Mini Split Refrigerant Question R32

[Just-SKO]

Hey Everyone,

After four long-ish years, my build is 98% complete. It's a 35 ft. pusher with 3K watts of solar, over 15K watt hours of battery, and two 3K watt inverters. One of the last things to install is the mini split. I was hoping to delay the installation for a bit, but it was just too damn hot on our first shakedown trip. Everything worked great though!

So I'm here hoping to get advice from some HVAC pros for my mini split installation. I have a dual zone 18K BTU system that uses R32 refrigerant.

Question 1: R32 has a safety classification of A2L - lower burn velocity and lower toxicity. What reservations do you HVAC professionals have about using this in a mobile application knowing that the refrigerant is flammable?

Question 2: If the consensus is that it is too risky/unsafe, can an A1 refrigerant and oil combination be used instead? The unit I bought is for professional installation, so nothing is pre-charged. Or should I just return it and buy something that uses non-flammable refrigerant?

Thanks in advance!

 

[s2mikon]

R32 is the better refrigerant but r410a is less flammable but is being phased out. In some sensitive installations like marine, oil and gas installations r410a is being required instead of r32. R410a is has 50% r32 and r125. Also the oil vapor is also flammable so you have to be aware of that too.

 

[Mr P]

There is a "test" on R32 on youtube. Is it true? Legitimate? I dunno. I think the long response to the video has some interesting points.

www.youtube.com/watch?v=hWRTKoKgm_k

As a tech who services/repairs auto HVAC, almost all the of the leakage of refrigerant takes place over a long time. And remember, even if there was a catastrophic high pressure failure, that high pressure (during system operation) is in the condenser, which is outside the living area and exposed (supposed to be exposed...) to high air flow volume.

In short, it would be very unlikely to even have enough of a leak to have a noticeable problem, much less a fire.

 

[La Camioneta]

The guy that installed my mini splits said they all come pre-charged. Hook up the copper lines, draw a vacuum, watch for leaks then turn the valve and it self-charges. YMMV.

 

[s2mikon]

The last 2 that I installed back in may were 12K BTU units 240v that I installed in my darkroom about 250 sq ft. Yes overkill but the way these things work it's okay. Right now it is 105 outside and 70 inside. The units are not even running hard. These were R32 and came precharged. I think that R32 is the way to go for now.

 

[Just-SKO]

Thanks for the information everyone. I'm going to move forward with the installation.

The guy that installed my mini splits said they all come pre-charged. Hook up the copper lines, draw a vacuum, watch for leaks then turn the valve and it self-charges. YMMV.

These were R32 and came precharged.

Looked over the installation instructions and mine came pre-charged as well.

 

[s2mikon]

Use these on the flare ends. Amazon.com and some of this. Amazon.com and make sure it is leak checked with nitrogen and vacuumed well. If it leaks out you will have a hard time buying more freon if you are not in the business.

 

[Mr P]

I only do some automotive HVAC, and have never heard of a flare seal. Looks like a failure point to me. And where does the sealant go?

 

[s2mikon]

I know, they look hokey, but they were recommended by a professional HVAC guy here in town that has installed a ton of these mini splits in oilfield installations and homes. He said that the copper lines that come with these Chinese units is crummy and the copper tubing you buy now here in the states is all Chinese junk. He has tried to re-flare them and it helps but these have worked the best. Make sure that they snap in securely with sealer on both sides and torque them down. Put nitrogen in at 300-350 psi and check for leaks with soap and water and if good evacuate and open the valves and enjoy cold air.

 

[Mr P]

Interesting. I'm noting this for later consideration.

 

[Bjorkinman]

I lost my charge on the rear split I did due to a bad flare. Was 410a; I thought I would have to get an HVAC person to help but found a site icecold.us that sells refrigerant as long as you agree that "a licensed HVAC professional" will be doing the install, they shipped super quick. I really second the nitrogen purge too, I'm lucky enough to work somewhere with access to nitrogen and was able to do a pressure test before charging and two months later its still cold.

 

[jbeech]

s2mikon said in part . . . If it leaks out you will have a hard time buying more freon if you are not in the business.

And he's giving you the money shot because while you can buy it today if you pinkey swear a pro will be involved, the question really revolves around, can you buy some in 5-10 years without breaking open the piggy bank? Or will it be cheaper to rip out and install a replacement system?

