Looks like it would have to be tied into the supply trunk coming off the front of the plenum if there is not enough space to run a 6" round duct around the back side of the furnace. Yes this would take some air away from whichever portion of the house this trunk feeds (technically that would happen if the bypass were tied into the plenum itself, though). Sometimes that is the way it has to be done given space constraints. Of course you will just make sure it is installed in a way that does not block service access to the coil, etc. Humidifiers can be a great addition to a system; I know I like mine (which is installed in somewhat of a similar fashion, by the way). Proper maintenance is paramount with them however (making sure the drain tube doesn't become obstructed with mineral buildup, changing the water panel regularly, cleaning the enclosure as needed, etc.).

This post was edited by ryanhughes on Sat, Nov 30, 13 at 14:59

You have an interesting gas supply connection. You seem to have copper tubing feeding a combination black pipe and brass fittings. Who put this together? I don't think any of that is compliant with the plumbing code. It should be replaced with black pipe or the very least flexible tubing rated for gas.

It is probably (hopefully) LP as opposed to natural gas.

This post was edited by ryanhughes on Sat, Nov 30, 13 at 18:21

There is room behind the furnace after double checking I could tie it into the lower area. The only issue with that is the coil. Is it possible to install there or not a good idea? Otherwise I'd have to install it at the horizontal duct above the register?

The house was built in 03 I'd have to believe the gas lines passed an inspection we are running natural gas.

I would not install it on the backside of the coil enclosure. You would most likely get poor airflow through the bypass that way. Is it not possible to bring the bypass to the top-back side of the plenum (just above the coil and directly behind the area where the white vent is pictured)?

As for the gas line, it depends on the jurisdiction and codes for that particular area. In many areas copper tubing is not allowed (due in part to the corrosive nature of NG over time). You would hope a proper inspection was done after the house was built. If this home is in a subdivision, presumably all of the installs were done this way.

That's where I wanted to put it after looking behind. The only problem is a metal bracket that's in the way a little bit. I'm thinking I should just shave the starter collar flange on the top and bottom a little to get the room. My next question is wiring up the unit. I have hum and neutral on my circuit board for the furnace. Is there a way to not use the stuff that came with Honeywell's humidifier?

I'll attach pictures of what I got.

Circuit board diagram

Circuit board.

Yes it is possible to install the humidifier without the airflow switch Honeywell provides. If you are not sure how to do this, then the safest thing for you to do is call a professional to help you with this, on-site. Electrical circuits are nothing to mess around with if you are not familiar with them. Sorry, but I do not feel comfortable giving any specific wiring instructions here and therefore will not. It would be unwise and irresponsible for me to do so in an open forum that can be read by all people of varying backgrounds and competency levels. Best of luck to you in getting this installed.

This post was edited by ryanhughes on Sat, Nov 30, 13 at 21:12

I understand where you come from but this is why there are forums for DIY'ers I'm not incapable of installing this its just not my profession. Would you tell me if I wanted the humidifier to be on with just heat would I install the solenoid to W on the circuit board and then the other wire from the solenoid to the humidistat and from the other wire on the humidistat to G on the circuit board.