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Discussion Starter · #1 ·
The central AC in my 480 sqft shop/office went caput. The air handler is in the attic. The building has two 240sq ft rooms. I have been advised to go with either a mini split system, or just cut a hole in the walls of both rooms and install 2 window units. I'm not really too keen on the latter idea. What if I installed a 2-ton mini split unit in the back office wall, then used the existing air handler ,which still works (in the attic), to circulate air through the rest of the
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I would look at a mini split system with one condenser and 2 head units, one in each room.
 

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I have to ask.....whats a "weeding table"?
Two mini splits using one condenser may give you the best results.
And you can always run just the fan on your air handler, maybe slow it down a bit if you need the circulation.
 
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What's wrong with existing unit?
If the problem is electrical, fix it.

If it's leaking refrigerant - fix could be worth it if it's not too old and running 410a instead of 22.

You can buy ducted mini-split air handler, granted to runs have to be short/low pressure drop to make it work.

or just go for a 1.5 ton central and have the blower speed set as low as it can safely go without freezing the indoor coil - to cut capacity.
 

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Discussion Starter · #8 ·
I have to ask.....whats a "weeding table"?
Two mini splits using one condenser may give you the best results.
And you can always run just the fan on your air handler, maybe slow it down a bit if you need the circulation.
Thanks!
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Discussion Starter · #9 · (Edited)
What's wrong with existing unit?
If the problem is electrical, fix it.

If it's leaking refrigerant - fix could be worth it if it's not too old and running 410a instead of 22.

You can buy ducted mini-split air handler, granted to runs have to be short/low pressure drop to make it work.

or just go for a 1.5 ton central and have the blower speed set as low as it can safely go without freezing the indoor coil - to cut capacity.
Thanks. The unit was installed in 1999, so the refrigerant is obsolete.. Likely in the leak is in the air handler which is in the small attic space, and would be difficult to get to..
 

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R-22 isn’t obsolete. It’s easily obtainable.
But some companies price it to push new equipment.
It usually spikes in cost right about this time of year as well.
There are also R-22 drop in replacements that can be used.
Older R-22 equipment shouldn't have a lot of money invested however.
R-22 isn't cheap though to begin with.

There are also the drop-ins with capacity loss.

1999 system not worth fixing leak on.
 

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There are a few inherent problems with R-22.
Any equipment that uses it is probably running on borrowed time.
Older equipment has simple analog technology rather than digital. That may limit it's ability to be flexible and keep it less efficient.
And of course newer equipment will have a higher SEER rating saving money right from day one.
And R-22 is available....but it can easily cost twice the newer refrigerants. And old units do spring leaks.
 

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I have mini splits. They are complicated equipment compared to traditional ac. As you know they have chips, electronics similar to cars. I have found no one that can fix them. The service people say replace it when it breaks. I installed one and about 9 months later it broke. I called installer and he said it needed $500 board. I thought "wait". I called manufacturer and figured out maybe fuse had blown. I fixed it myself for 50 cent fuse. I would not install another mini split.
I would recommend to install 2 units not 1 unit with double head. This way if one unit breaks you can still work in your business because the other unit wIll still be working.
In fact, maybe just start with one unit in the production area and see if that will make the entire area good. In my case, I have unit in bedroom and it keeps large bath same temp. But in your case you have garage door which is probably not well insulated so you probably need more ac than I do.
You might consider window unit. I have heat pump LG LW8016HR for cooling and heating. Costs around $600 and is quiet. (HD has this unit in their stores.)
Maybe you could put that in showroom because I assume it is occupied less frequently therefore might merit less cost system.
 

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Discussion Starter · #14 ·
I have mini splits. They are complicated equipment compared to traditional ac. As you know they have chips, electronics similar to cars. I have found no one that can fix them. The service people say replace it when it breaks. I installed one and about 9 months later it broke. I called installer and he said it needed $500 board. I thought "wait". I called manufacturer and figured out maybe fuse had blown. I fixed it myself for 50 cent fuse. I would not install another mini split.
I would recommend to install 2 units not 1 unit with double head. This way if one unit breaks you can still work in your business because the other unit wIll still be working.
In fact, maybe just start with one unit in the production area and see if that will make the entire area good. In my case, I have unit in bedroom and it keeps large bath same temp. But in your case you have garage door which is probably not well insulated so you probably need more ac than I do.
You might consider window unit. I have heat pump LG LW8016HR for cooling and heating. Costs around $600 and is quiet. (HD has this unit in their stores.)
Maybe you could put that in showroom because I assume it is occupied less frequently therefore might merit less cost system.
I ended up buying two 1 ton mini splits. So far, I have only installed one of them because I have other more pressing issues to deal with. Right now it is 99 degrees outside, 33% humidity, and it is very nice and cool in the building. I have the one unit installed on the back wall of the room with the garage door and the old air handler is helping to circulate it through the whole building. I'm very impressed with it so far.
 

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Beware of cheap off-brand mini-splits, which may seem good until they break and you can't get parts/support easily.

For primary heating in a cold climate or cooling in a very hot climate, I would go for a common make like daikin, mitsubishi, fujitsu.
 
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