Vertical gas unit installed horizontally

:shock: On an inspection today, I discovered a new vertical gas central heat unit installed horizontally. The owner/seller was told by the contractor that this is ok. I disagree, as I can see all sorts of efficiency and safety issues. Is there any exception that allows this? The burners are, of course, now vertical, so any CO2 or CO will never even have a chance to exhaust properly. I know this ain’t kosher, but would appreciate comments on how you would write this up. Website links addressing this issue would also be appreciated.

I’ve been finding new “vertical” units installed horizontally and upside down. Fortunately, the manufacturers’ installation guides have also been available, and they have specifically stated, and shown pictures, of their units being installed vertically, horizontally, and upside down. So don’t rush to a judgment; however, if you are unsure, recommend further evaluation by a licensed heating and cooling professional based on “non-standard” installation. It’s worked for me.

Yes, they can do either way now.

Things don’t just flow upwards these days. The draft is induced and gets discharged no matter how it is installed.

Got any pic’s to post?

Here’s a picture.

Inspecting the furnace is usually one of the last things that I do at an inspection. About halfway through the inspection, my Client came to me to ask me about the upside down furnace. I had no idea what she was talking about, so she showed me. I told her I had never seen one installed upside down because most people can see that the labels are difficult to read, so that’s kind of a bop on the head that something might not be standard.

As I looked at it, I found the manufacturer’s installation guide and quickly went through it. There in the guide, about halfway through, were illustrations of the unit installed vertically, horizontally, and upside down. Everything I saw indicated that it was installed properly.

I still told my Client that since it had been installed four years ago and, in line with what we do (or don’t do, as the case may be) here in San Diego, it probably had not been inspected since then. I told her that gas-fired appliances should be inspected annually; that there are areas inside the furnace that need to be looked at; that there could be problems that I can’t see, that can only be seen by taking apart sections of the furnace; and that only licensed heating and cooling specialists should be taking apart the furnace. I also told her that because of that, it needed to be thoroughly inspected by a licensed heating and cooling professional before the heating season came to ensure that it was operating properly and not spewing carbon monoxide into the house.

Moral of the story, I guess, is that when something “looks wrong,” even when it is right, don’t leave your Client to find it and wonder about it months down the road. Point it out to them now.

01 heat fau 2.jpg

Double R…
I always appreciate your message of ‘over delivery’ to our clients.

Like any relationship, poor, incomplete or just a lack of communication creates (or can create) a great deal of issues.

Thanks for the post Jimmy!

:slight_smile: Thanks, fellas. I checked with a couple of reputable local guys, and they both assured me that if the installation was done properly, etc…blah, blah…

I suppose that small amount of combustion gas that escapes into the attic BEFORE draft is induced is insignificant. The installation itself is tight, level, and proper in every way. But, as always, my first policy is CMA, especially on issues wherein clients may wake up dead. I’m still not convinced this furnace will heat as efficiently installed this way.

I had a furnace installed, and per the instructions it could be installed vert and hort. It appears a tip off is the drain lines, they should always be connected at points to prevent pooling in the exhaust line(s).


The draft induced fan will come on and run for a short duration before the valve is opened and gas begins to flow. You can hear all of it if you are near the unit with the cover door off. The fan comes on and begins to run as soon as heat is called for at the thermostat, After a short time you can actually hear the click when the gas valve is opened, then if it has a hot surface ignitor that will slowly turn red hot or if it is an electronic you will hear the spark ignitor begin to fire. So in short there is really no escaping of CO into the home unless there is something wrong witht the system. All during this time the draft induction fan is still running and will continue to run. The circulating fan will come on eventually and start circulating the warm air thru the ductwork. Good system and very safe.

ok, but why would it have to be installed upside down? so that the piping is on the side the contractor wanted it on??

Two reasons:

1 - A vertical furnace around here is less expensive than a horizontal furnace.

2 - To take advantage of air ducts already in place from a previous system, i.e., the air ducts are in the crawl space.

There are very few dedicated horizontal furnaces being made. Most are multipoise and can be installed upflow, downflow or horizontal. The Lennox G51 can be installed upflow, downflow, horizontal left or right. Other manufacturers such as Trane may specify that their upflow can also be installed horizontal left; their downflows can also be installed horizontal right.

My feable attempt tp get rid of canadian BS

Update: I was not entirely convinced by the locals about this particular furnace. Even though draft is indeed induced, the unit was installed “on its back” so to speak. I checked with a Carrier rep, and he faxed me the installation instructions for the unit which specifically states that the units are NOT to be installed either on their backs, or on its belly…here’s what it says, had the installer taken the time to read it (assuming he CAN read):


“DO NOT install the furnace on its back or facing down. Safety control operation will be adversely affected. Never connect return air ducts to the back of furnace. Failure to follow this warning could result in fire, personal injury, or death.”

Glad I waited a few hours before delivering that report!

Thanks again, fellas, for your input, and remember…if it ain’t laying on one side or the other, be suspicious!

“Hmmmm…this’n smells worse than a hog waller full of lawyers.”

My feable attempt tp get rid of canadian BS

A furnaces efficiency is not based on the position it is placed in. It dose not know that it in the up flow or horizontal position it just burns gas and moves air.

Hmm. Just like Uncle Lester.