical supply store and nobody can order me or locate an electrical transformer for this. I am going to try to order it from GeneralAire's website unless someone's got a brighter idea...

no one has a 24 volts transformer?? (Door bell can work too)

The problem with the transformer was that it was 12VA. Most doorbells are 8, 16, or 20... or something like that. I couldn't find one to fit it exactly.

I looked up a local dealer in parts through generalaire.com and found a guy that sold me one. After putting it in and connecting it, I realized why the old one went... after about 60 seconds, it got REALLY hot... so there's some kind of short in the wiring up to the humidistat. I hooked it up directly to the solenoid valve and it pumps in water just fine when the furnace is on. Sometime I'll re-run wiring down to the basement and/or try to replace the humidistat. For now, there's water-a-pumpin' again! Woohoo!

Thanks for the advice on the 12V thing, Jay. Happy New Year.

Glad to hear you found one at last, and thanks for the update.

Enjoy the new year!