Stacking AC units

[Brandon Whitmore]

I inspected a row house today where there are multiple AC units stacked on top of each other. They are stacked 3 high and installed about 9" from the building. The AC units are open to the exterior on all sides otherwise. I can't find anything in their installation instructions stating whether or not it is allowed. Anyone know whether this is a proper installation?

http://www.bardhvac.com

Also, where can I find manufacturers installation instructions for the proper installation of the evaporator coil pan and drain line/ trap installations? Would I have to determine the manufacturer of the drain pan? I have been told that most manufacturers do not allow the installation of a running trap, which is what is installed on this unit.

Any help would be appreciated.

[StevenT]

Brandon,

If the AC units are stacked, is the exhaust of the lower ones being blocked? If the exhaust is blocked and the hot exhaust air is being forced down and being drawn back into the units to cool the coils, don't you think it would have an effect on the performance of the unit?

[Brandon Whitmore]

Well, that link isn't working for some reason.

Here is the data plate for the AC unit and a pic of the horizontal unit

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[Brandon Whitmore]

The exhaust air is not being blown onto the coil fins, so this is probably fine. I just can't recall ever seeing this before. The coil fins are on the side facing the wall.

[sirch]

They look like heat pumps that I call mini-splits,but maybe the photo is making them look smaller than they actually are.Most mini-splits that i see are designed for small areas.

[StevenT]

Hi Brandon,

I've seen these minisplits stacked on multiple occaisions, although usually on some type of rack or bracket system.

I would call the mfg. and ask them about clearance in front. There are so units in that small space, blowback might still be an issue. I would also ask them about stacking them directly on one another.

[Brandon Whitmore]

I just spoke with their technical services guy. These units are allowed to be stacked 3 high with their stacking kit/ brackets. They only require an 8" clearance to the wall on the condensing coil fin side, so it just makes it.

It was like pulling teeth trying to get a definitive answer regarding how the condensate drain line should be plumbed. He said that they recommend a P trap and he personally does not like running traps, but could not point me to anything in writing on their website......... another grey area.

Thanks for the help guy's

[Eric B]

I wonder how much of the exhausted air (heated) is pulled right back into those units. I gotta think it's not what the manufacturer had in mind.

[Billy_Bob]

Those units work best if cooler air is entering the intake. It looks to me like that fence would keep the hot exhaust air in that area and it would be drawn back into the intakes.

This is like a car air conditioner on a very hot day. The air coming out in the car is not as cold as it is on a cooler day.

Basically if the hot exhaust air is recirculating, then the units may need to work longer and would use more electricity.

If the area has mild summers like in the 80's, then probably not a big deal. If somewhere like Arizona in the 120's, then I would move the fence or install a louvered fence (need all the cooling power you can get there!)

[hausdok]

Hi,

I think this whole discussion is over-thinking the situation and is going out-of-bounds.

We observe and report and we can't predict unless we know. The intial poster reviewed the units operating instructions and didn't find anything to prohibit it; then he checked with the manufacturer and confirmed that it's within the manufacturer's parameters. That's all that's necessary to report to the client.

We aren't hired to be HVAC designers and engineers and provide the client a list of what-if's or unproven theories based on unrelated data. If we don't have a deficiency and the item is installed to manufacturer's specifications and there aren't any safety issues involved, we need to move onto the next item.

ONE TEAM - ONE FIGHT!!!

Mike

[Eric B]

Sorry Mike,

My experience got the better of me.