Aircon pipes spanner size

[roys]

I think an important point here is experience and feel, if you have these then there is a good chance you will get the torque in the right ball park, get a 20 stone gorilla of a fitter tightening down a 4BA brass nut and bolt then be ready to replace it as it has stripped, on the the other get some gamer who has never been out of his bedroom tightening down the 32mm nuts on the back actor of a JCB then there is a fair chance it will not be tight enough.

 

[johnb2713]

I think an important point here is experience and feel, if you have these then there is a good chance you will get the torque in the right ball park, get a 20 stone gorilla of a fitter tightening down a 4BA brass nut and bolt then be ready to replace it as it has stripped, on the the other get some gamer who has never been out of his bedroom tightening down the 32mm nuts on the back actor of a JCB then there is a fair chance it will not be tight enough.

Totally agree.

 

[michael8554]

Coincidently a recent MOT suggested I should change the front brake pads on my car.
Tried to loosen the wheel nuts with the 12" long wrench in the toolkit.
No go, even jumping on it.
In the end it required a socket and a 3 foot extension, and jumping on it .
Went around all four wheels and loosened them and retightened with the tool.
The wheel nuts had been "torqued" by the "professionals" at the tyre depot.
What hope would I have had of changing a flat on the road ?

 

[Andy™]

The wheel nuts had been "torqued" by the "professionals" at the tyre depot.

seen it many times when its rattle gunned to FT then they use a torque bar. and they still don't understand the problem

 

[Marvo]

I’m sure all of what you say is theoretically true, in practice however not really needed. I’ve just had £28,000 of AC installed in my commercial premises and all of the joints were tightened by the Armstrong method and an adjustable spanner. This was installed by an AC engineer who I have used over the last 30 years, not once has a pipe joint ever leaked or failed. My home installation consists of some 13 split Mitsubishi Heavy Industry units, again I only used an adjustable spanner and arm power.
The same style of connection is used on car brake lines where pressures of 10,000 psi and above are easily achieved, I don’t feel refrigerant gasses getting to the dizzy heights of 400 psi max are really going to test the materials or joint integrity to any great degree.
Only my viewpoint, I am an engineer but not an AC engineer and call on practical experience rather than a university theory book.

Car brake lines use a 'bubble flare' on steel lines which is different to a HVAC 45° flare with an acme threaded brass nut on soft drawn copper lines. Occasionally you'll see 'double flares' used in HVAC as well. As far as torque settings go it's the same debate as it is in the electrical industry... is it necessary to use a torque calibrated tool or is experience and feel sufficient.

The manufacturers go to great lengths to test the ideal torque and if you follow their recommendations you're covered if a correctly made flare or wire termination fails. I generally make a point of using torque tools just because it's almost no extra work and if there is a leak or burned termination I know there was nothing extra I could have done to prevent it.