Length of Air Conditioner copper runs?

NM_Shooter · May 02, 2012, 09:46:25 AM

I'm in the process of purchasing a conversion A/C system for my house, and am trying to figure out where to place the compressor. The air handler/ evap coil is located in the center(ish) of the house. I had initially planned on placing the compressor on the flat roof in the place of the soon-to-be removed swamp cooler, but now I am having second thoughts. If I place it at ground level, I will have to run copper approximately 40'. Roughly 35' will be exposed to the outside.

Any thoughts on this? If I mount the compressor on the roof (trying to avoid the noise issue) The run will only be ~8' or so.

MountainDon · May 02, 2012, 10:07:30 AM

We had ours placed on the roof where the old swamp cooler was. Built a new platform for it. We put it there mainly because ground space alongside the house was scarce. But I also didn't relish all the copper tubing that would need insulating and protecting up the side and over the roof and down, or excavate under the slab. This is one of those times a basement or at least a crawlspace would be nice.

Down side was that when we later re-roofed we had to have an A/C guy come out and disconnect, then reconnect the lines.

May 02, 2012, 10:27:13 AM

I would suggest you find some engineering text to read on the matter ... perhaps the installation guide for the system you intend to install. To my mind, long horizontal runs are costly to install but probably otherwise would perform just fine. However, it would concern me to have components spread out vertically to any great extent, because the lubricating oil must find its way around the refrigerant system .... and having things spread out vertically can't help this need.

NM_Shooter · May 02, 2012, 10:28:09 AM

What make did you go with? I am looking at Goodman's scroll compressor. I have another one on the front of my house (mounted on the roof) and it is too noisy for my liking. Luckily it is not over the top of any bedrooms. This new compressor will be.

If I mount this on the ground, I also do not want to put it "on the ground". Traditionally it is on a short concrete pad. Because of the amount of sand blowing around my neighborhood, I want to mount this up about 2' or more. Trying to figure out how to do this without it looking atrocious.

I am doing the install / conversion myself. Found some good pricing online, and will be tying this into the swamp cooler ductwork. Will hire out the copper work and the freon fill. Also thought about making a frame for the AC compressor out of unistrut. Considered mounting the compressor on shock isolator bushings on the roof too.

Too many options.

NM_Shooter · May 02, 2012, 10:36:01 AM

Quote from: JRR on May 02, 2012, 10:27:13 AM
I would suggest you find some engineering text to read on the matter ... perhaps the installation guide for the system you intend to install. To my mind, long horizontal runs are costly to install but probably otherwise would perform just fine. However, it would concern me to have components spread out vertically to any great extent, because the lubricating oil must find its way around the refrigerant system .... and having things spread out vertically can't help this need.

Hmmmmm......
My first house was a two story house, and both air handlers were in the attic while the compressors were on the ground. Wouldn't the best system be with the compressor lower than the air handler? I can see the compressor needing the oil, but I can't imagine that the evaporator needs it at all.

My gut feel is to mount this on the roof, but I hate having to make a penetration to tie into the roof. I also hate having to rent a crane $:-\$

May 02, 2012, 11:34:35 AM

Many people have their furnaces/air handlers in their basement, with the A/C compressor being at ground level above them, so you shouldn't have an issue that way.

MountainDon · May 02, 2012, 11:50:44 AM

QuoteWhat make did you go with?

Trane. Replaced the furnace at the same time. Paid to have it done.

metolent · May 02, 2012, 03:19:39 PM

Just as a reference point, I've had 2 Goodman units now. I installed the first in my primary residence in Olympia, WA about 3 years ago after ripping out the Carrier air handler (just had the a/h, not the condensor - explain that to me?) that was installed by the builder. I installed a 3.5 Ton Goodman A/H, matching condenser, lineset, the works, but tied into the existing plenums for supply and return. Great unit and pretty quiet. I had the condenser outside of my youngest son's bedroom window.

I installed the second last year at the cabin. For this one, I went with a 2-Ton Variable-speed, A/H and condenser with about a 30' line set (although I only used about 20' of it). I mounted the A/H in the crawlspace (hanging from the floor joists, so it's super quiet), and then set the condenser on the ground outside of one of the bedrooms. Super quiet - even quieter than the 3-ton at the other house. For the cabin, I did most everything myself, including all of the ductwork, except for brazing the line set connections and the initial charge on the system. Works great and is quite efficient. There are pics of my system on my build page, which I haven't updated in a long time at this point... hmm, that reminds me.

The goodman brand got a really bad reputation for a while, but I've had great luck with recent units. When I build the next place, I'll be putting in yet another one.... Btw, the prices you can find online are actually quite reasonable. I was originally going to buy mine from Ingrams, but ended up getting them through my hvac guy directly from the distributor at cost....which was on par with Ingrams. I think I looked at Alpine as well, but their pricing wasn't quite as good.

If you were in the PNW I'd point you at my hvac guy... as he works for a major hvac shop, but moonlights. You might be able to find something similar in your area - try posting something on craigslist?

Rob_O · May 02, 2012, 09:10:05 PM

Quote from: metolent on May 02, 2012, 03:19:39 PMthe prices you can find online are actually quite reasonable. I was originally going to buy mine from Ingrams, but ended up getting them through my hvac guy directly from the distributor at cost....which was on par with Ingrams.

That internet pricing isn't so great when you have to buy "warranty"parts because the local dealer won't help you. Just something to think about when price shopping

May 02, 2012, 09:36:56 PM

Warranty? We don't need no stinkin' warranty!

That is always the issue us extreme do-it-yourselfers face though, right?

The upside is that I can install for $2500 an air conditioner that would cost me $7k if I used a local contractor. Downside is that if the compressor fries or the air handler dies I am on the hook for fixing it myself.

I installed a Goodman 5T system 4 years ago, and it is going strong!