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Any idea on the rational for that? Maybe less refrigerant in the system or 'better' management of the liquid refrigerant? I've always been puzzled why they do that.

Originally Posted by mason

Correct, meters at outdoor unit, pressures read on the line were after it dropped.

Originally Posted by BBeerme

Can't remember the brand, but I had an interesting install on one of those mini splits years ago. The unit came with all of the insulation and instructions that were very clear that you had to insulate both the liquid and suction lines. Because the metering device was at the outdoor condensing unit (?). That could explain similar pressures you may have been seeing; just a thought.

Correct, meters at outdoor unit, pressures read on the line were after it dropped.

Can't remember the brand, but I had an interesting install on one of those mini splits years ago. The unit came with all of the insulation and instructions that were very clear that you had to insulate both the liquid and suction lines. Because the metering device was at the outdoor condensing unit (?). That could explain similar pressures you may have been seeing; just a thought.

Originally Posted by lytning

I think flare tight has those wrenches. Just Google flare nut torque specs.
I chased leaks all day on a mini that the plumber ran the piping on. Only source of heat and an LG to boot. I really don't know crap about LG's. I sort of wonder why the hi side and lo side pressures are near the same. Couldn't be my Smans. (:-

I think flare tight has those wrenches. Just Google flare nut torque specs.
I chased leaks all day on a mini that the plumber ran the piping on. Only source of heat and an LG to boot. I really don't know crap about LG's. I sort of wonder why the hi side and lo side pressures are near the same. Couldn't be my Smans. (:-

Originally Posted by BBeerme

Huh, that's a very interesting read. Saw an adjustable wrench somewhere that was also a torque wrench. Maybe I'll pick up one of those.

Then I guess I'll need to find out what the correct torques are for the various sizes of tubing.

Huh, that's a very interesting read. Saw an adjustable wrench somewhere that was also a torque wrench. Maybe I'll pick up one of those.

Then I guess I'll need to find out what the correct torques are for the various sizes of tubing.

Originally Posted by Jon MEUS DSG

I teach the installation and service classes for Mitsubishi Mr. Slim and City Multi VRFZ products. Here is the real story and why you DO need torque wrenches, or at least need to use them for a while as a "learning tool" to re-calibrate your "feel".

It is not the higher operating pressure of R410a that necessitates different flares, but the [U]wider operating pressure range[U] of a variable frequency compressor system. Because of the wider temperature and pressure range, the copper that is clamped between the two pieces of brass needs to have a larger surface area in order to maintain enough of the metals elasticity to prevent flattening, and eventually leaking at the joint. The nuts and male parts of the flare are the same as they have always been in our industry. We just used to make our flares in such a way that left us some tolerence for the nut to easily fit over the copper. Now we utilize the entire seating surface with the minimum possible tolerence.

Overtightening is the enemy of mechanical joints in a system such as this. It manifests in the worst possible way. It will pass initial pressure test. It will pass deep vacuum and vacuum rise test. It will then operate leak free for a period of time. I have seen them go as long as 14 months in service. Then comes the call. "It just doesn't seem to run as good as it used to." Nope. It's low on charge. And you find it, either tighten the fitting in question or cut it off and redo it, weigh in correct initial charge, and leave. They they call two weeks later because the next one is leaking. This goes on indefinately unless the flares are all redone at the same time and to correct specifications - including torque.

I too had been making and tightening flares by "feel" for decades. I can't describe what a horrible realization it was the first time I used a torque wrench. I had been grossly over-torquing my flares all along.

When the flares are formed to meet the VRFZ system manufacturer's specifications, and oiled and torqued properly, you can walk away with confidence that the system will remain leak free indefinately.

I hope this helps.

Originally Posted by jpsmith1cm

They are VERY nice in certain situations.


I've found them invaluable for cracked flare nuts on flared TEVs where there isn't enough room to get a block and yoke in there after cutting the cracked flare off.

X2. Always have some on hand.

Originally Posted by herefishy42

One thing that really does make me laugh, are the swedged, pre-flared copper pipe bits on the wholesale shelf that you WELD in - WELD-IN FLARES! LMAO

They are VERY nice in certain situations.


