Deck Minimum Clearance Over A/c Compressor

CliffHollen

Hello all,

I have been referencing your forum for months but this is the first time I have had a question I couldn't find the answer to and I'm hoping one of you can help.

I am bidding on a small deck in Ohio that will be over an existing a/c compressor. The deck is a little outside of my norm, but it's part of a bigger kitchen project. I need to know how much clearance I need above the compressor? The electrical disconnect will be under the deck on the far side of the compressor, but I don't think that will be a problem?

Thank you very much for your help,

Cliff

NickTech

if moving the unit is not an option, then the minimum clearane for the topside discharge will be stipulated in the installation manual. if it's not around then google the model number

SelfContract

Its discharge outlet/fucntion should be in open air and free of any type of blockage... Otherwise, the hot fan-air circulation will be blocked or limited, causing it either over-heat, over-worked, and the life span of compressor will be shortened or whole broken down soon, etc.

CliffHollen

Well, it definitely won't be "blocked". There is no other reasonable place to put the a/c. It's in a 5'x6' "nook" that is cut out of the corner of the house. There will be about 18" of clearance between the top of the a/c and the joists and it sits out about 2' from both sides of the house. The deck will still be open underneath with the exception of open stairs on one end, so the only thing really changing is the slotted deck ~24" above the fan. At least it will be in the shade!

bwalley

Not enough clearance, selfcontract gave you the proper information.

The unit will run high head pressure, also you have to have unobstructed access to the disconnect.

Covering the condensing unit will shorten the life span of the unit and make it hard to service and replace.

BigMikeB

I don't think any manufacturer will say less than 4' of clearance over the top of the condensing unit. You really need to move it. Or be prepared for the lawsuit and replacing the condenser the first week of hot weather.

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neolitic

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CliffHollen

Okay. This is one of those situations where plan A sucks, there is no good plan B and the homeowner is not going to be happy without the new door/deck/stairs. Thanks for the advice everyone! Back to the drawing board.

NickTech

think outside the box!
how bout setting the unit on the roof, or getting a contractor to find a side discharge unit. i don't suspect water cooled is an option. is there well water? a good ol' school tech will fiqure something out. some of the newer guys (no offense) are slave to manufacters and their products, keeping them inside the "box". you are limited to your imagination (local codes and $$ too)

CliffHollen

Thanks, Nicktech. I like where your head's at. I sort of just had the same conversation with myself on my way home. No well water. The condenser is 21 years old, so replacing it with something that would work is not a bad option. It's a pitched roof on a two story in an old yuppie community with strict ordinances so I doubt roof mounting is an option. You're right, old school or otherwise, i need a resourceful HVAC guy. I have never contracted with HVAC at all, so I don't know who to start with there yet.

I considered some sort of exhaust fan under the deck that would kick on with the compressor and blow air out from under the deck. Ever seen anything like that done? In theory, it seems like a functional, affordable, practical option.

DCHVAC

I ran into this problem once when a GC put a deck over TWO of my condensers. The homeowner didn't want the units moved and there was only 18 inches of clearance to the joists. We ended up cutting holes in the deck and installing ridgid floor grilles directly over the condensers. Depending on your deck layout, this may be an option for you.

CliffHollen

DCHVAC, that's definitely an option. So far so good with that setup?

bwalley

What is going to happen when the client has to install a new condensing unit and it ends up being too tall to go where it currently is?

flashheatingand

That's a terrible option. I understand having to do what you have to do, but the appliance should not be placed under the deck. Why? One, the performance issue is definnately a reason, as is the warm air coming through the floor, but also, the noise. Most people will find the noise coming from the appliance objectionable. Especially while entertaining. Another reason why I wouldn't recommend under the deck is because it will likely trap the dust/dirt from down below on the coil.

Couldn't you dig a trench for the electric & line-set and re-locate the unit on a "remote" somewhere more favorable location? If I were in your situation, I would find out what exactly are the zoning requirements/ restrictions.

Down below is the worst option. It would be better to install the unit on the deck as opposed to down below. This is just "food for thought". Good luck.

DCHVAC

Two seasons and no issues with the equipment. The reason the homeowner wanted it that way is because the deck was large, 25x40, and the equipment was at the far end away from activity.

DCHVAC

I would never bury a lineset. When underground in a cooler climate, the vapor could turn back into a liquid and slug the compressor on restart.

CliffHollen

I don't think there are any good options. The a/c sits in a 5x6 nook cut out of the corner of the house. From that corner, one side of the house is the concrete patio (the whole objective is a path from the kitchen to the patio without walking all the way around the house) and the neighbors driveway is about 18" off of the other side. There is not another place to cut in the door from that side of the house. Even if you wanted to move the ac to the other side of the house, it's a corner lot, so the other two sides are the front of the house. The first floor is elevated about 40" off the ground. The proposed 6x5 deck is just a landing. It will fill the nook, span the ac and the stairs will shoot down to the patio. The ac is next to the patio as is, so the noise/air movement issues with the ac being under the deck are a non-issue. I have an HVAC guy meeting me there Monday. Obviously the grate is far from ideal, but so far it seems to be the best viable option.

Thanks for the help everyone. More brainstorming is very welcome.

NickTech

if the a/c is 21 yrs old. im sure its due for replacement very soon. perhaps the HO should consider replacing it b4 the deck is built. newer units are considerably taller and could prove a problem. could the unit be moved to the outer perimeter of the deck? shop around for a side discharge unit like a fujistsu or mitsubishi. also an a/c guy can customize the unit for side dischare if he's worth his salt.

NickTech

a lineset buried wont run the risk of recondensing your vapor. the underground temp would have to be at or below the saturated refrig temp. which is like 40 deg or lower b4 the would happen plus ya got a good 10 deg of superheat. if the line is run in a 2 or 3" pvc conduit it would be fine.

NickTech

i've worked with units that had aux. cond. coils installed remotely and with condenser air assisting fans. i actually built a unit where the comp and controls are located in a "dog house" like in a refrig application, and the condenser itself was on its side using a vertical blower/fan to draw air threw it. it was for a job i did in a crawlspace which was the only place i could put it. of course the air intake and exaust was ducted to the outside. it worked fine for the 10 yrs i services it, after which i left the co.