Meanwhile, and by way of example, right now the HVAC at home has a slow leak. Uses 410A and that stuff is expensive ($100/lb).

Anyway, I just bought two 5T inverter systems (actually in the installation planning process) and here's what I know. I can invest in a 25lb tank of 410A right now for about $250. And while it's $500 for a 20lb tank of R32, a cylinder of R454B (the next new thing) is $900 for a 20lb cylinder.

Anyway, I've not yet spent for the minisplit for the truck but for sure it'd be plenty happy with R32 - but - I'd probably invest in a cylinder to stash for later, now, rather than pony up whatever the price is when it becomes unobtanium in 5 years.

Source? Me who with 1969 Rolls Royce and 72 350SL is always on the lookout for R12 and pays through the nose when a can pops up. And FWIW, a 30lb cylinder is $3500 . . . no, not kidding.

Note regarding R454B, yes it's even more flammable than R410A.

 

[Just-SKO]

Offering an update on this installation: I used the nylog gasket sealant and flare seal fittings for each connection. The lines that came with the unit were too short, so I orders two sets from Vevor. The flairs on all the sets were centered and smooth, much better than what I managed, but they work. We're 700 miles down the road and everything is working great. Thanks for the help everyone.

 

[Ozbozz57]

s2mikon said in part . . . If it leaks out you will have a hard time buying more freon if you are not in the business.

And he's giving you the money shot because while you can buy it today if you pinkey swear a pro will be involved, the question really revolves around, can you buy some in 5-10 years without breaking open the piggy bank? Or will it be cheaper to rip out and install a replacement system?

Meanwhile, and by way of example, right now the HVAC at home has a slow leak. Uses 410A and that stuff is expensive ($100/lb).

Anyway, I just bought two 5T inverter systems (actually in the installation planning process) and here's what I know. I can invest in a 25lb tank of 410A right now for about $250. And while it's $500 for a 20lb tank of R32, a cylinder of R454B (the next new thing) is $900 for a 20lb cylinder.

Anyway, I've not yet spent for the minisplit for the truck but for sure it'd be plenty happy with R32 - but - I'd probably invest in a cylinder to stash for later, now, rather than pony up whatever the price is when it becomes unobtanium in 5 years.

Source? Me who with 1969 Rolls Royce and 72 350SL is always on the lookout for R12 and pays through the nose when a can pops up. And FWIW, a 30lb cylinder is $3500 . . . no, not kidding.

Note regarding R454B, yes it's even more flammable than R410A.

Whoa, I had no idea. I have about half a 30 lb jug of R12 from my days as an appliance repairman. And a nearly full jug of R134A.

 

[nikitis]

I feel like they change refrigerant every 10 years to force you having to upgrade your units. It's old, not working, the unsuspecting home owner doesn't understand and is told your unit doesn't take "RX" type refrigerant which is now rare or difficult to get so you'll decide to buy a new unit.

This is planned obsolescence and it should be made illegal because it's a wasteful practice for the environment when you have to mine for minerals to make the new unit when you could keep using the existing one when all your unit really needs is a recharge with refrigerant A. They always seem to have refrigerant A but it now costs 4x as much, but it's always obtainable.

One can argue you're creating jobs, but there's so much of this going on, the economy has gotten to a point no one can afford anything anymore because this planned obsolescence strategy is applied to every other industry now.

 

[jbeech]

Wish I had that R12!

 

[Rock-N-Ruth]

Just an interesting fact: R-410A can be had for free, if you have a storage tank and a recovery machine. If you are handy you can build one with an old 10K air conditioner. Many air conditioners and refrigerators that folks don't want anymore are a source of refrigerant and other cool parts.

The refrigerant doesn't go bad. Just make sure you have a good dryer and filter system in your recovery machine.

Last year I recovered the refrigerant from a friend's HVAC system and hauled of the condenser and evaporator for him, because he was getting a new unit. The HVAC company was going to charge him $$ to evacuate and haul off the old unit. I got 26lbs of 410A for my trouble.

Word got out and other folks have asked me to do the same for them. I've had to start turning them down because I don't have any more storage available.

If you do it, you want to purge the lines before you start the recovery to minimize any air or moisture you would get in your tank.