Humidifiers and Dehumidifiers - Help me connect this humidistat!

Earlier I asked about a Totaline P110-0009 humidistat.... Well, now I have it in my hands and I'm confused about the wire diagram.

The manual says not to use the HUM terminal on the furnace. Instead, it says to connect the HUM terminal on the Hstat to the W terminal on the furnace.

So the diagram in the manual goes like this: Starting at the humidifier, one wire goes to common (on the furnace) and the other wire goes to H1 (on the Hstat.) Then since the Hstat will be mounted right next to the Tstat, they've got C to C, R to R and Hum (on the Hstat) to W (on the Tstat.)

It doesn't seem correct. When wired their way, you can't humidify unless the thermostat calls for heat, right? When HUM (on the furnace) is utilized, you can humidify with heat or fan, right?

Also, on a sidenote in the manual, it reads: Use of HUM terminal (on the furnace) may cause the heater or fan to run continuously without a call for either.

I'm scratching my head on this one!
If you can help, I'd appreciate it!
Thanks,
Phil

I can't find a drawing on line or a manual at this time.. Unless you have a link.

I have to leave soon, so I am making this short.. Will try to look into it more tonight when I get home from work..

On most furnace, the Hum(d) screws is 120 volts.. you DO NOT want that on the h-stat.

For now, I want to see how this work.. I tried drawing it out of what YOu've said, and not making any sence to me at thie time..

Till tonight, we'll see what we can do!

Jay,
I scanned the wiring diagram, you can see it at this link:
http://mywebpages.comcast.net/o2n/wirediagram.JPG

Thanks,
Phil

Ok, it will work.

Here what's happing.

R on the furnace is your hot 24volts all times. The humidstat is taking power from R on your t-stat to run the display.

C is the common.. The humidstat is tying into the t-stat and common back to the furnace.

W is your call of Heat. When the t-stat calls for heat, power is sent to the furnace to turn on, and also going to the humidstat HUM. If the humidstat needs to turn on the humidfier, it'll make contact and power will go out on H1 to H1 on your humidfier.

With this set up, you won't need a sail switch or the A50 relay.

Jay,
Okay, that makes sense.... but I have a couple more questions.

Currently, the humidifer is energized by a step-down transformer connected to the HUM terminal on the furnace and the exisiting humidistat opens and closes that 24v volt circuit.

If the humidifier will now be energized by the 24 volt source (at W) on the furnace, then there is no need for the step down transformer, right?

Also, is the 24v (W) source on the furnaces circuit board capable of energizing the AprilAire humidifier?

And one last question...with the humidifier energized by the (W) terminal, will it only humidify during a call for heat and not with the fan switch?

Thanks for all you help!!!!!
Phil

there is no need for the step down transformer, right?

Right, you won't need it... Read at the end how I feel.

is the 24v (W) source on the furnaces circuit board capable of energizing the AprilAire humidifier?

Hard to say.. You'll have to look at the max amp rating the transfomer in the furnce itself is rated at.

ith the humidifier energized by the (W) terminal, will it only humidify during a call for heat and not with the fan switch?

Right.


I honestly would use what you have now for transformer, and just run a new two wire up to the humidstat. then wire the the "hot side" of the transfromer to the "HUM" on the humidstat, and then H1 to H1, then H2 to your common side on the transformer.

So, another word, We are not worried about if the transfromer on the furnace is big enough to handel the extra load, and also it will run when you turn your fan "ON" (depends what is used to prove the fan is running)

This is why its best tie the humidifier in to the furnace are say blower all the time .With a A50 current sensing relay and be done with it. That way you can have the hunidifer run any time the blower is on from heat are just fan on.

ED :wall: