confused about mini-split charging port thread size

[uniwelder]

I'm about to install a mini split at my house.  This will be my third one, but the other two I did 95% and then had an hvac guy do the vacuuming of the lines.  He charged $300 for the service each time and he's currently booked out for the new few months.  I'd like to do it 100% this time, considering I think I'll be doing a couple more in the next few years.  I could ask the guy I know, and he might be understanding since he doesn't have the time to work on it, but I feel like I should try doing it completely on my own if I'm not going to hire him.  @index had a great post recently about procedure and tools. 

There is a detail I'm really stuck on, which is the charging port size.  All refrigeration adapters say they're for 1/4" or 5/16" threads.  However, my unit is a Fujitsu and the threads on the charging port measure 1/2"-20.  I can't find any adapters or mention of that size, except the Fujitsu manual that says it is to prevent refrigerants other than R410A from being used.  The only adapter I see that mentions 1/2-20 is this--- https://www.amazon.com/Uniweld-EZABM90-Ez-Turn®-Anti-Blowback-Adapter/dp/B01IFQVF54/ref=sr_1_1?crid=M3KNM1DU0REO&keywords=r410a+1%2F2-20+adapter&qid=1660520199&sprefix=r410a+1%2F2-20+adapter%2Caps%2C67&sr=8-1
but the 1/2-20 is in parenthesis next to the 5/16".  Are 5/16" charging ports actually 1/2-20 when measured?  I'm having trouble finding info about this.

Also, does anyone have tools and are interested in selling?  vacuum pump, adapters, vacuum gauge, etc?

[derekjr]

You need this adapter.  It will fit on the end of refrigerant hoses and be the correct size for a Fujitsu port.  It is not low loss, so you'll need to remove it quickly or lose a bunch of refrigerant and freeze your hand.

[uniwelder]

You need this adapter.  It will fit on the end of refrigerant hoses and be the correct size for a Fujitsu port.  It is not low loss, so you'll need to remove it quickly or lose a bunch of refrigerant and freeze your hand.

So you’re saying that a 5/16” port is actually 1/2”-20?  I don’t need the exact adapter you linked to, just any 5/16” adapter should do it?

[BudgetSlasher]

You need this adapter.  It will fit on the end of refrigerant hoses and be the correct size for a Fujitsu port.  It is not low loss, so you'll need to remove it quickly or lose a bunch of refrigerant and freeze your hand.

It would be better to purchase a shutoff to go between the hose and the adapter rather than doing the quick removal. It has the added benefit of being the legal way as well.

I believe low loss is only for losses from the hoses so you'll still need to remove the fitting quickly to reseat the valves in the exterior unit ... unless you are pulling and replacing the valve cores.

I haven't done Fujitsu but I would recommend getting a valve core puller for the exterior unit. It makes pulling a vacuum quicker and eliminate the risk of losses of vacuum/refrigerant and freezing while disconnecting hoses as the valve is either present and seated or removed and the system is sealed off.

[uniwelder]

You need this adapter.  It will fit on the end of refrigerant hoses and be the correct size for a Fujitsu port.  It is not low loss, so you'll need to remove it quickly or lose a bunch of refrigerant and freeze your hand.

It would be better to purchase a shutoff to go between the hose and the adapter rather than doing the quick removal. It has the added benefit of being the legal way as well.

I believe low loss is only for losses from the hoses so you'll still need to remove the fitting quickly to reseat the valves in the exterior unit ... unless you are pulling and replacing the valve cores.

I haven't done Fujitsu but I would recommend getting a valve core puller for the exterior unit. It makes pulling a vacuum quicker and eliminate the risk of losses of vacuum/refrigerant and freezing while disconnecting hoses as the valve is either present and seated or removed and the system is sealed off.

I checked my other unit (LG brand) to see if its the same thread or different, and its also the same 1/2"-20 at the charging port.  I'm really just looking to know at this point whether 1/2"-20 is the standard size that mini-splits use.  Do you happen to have any of these valves or adapters laying around that you could measure to see? 

As a bonus, I'd love to know why its called 5/16" when that seems to have nothing to do with reality.

[derekjr]

You need the adapter I linked or any other with the same measurements (5/16 female, 1/4 male).  Mitsubishi uses ports that gauge set hoses fit onto (1/4 female, 1/4 male).  Every other mini split that I've seen needs an adapter.  Fujitsu definitely does.

A shut off between the adapter and your gauge set isn't going to prevent you from needing to take the adapter off while the shrader valve is depressed and the lineset under pressure.  So do it quickly.

You can do it with no release with a shrader tool like BudgetSlasher said.  Make sure you get one that is dual sized (5/16 female & 1/4 male), so it can fit directly onto the minisplit.  But to accomplish this, you'll be more likely to let some air in the system as you need to re-install the shrader core while lineset is under vacuum.  Removing the adapter is a de minimis release and legal (but if we are talking about legality, someone without an EPA cert installing a mini split is likely not legal)

[BudgetSlasher]

You need this adapter.  It will fit on the end of refrigerant hoses and be the correct size for a Fujitsu port.  It is not low loss, so you'll need to remove it quickly or lose a bunch of refrigerant and freeze your hand.

It would be better to purchase a shutoff to go between the hose and the adapter rather than doing the quick removal. It has the added benefit of being the legal way as well.

I believe low loss is only for losses from the hoses so you'll still need to remove the fitting quickly to reseat the valves in the exterior unit ... unless you are pulling and replacing the valve cores.

I haven't done Fujitsu but I would recommend getting a valve core puller for the exterior unit. It makes pulling a vacuum quicker and eliminate the risk of losses of vacuum/refrigerant and freezing while disconnecting hoses as the valve is either present and seated or removed and the system is sealed off.

I checked my other unit (LG brand) to see if its the same thread or different, and its also the same 1/2"-20 at the charging port.  I'm really just looking to know at this point whether 1/2"-20 is the standard size that mini-splits use.  Do you happen to have any of these valves or adapters laying around that you could measure to see? 

As a bonus, I'd love to know why its called 5/16" when that seems to have nothing to do with reality.

I do have some adapters for b/t the vacuum hoses and and LG 36k unit in a trunk somewhere stashed away in the workshop. According to my email records they are 5/16 SAE female to 1/4 SAE male, unfortunately for measuring I am away from home and probably will have forgotten about this by the time I get home.

[uniwelder]

You need this adapter.  It will fit on the end of refrigerant hoses and be the correct size for a Fujitsu port.  It is not low loss, so you'll need to remove it quickly or lose a bunch of refrigerant and freeze your hand.

It would be better to purchase a shutoff to go between the hose and the adapter rather than doing the quick removal. It has the added benefit of being the legal way as well.

I believe low loss is only for losses from the hoses so you'll still need to remove the fitting quickly to reseat the valves in the exterior unit ... unless you are pulling and replacing the valve cores.

I haven't done Fujitsu but I would recommend getting a valve core puller for the exterior unit. It makes pulling a vacuum quicker and eliminate the risk of losses of vacuum/refrigerant and freezing while disconnecting hoses as the valve is either present and seated or removed and the system is sealed off.

I checked my other unit (LG brand) to see if its the same thread or different, and its also the same 1/2"-20 at the charging port.  I'm really just looking to know at this point whether 1/2"-20 is the standard size that mini-splits use.  Do you happen to have any of these valves or adapters laying around that you could measure to see? 

As a bonus, I'd love to know why its called 5/16" when that seems to have nothing to do with reality.

I do have some adapters for b/t the vacuum hoses and and LG 36k unit in a trunk somewhere stashed away in the workshop. According to my email records they are 5/16 SAE female to 1/4 SAE male, unfortunately for measuring I am away from home and probably will have forgotten about this by the time I get home.

Thank you.  This gives a bit more assurance that I just need the common 5/16" components. 

I'd still love to know why its called that.  Does speaking in code give more job security?  Like a secret handshake.  DIY customer looks for something to fit a 1/2" thread, and the guy behind the counter knows he's not a professional because he's 'not in the know' that he should be asking for a 5/16" fitting instead?

[index]

This is the part you need:

https://www.amazon.com/Appion-MGAVCR-Vacuum-Rated-Removal/dp/B0B2MP63CW

Remove the valve core. It's not hard. Break the vacuum by releasing 410A from the outdoor unit then reinstall the valve core.

Here is a quick chart of tube OD to thread size:

https://www.anplumbing.com/an_thread

[uniwelder]

This is the part you need:

https://www.amazon.com/Appion-MGAVCR-Vacuum-Rated-Removal/dp/B0B2MP63CW

Remove the valve core. It's not hard. Break the vacuum by releasing 410A from the outdoor unit then reinstall the valve core.

Here is a quick chart of tube OD to thread size:

https://www.anplumbing.com/an_thread

That tube OD to thread size makes the most sense.  I don't have a tube size to compare against, but at least I know there is some rational. 

Index--- I had sent a private message before creating this thread, but I guess you haven't seen it.  Your explanation on a previous thread, with the list of items to buy and the youtube video link, was very helpful. 

[uniwelder]

Update— The vacuum pump components have all arrived. In total I spent about $450.  I don’t have the mini split hooked yet, but I did try the pump on its own. With just the gauge hooked to the pump, I can get to 4 microns. When I hook up the hose and fittings to the gauge, it only pulls to 240 microns. I’m afraid of crushing the o-rings if I tighten more, but I don’t know if that’s really a valid concern. It sounds like 240 is good enough anyway.

I bought the pump from Harbor Freight, $150, 2 stage unit. Ordered from Amazon were the CPS brand gauge, Appion core removal tool with 5/16” fitting, Yellow Jacket 1/4” hose, Yellow Jacket vacuum rated 1/4” valve, and blue Nylog. As everyone has been saying, the 5/16” fitting does indeed have a 1/2”-20 thread that matches the charging port of my mini split.

[index]

As long as you can get the system down to that range you will be fine. My vacuum pump pulls down to 50 or 60 microns at the gauge when on but i get a quick decay to the low 200s where is holds. I only hand tighten the connections.  Did you burp the ball valves on your core removal tool and valve?

[uniwelder]

As long as you can get the system down to that range you will be fine. My vacuum pump pulls down to 50 or 60 microns at the gauge when on but i get a quick decay to the low 200s where is holds. I only hand tighten the connections.  Did you burp the ball valves on your core removal tool and valve?

When I’m testing it, I haven’t had it hooked up to the mini split, my arrangement has been vacuum pump to hose to tee connector to closed ball valve with gauge coming off the tee. That allowed everything to match up male-female with a closed end. Connections are hand tight.

[uniwelder]

You need the adapter I linked or any other with the same measurements (5/16 female, 1/4 male).  Mitsubishi uses ports that gauge set hoses fit onto (1/4 female, 1/4 male).  Every other mini split that I've seen needs an adapter.  Fujitsu definitely does.

OP here with an update.  After successfully installing my Fujitsu mini-split about 6 weeks ago, I went to help a friend yesterday install the copper lines on his Mitsubishi unit.  I hadn't referred back here beforehand, and confidently brought all my tools, but was disappointed to find the 5/16" core removal tool wouldn't thread on.  After coming back to here to complain, I read through the responses again and came across the one quoted above.  Mitsubishi uses 1/4"--- yes, yes indeed they do.  He's buying a 1/4" core removal tool and we're going to try again this weekend.