AC on floor

[will5443]

I came across new construction Tuesday (built in 2005 - went bankrupt, and now someone else owns it and they are starting to sell off units) where the heat pump unit in the closet was sitting on the floor. There are other issues (like insufficient return air) but my main question is - can this unit sit on the ground. I do have pictures, buy my mind is not working right and I cannot seem to upload them. Thanks for your help.

[Jerry Peck - Codeman]

Can the air handler/furnace/forced air unit set on the floor?

That depends on several things, first would be a no if the return air opening is facing down, unless there is a return air duct in the floor.

It also depends on if the manufacturer's installation instructions allow for 0 inches clearance under the unit, if your local code requires an auxiliary drain pan underneath the air handler or allows for alternatives, etc. If an auxiliary drain pan is required and the unit is bottom return air/supply air, then the pan would restrict the air flow and the unit would need to be on a stand within the auxiliary pan.

One thing to consider for setting on the floor is the clearance to combustible material electric heating elements are installed for backup emergency heat to the heat pump - being as the elements are exposed to the air flow there is the possibility that pieces from a hot element may fall through the unit down to a combustible floor, this would be more of a consideration for units which have bottom return air/supply air openings than for units which have front (or side) return air openings as the front (or side) return air units have enclosed bottoms which are typically steel.

I have seen units which physically could be set on the floor as they had front return air, however, they were on stands above water heaters so I did not check to see what, if any, bottom clearances to combustible material they required in the installation instructions.

Find an air handler unit on the floor would certainly raise some flags in my mind, as it did in yours, and I would need to find the installation instructions for most of the answers, the physical installation configuration could answer some of my other questions.

If you noted the manufacturer and the model number, I would recommend a search on the internet for the installation instructions. If the unit is not very old, the installation instructions may be available on the manufacturer's web site, and if not, finding contact information on their web site for technical questions may lead to being able to get older model installation instructions even though not available on the manufacturer's web site. Sometimes emails work, sometimes it takes phone calls.