Why Is It? - Seeing round corners

[Brian_UK]

Why is it that?

Whenever a flare nut fails and causes a system to leak that the visible fracture line is hidden on the other side of the nut.

1. Is this because I had bad thoughts today ?
2. Is it because the great fridgeman in the sky has got it in for me ?
3. Is it because that's where leaks go when no-ones looking ?
4. Is it because my eyesight is failing ?
5. Or am I just unlucky ?

[shogun7]

Why is it that?

Whenever a flare nut fails and causes a system to leak that the visible fracture line is hidden on the other side of the nut.

1. Is this because I had bad thoughts today ?
2. Is it because the great fridgeman in the sky has got it in for me ?
3. Is it because that's where leaks go when no-ones looking ?
4. Is it because my eyesight is failing ?
5. Or am I just unlucky ?

I heard that was a prominent problem in the UK
The solution is to install flare nuts wth the visible fracture line so it always shows, like we do in the good ole US of A. You need to get the ones with the stops in them.

[Peter_1]

They mostly crack - at least, that's my experience - because water can enter in the thread of the 'low suction nut'.
I always use leak lock (that blue stuff) on the threat - only the threat, not the flare itself - of a nut so that a seal is formed and water can't enter the thread.

Saw many times nuts of others techs who spread generously the leak-lock on the flare itself and even leak-Lock in the tube of course.

[Coolie]

There are a few reasons why a flare nut cracks:

1. A torque wrench wasn't used
The nut was overtightened.

2. The pipe work connected to the unit is too rigid. Buy this I mean it was supported to tightly and too close to the flare conection. I always leave about a foot before any flare nut.
The vibration from the unit and the costant starting of the fan (indoor unit) will over time anneal the brass or copper (in the case of a join) and cause the nut to become britle and develope a crack. This will also cause braised joints to fail.
Daiken recomends that if this happens you should install a Ptrap or u bend right before the nut or join. ( I bet that does wonders for the oil return)

3. The flare nut is not lagged.
The brass reacts with chemicals in the air, eg sovents from carpet glue or cleaning solutions, airfresheners or just general polution. The first sign to look out for of this chemical reaction taking place is the flare nuts turn black.
Always insulate the flare nuts. Not only does this prevent condensation dripping on the ceiling, it actually gaurds the nuts from the atmosphere.

4. And, like Peter says, the constant freezing and thawing of the flare nut on the low side. But even if water does not get into the thread, the sudden changes in tempreture will have an effect on the the nut.

[Latte]

[QUOTE=Brian_UK]Why is it that?

Whenever a flare nut fails and causes a system to leak that the visible fracture line is hidden on the other side of the nut.

Sorry Brian, Can't answer that one but it is probably the same reason that when you have a unit with two condenser fans motors the motors that alway seizes is the one that you cannot get to because the compressor is in the way.

Regards

Raymond

[chemi-cool]

And why is it that when a slice of bread falls down, the side with the butter will hit the carpet?

Its called, Murphy`s law.

Thats life I'm afraid.

Chemi

[Peter_1]

Or a 3 phase fan: 50% chance that it runs in the right direction but it run almost always in the wrong direction.