3/8 and 5/8 Copper tubing Flare Nut Size?

jonathan75 · May 13, 2014

I just ordered a Pioneer mini split and want to torque the flare nuts to factory specs using a Flare Nut Crows Foot and my torque wrench. I Googled for over a hour and can not find the answer to my question. I want to make sure I have everything ready for when it gets here so I am getting all the tools ready now and can't wait to check the size when it comes in.

I called the company I ordered from to ask what is the size of the flare nuts. This is what he told me but I want to confirm. Trust but verify. He did not sound extra sure. Is this correct?

3/8 Copper Line = 7/8 Flare Nut Size
5/8 Copper Line = 1 1/8 Flare Nut Size

So I ordered this before the cutoff today. Hope it is right.

Stanley Proto J5336FL 12 Point Flare Nut Crowfoot Wrench 1/2" Drive 1-1/8"
http://amzn.com/B0026H8AI4

And was thinking about this set from Sears for the 7/8" size.

Craftsman 10 pc. Fractional Crowfoot Flare Nut Wrench Set
http://www.sears.com/craftsman-10-p...1x000001&kpid=00942049000&kispla=00942049000P

anthony666 · May 13, 2014

a) don't use a 12 point on a brass nut
b) get a regular wrench and crank it down good and tight and call it a day

jonathan75 · May 13, 2014

anthony666 said:
a) don't use a 12 point on a brass nut
b) get a regular wrench and crank it down good and tight and call it a day

It says in the description "Applies up to 15pct more torque to fastener. -High strength, thin wall design. -Reduces risk of fastener rounding." But is brass too soft for these qualities to be effective?

I couldn't find anything other then 12 point when I looked in 1 1/8 size. But I did just find another brand cheaper but still 12 point.

Which is better? Stanley Proto from my first post or this JH Williams?

http://amzn.com/B005VNLG18

mygarageone · May 13, 2014

You can use two crescent wrenches and be just fine. I have never heard of anyone torquing flare nuts for anything . But you do want the extra heavy duty flare nuts ( forged )

jonathan75 · May 13, 2014

mygarageone said:
You can use two crescent wrenches and be just fine. I have never heard of anyone torquing flare nuts for anything . But you do want the extra heavy duty flare nuts ( forged )

I read that some people have over tightened and split the end of the copper line. I figured since it was my first time working with flares I should probably torque it since I don't have a feel for it yet.

Can I trash the flare nuts that come with the line kit and purchase extra heavy duty from a local supply house? Should the thread size be standard?

jonathan75 · May 13, 2014

I still don't know for sure what size is the flare nut for 3/8 and 5/8 brass pipe. Does anyone use them daily that knows the size or can check for me. I tried very hard to search for the answer online and could not find it.

mygarageone · May 14, 2014

Actualy the flare nuts that come with your line , should be fine . As far as splitting the copper , that can happen but lots of force . Or a bad flare.

jonathan75 · May 14, 2014

mygarageone said:
Actualy the flare nuts that come with your line , should be fine . As far as splitting the copper , that can happen but lots of force . Or a bad flare.

For the flares I will use the Yellow Jacket 60278 Deluxe 45. I read in many places and reviews it is best not to trust the factory flares, plus I would like to cut the line set shorter.

http://www.amazon.com/gp/product/B002SB5RMA/?tag=atomicindus08-20

monkeyspanners · May 14, 2014

Often the flare nuts are metric across the flats even thought the thread and pipe hole are in inches.

Generally i use an 8" adjustable on 3/8" nuts and probably a 12" on the 5/8 nut. You should be able to turn the nut all the way home by hand, meaning that the pipe is in line with the fitting, the nut should not have to pull the pipe into place.

I don't use a torque wrench on them but i have been doing them up for 25+ years so have a feel for them.

jonathan75 · May 14, 2014

monkeyspanners said:
Often the flare nuts are metric across the flats even thought the thread and pipe hole are in inches.

Generally i use an 8" adjustable on 3/8" nuts and probably a 12" on the 5/8 nut. You should be able to turn the nut all the way home by hand, meaning that the pipe is in line with the fitting, the nut should not have to pull the pipe into place.

I don't use a torque wrench on them but i have been doing them up for 25+ years so have a feel for them.

Thank you for the feedback monkeyspanners. I hope to get a feel for it but I don't think I will be doing this often enough. Today I picked up some Nylog Blue to help seal it to be on the safe side. The supply house also was nice enough to give me some flare nuts. Here is the results of what I found.

Supply House Flare Nuts (Unknown Brand)
3/8 Flare Nut = 13/16
5/8 Flare Nut = 1 1/16

I am not sure what to think now. The Yellow Jacket torque tool kit is all metric, Pioneer tech support told me theirs were SAE 7/8 and 1 1/8 and the ones I picked up today was SAE but 13/16 and 1 1/16. I sure wish this stuff was standard. Trying to prepare in advance is not easy.

mygarageone · May 14, 2014

You are way overthinking this whole thing.

