Honeywell HE260A Humidifier install

rdtour

Just purchased the Honeywell HE260A whole house humidifier. I did not feel like buying the "installation kit" for 3/4 the price of the actuall unit.
That means that I want to hook up the humidifier directly to the furnace logic board. I did my research on the logic board (honeywell ST9160B 1050) went to Honeywell's website and found what pins the board uses to talk to the humidifier, "HUM" and "NEUTRAL" bar (duh, me).

Now the HE260A humidifier and humidistat are all operated on a 24vac loop (The installation kit comes with a sail switch (which acts as the on/off part of the loop). My big question is, is the logic board meant to handle that 24vac loop? I do not want to fry my logic board by sending 24vac into those connections, it is not cheap to replace.

***I tend to overthink things and my overthinking is that the logic board is meant to talk to a "smarter" humidifier, a humidifier that is powered as well as have a NO/NC connection that would connect to the logic board.

Otherwise my wiring would be as follows:

24VAC --- humidistat --- HUMIDIFIER --- LOGIC BOARD

--- = 18AWG 2 WIRE

Thanks for your help!
Ryan

hvactech126

those terminals HUM and Neutral bar are 120vac You need a transformer. With the use of a transformer you would not need a sail switch, but would still need a humidistat.

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rdtour

So I need a transformer to connect between my 24vac circuit to the 120vac taps on the logic board? (I have a 24v humidistat and 24vac transformer that came with the unit).
So the circuit would look like this?

Plugin-24VAC pwr source 24v- Humidistat -24v- Humidifier -24v- XFOMER -120V- logic board.

EDIT** Ok so the humidifier system will get its power from the logic board terminals? So that means I take out the 24V power supply and just have the transformer step down the voltage from the logic board, correct???

rdtour

Finished the humidifier and it works. For all you DIYers. The furnace's logic board is the power supply to your unit and humidistat. I just went out and bought a 120/24 vac transformer and plugged the 120VAC side into the HUM and the Common (I had to buy Female disconnects to connect to the board). Then run your power like you would from the wall wort transformer to your humidifier and humidistat.

I bought the transformer at a local HVAC repair place in town. They were happy to sell me a xformer marked up but it ended up being 24 bucks and that is what it cost me with shipping on Amazon. So fair enough.

Hope this helps others in their installs.

rt