I've found them invaluable for cracked flare nuts on flared TEVs where there isn't enough room to get a block and yoke in there after cutting the cracked flare off.

One thing that really does make me laugh, are the swedged, pre-flared copper pipe bits on the wholesale shelf that you WELD in - WELD-IN FLARES! LMAO

When I worked for the old-timer who really taught me a lot and encouraged me to get my state license, he would have boxes of flare nuts on the trucks. All welded driers would get cut out and flares put in. we discussing this once, and he said, if you put a weld in there, you have a leak. I responded, if you put flare in you have a leak. HA!

I weld everything, and I am glad I don't do AC, work with 410A, nor install those mini-splits with the flare pipe connections (though I did install a couple in my mom's guest house as a gimmie).

The real story on so-called "410a Flares"

I teach the installation and service classes for Mitsubishi Mr. Slim and City Multi VRFZ products. Here is the real story and why you DO need torque wrenches, or at least need to use them for a while as a "learning tool" to re-calibrate your "feel".

It is not the higher operating pressure of R410a that necessitates different flares, but the [U]wider operating pressure range[U] of a variable frequency compressor system. Because of the wider temperature and pressure range, the copper that is clamped between the two pieces of brass needs to have a larger surface area in order to maintain enough of the metals elasticity to prevent flattening, and eventually leaking at the joint. The nuts and male parts of the flare are the same as they have always been in our industry. We just used to make our flares in such a way that left us some tolerence for the nut to easily fit over the copper. Now we utilize the entire seating surface with the minimum possible tolerence.

Overtightening is the enemy of mechanical joints in a system such as this. It manifests in the worst possible way. It will pass initial pressure test. It will pass deep vacuum and vacuum rise test. It will then operate leak free for a period of time. I have seen them go as long as 14 months in service. Then comes the call. "It just doesn't seem to run as good as it used to." Nope. It's low on charge. And you find it, either tighten the fitting in question or cut it off and redo it, weigh in correct initial charge, and leave. They they call two weeks later because the next one is leaking. This goes on indefinately unless the flares are all redone at the same time and to correct specifications - including torque.

I too had been making and tightening flares by "feel" for decades. I can't describe what a horrible realization it was the first time I used a torque wrench. I had been grossly over-torquing my flares all along.

When the flares are formed to meet the VRFZ system manufacturer's specifications, and oiled and torqued properly, you can walk away with confidence that the system will remain leak free indefinately.

I hope this helps.

Originally Posted by ga-hvac-tech

Next time I install a mini... If there is time... I will get a flare fitting from the big box home store and compare it to the one on the mini... maybe take a close up pic and see if they are the same. Anyone who wants to do this and post the pic is welcome to do so... Would like to know if the reps are blowing smoke or not.

The box stores don't sell refrigeration flare nuts. Most of the minis I come across use metric nuts that are made from a CAST 'brass like' material and the ones from the supply house are sae sizes solid brass, and made in the USA. Never had a problem with either type.

I have however had problems with long shouldered steel flare nuts supplied on valve assemblies, replaced with brass.

Admittedly I don't use torque wrenches but do try to use flare wrenches. I still want one nonetheless.

Hopefully someone will post some pics...

Originally Posted by ga-hvac-tech

Maybe we will get your wife to explain this to you... <grin>

What I understand (from manufacturers reps, never actually did a comparison) is the physical size of the flare is a little larger. Think like this: When one does a flare, they leave a little of the CO tube sticking out of the clamp, this is the part that is 'flared'--that is; bent to the angle. And we know if we hang out too much CO tube... the flare will be too wide and not pull back into the nut.
Again as I understand it... a proper 410 flare is just a little wider than a conventional flare.

Next time I install a mini... If there is time... I will get a flare fitting from the big box home store and compare it to the one on the mini... maybe take a close up pic and see if they are the same. Anyone who wants to do this and post the pic is welcome to do so... Would like to know if the reps are blowing smoke or not.

