DIY mini-split kit or basic parts kit installation

windtrader · August 28, 2020, 01:15:05 PM

Read through many mini-split posts but did not read much about those who had to do at least some freon charging and some tubing flaring and such.

Trying to decide which way to go. The MRCOOL DIY kits come fully charged and tubing dressed and ready to connect, cost is higher naturally than other brands where compressor is recharged but line is not so install required vacuum and some freon charging.

Not having proper tools nor previous AC install experience, on the fence about paying up for MRCOOL DIY kit. Several hundred dollar premium making me mull it over.

someguy · August 28, 2020, 05:19:56 PM

I've been thinking about building a system from scratch too.

I was thinking about moving the stock condenser to the roof, using several evaporators and fans with individual control where needed.

AC Vacuum pumps are cheap. I have one for other work. What I don't have are the gauges or the know how.

richard5933 · August 28, 2020, 05:37:03 PM

They make condensing units specifically for bus rooftops, usually on city buses. Perhaps you can use that as a starting point as you design things.

somewhereinusa · August 28, 2020, 05:37:33 PM

I did make my own lines for one of the two I installed. Nothing really difficult but, I have automotive AC experience. You need gauges for 134 and an accurate scale plus the freon. A digital postal scale is much cheaper than the ones marketed for freon.

someguy · August 28, 2020, 05:44:21 PM

How do you know how much freon to put in a DIY system ?

Does the condenser need to be upright ?

How do you know how efficient your system will be ? Mini splits are engineered for high efficiency. (high SEER)

someguy · August 28, 2020, 05:46:46 PM

Quote from: richard5933 on August 28, 2020, 05:37:03 PM
They make condensing units specifically for bus rooftops, usually on city buses.

Thanks for sharing that. I had no idea.

These forums need a "Like" button.

richard5933 · August 28, 2020, 06:08:24 PM

Do a Google search for "rooftop bus a/c" and you'll see lots of options, from many of the companies you've heard from already like Eberspaecher and Red Dot. Some use engine compressors, some seem to be electric only.

Lots of these are used in things like mobile command centers, mobile libraries, etc. as well.

buswarrior · August 28, 2020, 07:17:52 PM

If you are going to put the condenser back on the roof...

Why not just put a traditional RV roof AC or heat pump?

The point is to get your height down...?

Good Grief, Charlie Brown...?

Round and round...

Why does my head hurt?

Happy coaching!
Buswarrior

bronson · August 28, 2020, 07:19:39 PM

Nothing ventured nothing gained. You can make a vacuum pump from an old fridge compressor. A set of gauges and scales not too expensive. You could probably calculate volume for hoses etc and calculate capacity but could also fill the system and watch the gauges to get you in the ball park without a scale If there's a site glass on the drier you can watch for bubbles which is an indication of low charge. Also need to learn how to solder copper.

Once I was too poor to buy a marine AC for a boat so I took a window unit and cut off the condenser and mounted it in a tank .
The tank was mounted under sink in the head. Ran copper lines from it to AC and installed a livewell pump to constantly exchange water in tank. Worked great.

chessie4905 · August 28, 2020, 07:23:59 PM

Time to purchase the coach, then get back to us.

someguy · August 28, 2020, 08:18:32 PM

Quote from: buswarrior on August 28, 2020, 07:17:52 PM
If you are going to put the condenser back on the roof...

Why not just put a traditional RV roof AC or heat pump?

Because they are crap quality and poor efficiency. And I don't want an AC poking through the ceiling in my coach. You got a problem with that ?

QuoteThe point is to get your height down...?

Who says I have a height problem ? You might be concerned about height, I am not. Did I mention anything about height ?

Why don't you worry about your coach and I'll worry about mine.

Iceni John · August 28, 2020, 08:34:19 PM

I bought a Pioneer 12K inverter minisplit with heat pump that will be a mostly-DIY installation, but I will have a professional A/C tech do what I cannot, such as pulling a vacuum in the lines for 24 hours to check for leaks. My outdoor unit is precharged with refrigerant, but the lines still need to be evacuated; they are however already dried and sealed against any further moisture getting inside before they're installed. I deliberately chose a system that doesn't have precharged lines, specifically so I could check for leaks before opening the valves to let the refrigerant into the lines.

Whether the Pioneer is any better than any other comparable brand is of little concern to me - all minisplits are of comparable overall quality and are a mature technology by now, and any warranty will be negated anyway if it's known that it's in a vehicle, so I chose one that's not too pricy but not suspiciously cheap either, and one that plenty of RVers and mobile users are having good success with. Yes, I could have bought something different with a higher SEER, but that's not my main concern with 2kW of solar on the roof!

John

windtrader · August 28, 2020, 09:41:12 PM

John,

Must not have written the OP clearly but you are spot on with my dilemma. The MRCOOL DIY kit has lines and compressor precharged so no need for gauges, bulk freon, flaring tools, etc. The Pioneer type kits do not have precharged lines and that steps takes the tools and skills to DIY or hire that out.

The MRCOOL DIY kits are premium priced for eliminating having the installer to do any AC specific work, just hook up and route tubing. I'm leaning toward the MRCOOL option as there is value but just not sure if totally worth the higher product price. Going to Youtube a few installs with the Pioneer type kit then decide.

BW - I'm very clear nothing involved with AC is going on the roof. I may be nuts but not crazy. lol

someguy · August 28, 2020, 09:45:52 PM

You mean crazy like Marathon?

windtrader · August 29, 2020, 11:35:10 AM

Update.
Originally landed on MRCOOL products and DIY 120v 12k BTU unit. This kit is the easiest to install and requires no special tools, equipment, knowledge, or skill.
More research ran me in circles, all the while, gaining more knowledge about this specialty field.
Finally, came back around to MRCOOL as it is a solid and very popular product. Rather than the DIY models, I chose the Advantage series. Order is placed via Lowe's.

MRCOOL Advantage 3rd Gen 12,000 BTU 1 Ton
Ductless Mini Split Air Conditioner and Heat Pump- 115V/60Hz 19 SEER
Item #2538961Model #A-12-HP-115B

Quick analysis.
The Advantage is far less costly than the DIY series but the performance is slightly less on paper but still very respectable capability. The added steps are quite manageable. Initially, working with the pressure fittings and such seemed a bit daunting but after a video or two, it was a cakewalk. We all here have the requisite experience as it is the same stuff we do servicing AC in our cars and the brake and steering systems - nearly same stuff.
Purchased using credit card and from Lowe's, both offering the best protections for handling all transactional and product issues.

The runner up was Pioneer, good pricing and decent reviews and same type of kit as the Advantage but buying a solid brand from big box were the determining factor.