[GordL]

I bought a Honeywell HE150 Humidifier to hook up to my Lennox SLP98UHV furnace. I have the humidifier wired up with power, wired to the humidistat placed in the return duct, and wired to the furnace (2 wires - see diagram below). Here's what I'm trying to do now:

1. Have the humidifier force the furnace to blow air when humidity is needed (like, right now - we haven't had a humidifier for a month and the air is very dry).
2. Have the iComfort thermostat control the humidifier (if possible).

My equipment is as follows:
Honeywell HE150 Humidifer
Lennox SLP98UHV furnace
iComfort Thermostat (back of it says "Cat 49W95" and "Rev 0120/16000")
Lennox A/C (not sure the model number, but it's old... about 18 years?)

Here's a diagram of my wiring so far. I don't have the outdoor sensor wired to the Honeywell humidistat at this time (not sure if it's needed, and it means rooting around under my porch in the winter). I've also drawn in some of the other wires to the Lennox board, such as the outdoor sensor, and the Lennox A/C unit. The iComfort has 4 wires coming from it: Red (R), Green (i+), Black (i-) and White (C). In the diagram attached the white wires are drawn in grey to make them easier to see). I don't know what the black and white wires coming off Y1 and C are on the board - the installers put those in. Power to the humidifier comes from the 24V transformer included with the humidifier.

If anyone can provide assistance it would be greatly appreciated. Here are links to the manuals:

Lennox SLP98UHV Installation Instructions
www1.lennox.com/pdfs/installation_maintenance/Lennox_SLP98UHV_IOM.pdf

Honeywell HE150 Installation guide
customer.honeywell.com/resources/techlit/TechLitDocuments/69-0000s/69-2413EF.pdf

Link to wiring diagram:
s9.postimg.org/6pdbpzgfj/Lennox_Honeywell_Wiring.jpg

 

[djlandkpl]

I have an slp98v with an XP25 HP. It comes with an outdoor sensor.

All of the wiring connections are done at the furnace. There are settings in the iComfort that let you control the humidity. If you want it to automatically change the humidity according to the outdoor temperature you need an outdoor sensor.

You can't use the 4 thermostat wires to control the humidifier. You should also be able to power it directly off of the furnace.

 

[GordL]

Sorry, Dan, I guess I wasn't clear enough in my writeup.

I have an outdoor sensor hooked up to the furnace, just not to the humidistat that came with the humidifier. The information about the wires coming from the iComfort were just to complete the information about all the items I have (they obviously run to the furnace).

What I'm looking for is help with wiring the humidifier to the furnace in order to allow the iComfort to control when the humidifier turns on and off, and so that the furnace blows when the humidity is too low.

If you copy/paste the wiring diagram (the last link) you can see how it's currently wired. I can't do a direct link, as I don't have enough posts on the forum.

Thanks,
Gord

 

[yuri]

You don't need an additional 24 volt transformer for the humidifier. You can use H and C on the terminal strip. The IComfort will control the humidity and you don't need a humidistat. You may have to go into it's settings/Menu and tell it to do it.

Not sure if the IComfort has ON demand humidification but you can turn the fan to ON and it will run at low speed (40%) and that should help. There is no way to cheat using G as you have a communicating thermostat. Also that would turn on the low anyway.

With a modulating furnace running the fan ON for circulation and added comfort is the best way to run.

Y1 and C are necessary for your old school AC.

 

[GordL]

Thanks, Yuri.

I wasn't sure about needing the 24V transformer, but I decided to install it anyway since I wasn't sure where to wire it from on the board. It works now, so I'm not concerned about it.

So, should I just disconnect the humidistat that came with the humidifier?

 

[djlandkpl]

Thanks, Yuri.

I wasn't sure about needing the 24V transformer, but I decided to install it anyway since I wasn't sure where to wire it from on the board. It works now, so I'm not concerned about it.

So, should I just disconnect the humidistat that came with the humidifier?

You don't need the humidistat. The iComfort will turn it on when needed.

 

[yuri]

Yep it is quite inaccurate and the IComfort will do it. Check the menu to activate it.