Tarheelgarage · May 14, 2014

mygarageone said:
You are way overthinking this whole thing.

No he's not. He needs to also braze the flare nuts to ensure a tight seal.... :bounce:

jonathan75 · May 14, 2014

mygarageone said:
You are way overthinking this whole thing.

Yeah I know I am. It is a curse really. Well I guess it does help me with my job. That is the reason I am good at what I do.

I will start a thread on this install since it is a not very popular unit. Give others a chance to check Pioneer out.

monkeyspanners · May 15, 2014

A lot of the mini split makers are Japanese, so the nuts are generally metric. They are also stronger to cope with R410A running pressures. Use the nuts that come with the unit. They can run up to 620psi in heating model so the strength test we (should) do here on new pipework would be around 800/900psi!!! hence the stronger nuts.
Its a shame they don't just give a hand tight then 60' or 90' degree turn.

jonathan75 · May 15, 2014

HighSeer.com told me wrong and their nuts are strange sizes for mine. But the HVAC supply house nuts fit much better.

Pioneer Line Kit Flare Nuts
3/8 Line = 22mm or 7/8" (Sloppy fit, 22mm slightly better fit over 7/8")
5/8 Line = 27mm or 1 1/16" (Okay fit but not perfect)

HVAC Supply House Flare Nuts
3/8 Line = 21mm or 13/16" (Very snug and perfect fit)
5/8 Line = 27mm or 1 1/16" (Very snug and perfect fit)

jonathan75 · Jun 9, 2014

I forgot to update. In the end I just used a German torque spec of Gute In Tight. Between the German torque spec by hand and copious amounts of Nylog I was leak free.

It is now safe to go outside. But I warn you, I will bring out the torque wrench another day! :willy_nil

Jackfre · Jun 9, 2014

Did you use the Ny-loc on the face of the flares? If so, I am surprised that it is leak free. Brass to brass on the flare fitting does not require pipe dope of any kind.

jonathan75 · Jun 9, 2014

Jackfre said:
Did you use the Ny-loc on the face of the flares? If so, I am surprised that it is leak free. Brass to brass on the flare fitting does not require pipe dope of any kind.

I did it just like the video in the link below. The stuff is great. I put it everywhere, I even put it on my face like war paint.

LS6 Tommy · Jun 9, 2014

Not to sound insulting, but sealant is never needed on any part of a flare connection, period. If you're finding you need to use a sealant on a flare because it leaks, you're not making the flares correctly. You can always get copper flare washers if you want to get a little extra "squeeze" on a connection.

As for tightening the flare nuts, use proper flare wrenches when you can or open end wrenches & tighten by hand. Use adjustable "Crescent" wrenches if that's all you have. A crow's foot on a torque wrench won't read accurately anyway...

Tommy

joe_padavano · Jun 9, 2014

LS6 Tommy said:
A crow's foot on a torque wrench won't read accurately anyway...

And you started out so well with the "don't use sealer" comment.

LS6 Tommy · Jun 9, 2014

joe_padavano said:
And you started out so well with the "don't use sealer" comment.

Yeah, I should have clarified that unless you use the crow's foot 90* to the end of the torque wrench, the reading won't be accurate. It CAN'T be accurate. You're extending the length of the wrench from the center of the fastener. Even when you do turn a crow's foot 90*, it's not 100% as accurate as putting the torque wrench directly on the fastener with a socket, but it works for most "non-critical" applications.

Tommy

jonathan75 · Jun 11, 2014

LS6 Tommy said:
Not to sound insulting, but sealant is never needed on any part of a flare connection, period. If you're finding you need to use a sealant on a flare because it leaks, you're not making the flares correctly. You can always get copper flare washers if you want to get a little extra "squeeze" on a connection.

As for tightening the flare nuts, use proper flare wrenches when you can or open end wrenches & tighten by hand. Use adjustable "Crescent" wrenches if that's all you have. A crow's foot on a torque wrench won't read accurately anyway...

Tommy

It was the very first flare in my whole life that I did for this install. I wanted every possible advantage to ensure I would be leak free. Numerous positive reviews from professional installers led me to use Nylog. Since I am leak free and got down to 97 microns I really can't complain and wouldn't hesitate to use it again.

I used correct combination wrenches for every connection except for one size I didn't have I used an adjustable. But if I did use the crows foot I would of used the proper formula to compensate on the torque wrench for use with a crows foot.

LS6 Tommy · Jul 3, 2014

That must be on HELL of a vacuum pump...

Tommy

jonathan75 · Jul 3, 2014

LS6 Tommy said:
That must be on HELL of a vacuum pump...

Tommy

It was my neighbors pump, but it was fresh out the box and brand new. I plan to buy a used JB pump for myself.

3/8 and 5/8 Copper tubing Flare Nut Size?

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