flare connection failure

[philjd26]

hi
i had a flare connection blow off on me on a r410a system causing fridge burn on my hand, i was wondering what causes these connections to fail...

it looks like the flare was forced into its original dimension

any thougths

rgrds phil

[cadwaladr]

what type/make of flaring kit are you using,its very important with 410,no margin for error at those pressures/

[DEVIL]

If you tighten to much the hex then the flare gets damaged ant the wall of the copped gets thinner , and just touching the pile might make it rupture

[philjd26]

i did not do the original flare but if i did would use a torque engaged tool, and would not have over tightened but did however i did disconnect and reconnect this particular flare....

could the intergrity of the copper have already been damaged from installation and by me tampering with it caused complete failure...??

i have had 2 leaking flares on this system so far!!!!

rgrds phil

[sedgy]

hi, I have allways favoured the flairing block that holds the pipe by clamping it all the way round , insted of 2 halves that are clamped together, also the cone had flats on it so with a little oil onit it sweeps the copper into shape, when connectinga little oil on each side of the flair helps it to seat properly, -happy flairing

[chemi-cool]

It could be of low quality brass.

You can heat the copper pipe and then tighten it carefully.

heating the copper makes it softer and you will require less torque

[sedgy]

to aneal the copper its best to heat to cherry red then quench in water, you can easly clean off the black coating, before you flair

[paul thompson]

?????????????

[Brian_UK]

Was it the copper that failed or the flare nut?

[Yuri B.]

Preparing the pipe's end is hardening the copper. So it may indeed be good heating it after it is ready to soften it (take off the inner strenght in the metal). Heating up and then qwenching in water would temper the copper, not soften it.

[Grizzly]

Sorry Yuri.
Sedgy is correct where annealing copper is concerned Quenching in water or allowing to cool in air.
Either are as effective and achieve the same results!
Grizzly

[US Iceman]

I have not worked with R-410a, but doesn't that require thicker tube wall tubing?

Failure of flares is typically due to them not being made properly on soft tubing. Sometimes people like to crank the flare tool down too far and this thins out the metal next to the radius of the flare to tube joint. Sometimes the tubing will pull right out of the flare nut and straighten the flare also.

[glenn1340]

I use an eccentric cone flaring tool, it`s got an integral clutch so you can`t apply to much pressure and stress the flare.
Much easier to use too

[philjd26]

@iceman=i think the thinning of the copper is what caused the flare to fail, it looks like with pressure it had over come the strenght of the copper and slipped away from the connection. i got a really nasty fridge burn as i was feeling around the connection when noticed a hissing sound..... it was the liquid line with r410a, ouch!!! -50 to -60c hit the palm of my hand!!! out of work a week and feeling really down about the hole thing...sometimes i hate this tradel!!!!

once bitten twice shy, big time!!!!

@ brian, it was the copper that failed.

[DEVIL]

@iceman=i think the thinning of the copper is what caused the flare to fail, it looks like with pressure it had over come the strenght of the copper and slipped away from the connection. i got a really nasty fridge burn as i was feeling around the connection when noticed a hissing sound..... it was the liquid line with r410a, ouch!!! -50 to -60c hit the palm of my hand!!! out of work a week and feeling really down about the hole thing...sometimes i hate this tradel!!!!

once bitten twice shy, big time!!!!

@ brian, it was the copper that failed.

The symptom you are explaining is exactly what i explained , a normal flare (that normally would handle ok) if it is overtightened will make the wall ticklishness get smaller and get a bigger external diameter until it pushes on the side and then it can't expand any more so it expands on the base of the flare pushing the pipe a little bit outside , but wen it pushes it gets thiner on the base of the flare , and then a little movement and it ruptures, it's not the coper that is the problem, it is the flare (in case it is a little big biger) and the over tightening that dose the rest.

[Yuri B.]

the palm of my hand!!! out of work a week and feeling really down

I dont like bands when I get hurt my hands somehow (not *****s till now, mechanically), prefer soft cotton gloves on them, after having applied a balm - when going to bed.

[US Iceman]

Two actions typically happen: either the flare is pulled out through the flare nut or the tubing breaks of at the flare nut. Both tend to be from incorrect flares being made.

[Brian_UK]

While I fully agree with the cause of this failure being poor workmanship can I pose another angle?

Is it possible in certain circumstances for the copper to work harden during normal usage, for instance... ?

A flare joint has been made onto a machine which vibrates and the copper tube have been secured with brackets which do not provide any anti-vibration damping.

The action of the machine running then starts working on the weakest point which is the edge of the flared joint.

[VRVIII]

hi
i had a flare connection blow off on me on a r410a system causing fridge burn on my hand, i was wondering what causes these connections to fail...

it looks like the flare was forced into its original dimension

any thougths

rgrds phil

Hi,

The most common reasons for flare leaks/fracture are:

• Over compressing copper when forming the flare, most a/c manufactures specify that a 410a clutch type flaring tool must be used to prevent this.

