Whole House Humidifier on old furnace

6 years ago

I'mwwanting to install a whole house Humidifier but I'm concerned with the setup on my old, small furnace. My house is only 1300 sqft and the furnace works fine. There is a hole in the top return that it could fit but I'm worried that may be there for a reason (possibly for more return air). I'm not sure if that is duct work below to attach the 6" duct from the humidifier or if that is part of the furnace. Any help is greatly appreciated!

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PRO

Austin Air Companie

6 years ago

Your furnace is using return air as combustion air or combustion air as return air.

If there isn't enough combustion air, you get incomplete combustion otherwise known as CO (carbon monoxide) . Normal combustion = Carbon Dioxide (C02)... with that said it is not proper. Nearly any jurisdiction this install would not meet building code... because it's dangerous.

The return is open near where there is a potential for carbon monoxide, it gets drawn into and distributed thru the house.

Your flue pipe is not right material. This is not a condensing furnace.

It looks like water heater is electric so that lessens the risk a little, but you should spend your money fixing these problems before adding insult to injury.

How is the flue pipe (PVC) attached to this furnace...if you can take a picture to show how it's connected. Also what part of the country do you live in?

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Comments (9)

tyler_c_cox
Original Author
6 years ago
last modified: 6 years ago
Bottom of the furnace (Can the 6" duct from humidifier be ran here or are there internal parts there? Basically I don't think that is actual duct work but instead part of the furnace?):

Top of the furnace (can I mount where that giant hole is or is that hole needed for more air to be pulled in?)
mike_home
6 years ago
last modified: 6 years ago
This is an interesting installation. There are so many things going on here I don't know where to start.

Where is your filter? Is it at the main return in the house? Is the furnace located in a closet? Does the door have louvers?

Someone made cut this big hole in the return. Air is passing through the coil with no filtering. You have a return with an open flame in a confined space. This is a bad installation and potentially dangerous. I suggest call in a HVAC company to assess what you have before you add a humidifier.
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tyler_c_cox
Original Author
6 years ago
That is a great idea. And to answer some of your questions:

1) Where is the filter? The filter is in the return right before it goes into the furnace. You can see the door to it above (it has duct tape on it)

2) Is the furnace located in a closet? Yes. Along with the water heater it is in a closet in my foyer.

3) Does the door have louvers? Yes. The doors have louvers.

The air is being filtered (see answer to question one). Thank you for your feedback. I have had mulitple hvac people out in the past for other repairs to the furnace and so far no one has expressed concerns. Wouldn't hurt to get another hvac person and ask specifically though.
tyler_c_cox
Original Author
6 years ago
Well thanks for the scare! :-) I have already scheduled 3 different hvac companies to come out and have a look. I wasn't wanting to spend the money but it will be worth it to fix the concerns you have raised. I can't thank you enough for this information! I am meeting one of the hvac guys this afternoon so I'll take a picture of the flue pipe conneciton. Thank you again!
PRO
Austin Air Companie
6 years ago
When things are cold (nationwide) it's important, because furnaces are working overtime thru out the country right now. Safety First.

It's not a scare tactic, these are valid concerns.
tyler_c_cox thanked Austin Air Companie
tyler_c_cox
Original Author
6 years ago
Finally got the pictures! I live in Indiana (the past week it was -12 degrees. So far this week it's been below 30).
PRO
Austin Air Companie
6 years ago
Ok those pictures tell a lot. This furnace was probably one of the first condensing furnaces made, LOL. So your furnace is a condensing furnace. So that relieves the concerns of the flue pipe.

It still isn't a bad idea to get this furnace inspected though, that inducer motor has got a lot of fur babies on it. The return cutout definitely needs to be addressed, I would have that sealed up and if your system needs additional return air make the return so it draws air from outside this closet away from furnace area.

Code may also require you to bring in out door air to this closet for combustion air for furnace. That is the proper way to do it to ensure the furnace never goes into a mode of 'incomplete combustion' due to lack of combustion air. This is typically what results in the production of CO (carbon monoxide) as normal combustion results in CO2 (carbon dioxide)

Even if this furnace is not producing CO, but a crack in heat exchanger is found the furnace should be replaced. You should do these things before considering adding a humidifier to this system.
tyler_c_cox thanked Austin Air Companie
tyler_c_cox
Original Author
6 years ago
Once again I can't thank you enough! I have contacted 3 HVAC companies. 2 of them have showed up so far and agreed that there is probably a crack in the heat exchanger and just because of age should probably be replaced. Thanks again!