Do it yourself mini split heat / AC

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Buck Parrish

Buck Parrish

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Location
NC & IN
The sellers are advertising these NEW MINI SPLITS as do it your self. They say except the electrical. They want you to hire a licensed electrician. My understanding is the equipment and line set are already full of the gas needed.
Supposedly you screw them on. turn the valve then run the condensate line out. No filling with gas neccessary.
My question is.
Has any body here installed one of these new DIY mini splits? How'd it work out?
 
Buck Parrish said:
The sellers are advertising these NEW MINI SPLITS as do it your self. They say except the electrical. They want you to hire a licensed electrician. My understanding is the equipment and line set are already full of the gas needed.
Supposedly you screw them on. turn the valve then run the condensate line out. No filling with gas neccessary.
My question is.
Has any body here installed one of these new DIY mini splits? How'd it work out?
Click to expand...
I have heard of these. I am unclear how the line set is connected. There is perhaps some misunderstanding about "no refrigerant needed" because they all come with refrigerant that will work up to a certain line set length. I guess you could have a line set already evacuated/filled as needed, but how do you connect it to the compressor?
 
You should hire a HVAC contractor:
1. The refrigerant lines use flare fittings; this is where most of the leaks occur.
2. You need a vacuum pump to clear the refrigerant lines.
3. The condensing units come pre-charged with R410A.
4. You will need a miniature condensate pump if you install the air handler on an inside wall.
5. You will need a charging manifold to check the pressures.
6. You need extra R410A if you have longer refrigerant lines, with extra cable.
7. Use plastic covers to enclose the refrigerant and cable on outside walls.

This is a great choice ... installing a ducted system is a waste of energy.
 
A good friend of mine recently installed 5 interior mini splits with 2 exterior compressors. He hired a HVAC technician to come in and make the final line set connections. It is an impressive system. Quiet and does a great job of cooling his house. He had a quote from a HVAC company for $33K to do his house and ended up spending less than $12K to do it himself. He did his own wiring (he has the proper license).
 
mtnelect said:
You should hire a HVAC contractor:
1. The refrigerant lines use flare fittings; this is where most of the leaks occur.
2. You need a vacuum pump to clear the refrigerant lines.
3. The condensing units come pre-charged with R410A.
4. You will need a miniature condensate pump if you install the air handler on an inside wall.
5. You will need a charging manifold to check the pressures.
6. You need extra R410A if you have longer refrigerant lines, with extra cable.
7. Use plastic covers to enclose the refrigerant and cable on outside walls.

This is a great choice ... installing a ducted system is a waste of energy.
Click to expand...
Can you comment on these pre charged or pre-evacuated lines? Is that a thing?

I have installed mini splits before and just had a refrigeration company come out to evacuate the lines.
 
mtnelect said:
electrofelon said:
I have heard of these. I am unclear how the line set is connected. There is perhaps some misunderstanding about "no refrigerant needed" because they all come with refrigerant that will work up to a certain line set length. I guess you could have a line set already evacuated/filled as needed, but how do you connect it to the compressor?
Click to expand...
Click to expand...
The line set is precharged and the compressor and line set has connections with internal valves that do not open until you complete the connection. You have to use the length of line that is supplied.
 
So does the connection makeup have a way to expel the trapped air between the male and female connectors as it is tightened? Or do you just end up with a small amount of atmosphere mixed into the refrigerant system?

Cheers, Wayne
 
I have no experience with MRCOOL DIY single unit, only with Diakin multi units, which require a HVAC contractor to install.
 
The guy that sits next to me at work went and took a class so he can buy refrigerants and do his own air conditioning work. I think it cost him $90. Plus he had to buy the equipment which was a couple hundred dollars.
 
The line sets are not charged. No way they can be because they are open on the ends. The line sets use flare fittings. You have to be careful to notice whether it is standard or metric because the flare is not the same

What's charged is the condenser.

You don't need to have the lines evacuated unless you are changing from one type of free on to the other. There's really nothing in the air to contaminate anything inside the lindset. Besides, they come with caps on the ends

I've installed close to 2 dozen many splits. I used to hire my son (a certified HVAC tech) To vacuum the lines and check the pressure. Not anymore.

Easy peasy
 
James L said:
The line sets are not charged. No way they can be because they are open on the ends.
Click to expand...
With the Mr Cool system they are precharged and come in 16' and 25' lengths, which can be joined as required. They have a complex coupling mechanism that apparently involves some thread engagement, and then an internal valve, and then I stopped reading the patent (see claim 14).

DIY 4th Generation | MRCOOL

Comfort Made Simple
mrcool.com mrcool.com

MRCOOL Patents | MRCOOL

Explore the patents of MRCOOL's HVAC systems which include a brief summary. Click here to view our patents & contact us if you have any questions!
mrcool.com mrcool.com

Cheers, Wayne
 
wwhitney said:
With the Mr Cool system they are precharged and come in 16' and 25' lengths, which can be joined as required. They have a complex coupling mechanism that apparently involves some thread engagement, and then an internal valve, and then I stopped reading the patent (see claim 14).

DIY 4th Generation | MRCOOL

Comfort Made Simple
mrcool.com mrcool.com

MRCOOL Patents | MRCOOL

Explore the patents of MRCOOL's HVAC systems which include a brief summary. Click here to view our patents & contact us if you have any questions!
mrcool.com mrcool.com

Cheers, Wayne
Click to expand...
Interesting. I stand corrected.

I can see how it could work, like air hoses connectng to a tool and compressor.
 
BAck in the old days (1960s) there were split systems with precharged R22 lines. If too much air did get trapped in the lines as evidenced by loss of capacity due to non-condensibles in the system, simply (back then) dump the R22 and recharge to beer can cold was the proceedure.

I have seen folks connect normal mini=splits without a vacuum and the units ran (but not as well or efficiently) even with the air from the lines and evaporator in the system.

Surprised MrCool does not just supply units with a plug, then no sparky needed either.
 
With a lot of HVAC equipment if it is bought online, there is no warranty, that is something to consider if you eat the repair costs if decide to DIY it, reading the warranty is strongly advised. If it had a bum compressor that would hurt if were on the hook for it rather then the mfg.
 
I'm in the process of getting my EPA 608 license, and hope to do my first install this month.

I'm installing standard hardware without the prefilled lines, so I'll be able to report on that hopefully soon.

Jon
 
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