• Over tightening flare nut, which can eventually force the pipe back through the flare nut (more common on ¼”) or fractures pipe . Again most a/c manufactures specify a torque wrench must be used. I agree with Devil/Iceman and think this is what has happened in your case.

• Formed flare is too small, due to incorrect flaring block pipe position when forming flare.

• Failing to de bur pipe end prior to forming flare

• Poor quality copper pipe

Water mixed with detergent should not be used for leak checking flares, this can result in moisture entering threads due to capillary action which in turn can freeze and fracture flare nut. Only the correct leak detection fluid should be used.

[VRVIII]

While I fully agree with the cause of this failure being poor workmanship can I pose another angle?

Is it possible in certain circumstances for the copper to work harden during normal usage, for instance... ?

A flare joint has been made onto a machine which vibrates and the copper tube have been secured with brackets which do not provide any anti-vibration damping.

The action of the machine running then starts working on the weakest point which is the edge of the flared joint.

This is another valid point Brian, depending on equipment vibration and of course the use of fresh air sky hook fixings

[US Iceman]

I agree with the breakage factor due to work hardening. The vibration causes a similar effect just like bending tubing in the same place causes it to harden. Once this occurs it does not take much to cause the flare to break at the weakest point, which is usually the radius of the tube to flare joint.

Another installation trick is to allow three directions of the tubing run. This provides some flexibility in the tubing to absorb and distribute the vibration away from the hard connections (the flare nuts). If the tubing is installed in a short direct fashion the tubing has less flexibility.

[philjd26]

thanks for reply chaps, more iv an idea of what to look out for...extra care should be taking when installing pipework for r410, pressures are abnormal to previous refrigerant...

and it was a 1/4 pipe that failed, nice high pressure liquid on to my jazz band.

rgrds phil

[Magoo]

I use one of those eccentric flaring things with a clutch/torque trip, and on standard pipe. Not re-cycled pipe which tends to be harder. Never had a problem if tube reemed and cleaned correctly.
US Iceman you must have trained with Carrier somewhere along the line with comment of "three directional changes " comment. Standard practise and no need for vibration elliminators theory.
The comment about heating and qwenching in water is a no no., will harden the pipe. Apart from adding steam/water to pipe and system.
From my piont of veiw I only use pure Anaconda non re-cycled pipe, expensive, but no call back failures. I will leave the junk pipe for plumbers that cannot weld with silfos anyway.

[DEVIL]

While I fully agree with the cause of this failure being poor workmanship can I pose another angle?

Is it possible in certain circumstances for the copper to work harden during normal usage, for instance... ?

A flare joint has been made onto a machine which vibrates and the copper tube have been secured with brackets which do not provide any anti-vibration damping.

The action of the machine running then starts working on the weakest point which is the edge of the flared joint.

For that type of case i sow on one unit some time ago (it wasn't a known brand and don't remember exactly) that on the pipe was provided tome type of brass bushing that on one end had the design of the flare (so the back of the flare can sit on it) and long like for 20 mm, so that actually reduced the stress on the neck of the flare

[Tony]

Hi philjd26,

i got a really nasty fridge burn as i was feeling around the connection when noticed a hissing sound..... it was the liquid line with r410a, ouch!!! -50 to -60c hit the palm of my hand!!!

I hope you were wearing your PPE!!!!!!!

[sedgy]

mr magoo, about your statment about heating copper=
carbon sreel if heated + quenched in water WILL harden it
copper heated+ quenched in water will soffen it= have you tried it?

[philjd26]

Hi philjd26,



I hope you were wearing your PPE!!!!!!!

i wish, out for 2 weeks!!! i will be in future thats for sure.

[US Iceman]

US Iceman you must have trained with Carrier somewhere along the line with comment of "three directional changes " comment. Standard practice and no need for vibration eliminators theory.

To be honest, I did attend some Carrier and Trane schools amongst others. I don't remember where I heard that but I have spent enough time pulling wrenches for a living to have picked up some things also.

There is nothing more frustrating than trying solve a pipe cracking issue on a large chiller produced by a seemingly reputable manufacturer either to learn a few tricks here and there also.

Sounds like you have covered much the same path I have Magoo.

[Magoo]

Hi US Iceman. Happy New Year
Yes, seems we have both done the same hard yards, given the similar ages.
Nothing more frustrating than going to a problem and finding broken pipework on a standard manufactured system.
Give me a pipe layout with long radius cold bent pipework, and welded with out cherry red pipework. By someone that understands copper pipe welding.

magoo

[lowcool]

with the dramas of 410 the only flared connections are at the unit,the rest i weld if possible.
heating the pipe causes the molecules to expand and by quenching or cooling it holds
the molecules in this position thus making the copper softer,thats what i learnt anyway
cheers

[G unit]

But really folks, if the 1st flare failed, i would have suspected low quality copper, supposing of course i was happy with my flare.. so i would have cut the pipe work back, brazed in a new section of pipe with a puka flare on it.. and bosh jobs a good'un

[freezetech]

i cut out all flare nuts out of 410 systems and use vulkan lokring fittings fitted loads now and no callbacks

exept service ports of course