I guess comparing them will only be the real truth!! But I have the yellow jacket flaring tool that measures the the depth and deburrs the flare all in one and makes a perfect flare every time. Well I was told back when I got it "oh it even makes the 410a flares". Now. I used this thing plenty of times for other things besides 410a systems so that means if the 410a flare cone was wider then my regular nut wouldn't slide over it! I always thought all flares were the same just the nut was actually fatter and more bulky but the actual flare cone would be the same

Originally Posted by air1

All refrigeration flares are 45 degree flares. There is no difference for the R410A flare fittings. Manufactures of R410A systems do have specific procedures and tools they want used because of the higher pressures involved but the flares are not different. They recommend a clutch type flare tool and torque wrenches to prevent flattening of the copper flare. They are really just trying to make sure the flares are done right, not different.
If I'm wrong then please enlighten me. It wouldn't be the first time I was wrong. Just ask my wife.

Maybe we will get your wife to explain this to you... <grin>

What I understand (from manufacturers reps, never actually did a comparison) is the physical size of the flare is a little larger. Think like this: When one does a flare, they leave a little of the CO tube sticking out of the clamp, this is the part that is 'flared'--that is; bent to the angle. And we know if we hang out too much CO tube... the flare will be too wide and not pull back into the nut.
Again as I understand it... a proper 410 flare is just a little wider than a conventional flare.

Next time I install a mini... If there is time... I will get a flare fitting from the big box home store and compare it to the one on the mini... maybe take a close up pic and see if they are the same. Anyone who wants to do this and post the pic is welcome to do so... Would like to know if the reps are blowing smoke or not.

Originally Posted by ga-hvac-tech

As I understand it:

An 'R-410 flare' is made a little different... to fit a flare fitting and under a flare nut that are also a little different.

The part which is flared (call it the cone) is a small amount wider... thus more contact space to hold in more pressure.

You and I do agree on cutting off the flare and flare nut from pre-made linesets... then make a new flare and use the flare nut that came with the mini.

All refrigeration flares are 45 degree flares. There is no difference for the R410A flare fittings. Manufactures of R410A systems do have specific procedures and tools they want used because of the higher pressures involved but the flares are not different. They recommend a clutch type flare tool and torque wrenches to prevent flattening of the copper flare. They are really just trying to make sure the flares are done right, not different.
If I'm wrong then please enlighten me. It wouldn't be the first time I was wrong. Just ask my wife.

Originally Posted by carmon

Really...... a good flare will never leak.... 410-22 -507--134a---404- 502.... 00ps did i sat 502

Yes, I agree... work done PROPERLY, and by someone WHO TRIES... performs as it should.

Now tell me how many folks out there wearing the shoes of techs actually do work properly and try every day... Yeah, I know also.

IMO the industry sometimes creates parts to compensate for the quality of the average worker... not that there are not better folks doing the work... (you and I and most of H-talk).

I put in, I think, a dozen give or take mini's last year... have not heard a word from any of them concerning leaks. Pays to do the flares properly...
BTW: I have not bought a flare nut torque wrench yet... may get one if I see one on sale somewhere.

Originally Posted by ga-hvac-tech

As I understand it:

An 'R-410 flare' is made a little different... to fit a flare fitting and under a flare nut that are also a little different.

The part which is flared (call it the cone) is a small amount wider... thus more contact space to hold in more pressure.

You and I do agree on cutting off the flare and flare nut from pre-made linesets... then make a new flare and use the flare nut that came with the mini.

Really...... a good flare will never leak.... 410-22 -507--134a---404- 502.... 00ps did i sat 502

Originally Posted by air1

I don't think there is such a thing as a R410A flare nut. They all take the same size wrenches unless they're metric. I think what GA-HVAC-TECH was referring to is that the flares and the flare nuts on the line sets with flares are of poor quality. They should be removed and you should use a quality flare nut and make your flare using the recommended tools and methods as specified by the R410A mini-splits manufactures. Meaning you should use a gauge for your flares and torque to manufacture specifications.
The torque wrenches should work on all flare nuts.

As I understand it:

An 'R-410 flare' is made a little different... to fit a flare fitting and under a flare nut that are also a little different.

The part which is flared (call it the cone) is a small amount wider... thus more contact space to hold in more pressure.

You and I do agree on cutting off the flare and flare nut from pre-made linesets... then make a new flare and use the flare nut that came with the mini.

Flare nut torque isn't going to be refrigerant specific.

It's size specific.

If you get an adjustable wrench and all the needed sizes, you can tighten any flare nut with that setup.