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Hello, my name is Billy.
I hate to give conflicting info but it is NOT recommended to wire the humidifier into the gas valve circuit.
Also we will need to know humidifier maodel number as some Aprilaire units use their own built in transformer which would conflict with HUM terminal.
So, what model humidifier?
What wiring was used before to humidifier?
And yes you are correct...we should not need a current sense relay.
Ok, you have a basic flow through with a simple 24v solenoid.
Now there are various ways to wire. The most common is HUM and C..
The hum goes to humidistat
out of other humidistat terminal to solenoid and from remaining solenoid wire back to C.
As a test..turn power off..
Run a wire from R and C..
Attach R to one solenoid wire and C to to other...the solenoid should react as it will have 24v constant.
Then we can go from there
no problem...just wait until you can attempt and then respond.
Keep this on your end as any response from you forces a response from me.
Hum = operation in heat mode.
We do not want W terminal as that puts it in the same circuit as the gas valve. Basically this adds another "load" in the gas valve circuit.
The HUM is dedicated circuit for humidifier. To wire in the W (gas valve circuit) would work but is strongly frowned on as it can affect the heat circuit.
Ask anything you need to know...
please post pic of the humidifier here with front off.
Hello, Billy has opted out of the question so now I can help you again. Have you tried the original diagram that I sent you? ( Sorry you are getting conflicting information here - Aprilaire specifically gives you the option to use the w terminal because the solenoid has a very low volt amp rating)
If you are blowing a fuse when the humidifier is turning on, you have a short in the humidifier circuit. Recheck all of the wiring and make sure there are no nicks in the wire jacketing too.
IF all wiring is good - when Billy had you run a pair of wires from r and c to the humidifier, the fuse blows then the solenoid valve itself is suspect of the source of the short.
And the new one is blowing the fuse?
Okay. Did you run all new wiring to the new humidifier? If any piece of the wiring is skinned or touching the ductwork or both wires touch each other it will ground out and short. It's most common to find a short in the wiring from a bare spot touching metal
I see the picture you sent of the furnace circuit board, is this a Bryant/Carrier/Payne furnace? Also a picture of the humidifier and the humidistat would be really helpful.
can you send me a picture of the humidistat with the cover off and a picture of the humidifier with the cover off?
I know these shorts are trying, but we will get it straightened out
The diagram you followed is correct for a conventional humidifier and humidistat like the Aprilaire 400m with dial humidistat. We need to be certain there are no shorts in the wires themselves.
Okay got the pictures. Can you send a picture of where the wires splice into each other? ( I see the humidistat is wall mounted and has a red and white wire to it, and the solenoid has two white wires to it)
Unfortunately I'm not set up for phone right now. If you want to wait until you can get more fuses that's fine with me. Just so you're not out of heat for the night
Okay, so the white wire goes straight to the solenoid valve, and the red goes up to the humidistat and back from the humidistat to the solenoid valve?
Do you have a volt meter available?
That's exactly how it should be. Try this one more time - turn off power and disconnect humidifier wiring from solenoid valve and circuit board. Run one wire from c terminal to one leg of solenoid valve. Run one wire from r terminal to the other leg of solenoid valve. Restore power and listen for the solenoid to click. This will verify the solenoid valve is not shorted (I know it's new but I've seen it before)
did it blow the fuse?
Okay, that verifies that the solenoid is good. Now, that also tells us there's a short in the wiring somewhere.
Okay let's try this... Turn off the power, Replace the wires as they were, disconnect the wires from the humidistat on the wall. Take those wires at the humidistat and tie them together. Restore power and see if fuse is good when the runs (solenoid will click then too when heat comes on if the fuse doesn't blow). This will tell us if the humidistat is causing a problem.
Very doubtful but this is the only way to troubleshoot without a volt meter
Can you send a picture of the humidifier without the filter panel in? Do you have those white wires that the diagram shows?
So it's not the humidistat. And you have it wires exactly like the diagram shows with the white wires? (That is an overflow switch in the bottom of the unit)
Try taking the white wires out of the sequence.
Just to verify the overflow switch isn't causing the issue (doubtful again). I'm definitley positive there's a short in the wiring - we've proved that. What I would suggest is running new wiring from the furnace to the humidistat and back from the humidistat to the humidifier. There is a short, somewhere
Its very hard to tell without a volt meter to check continuity with
Try the wiring before calling for someone to come in. I'm confident that will save you $$$!
When you have time of course. I'll be hear waiting to hear if you got it! :)
Awesome, I knew there had to be somewhere
Probably a small pinch that you can hardly see
For sure! That's what I'm here for