Testing for leaks in oil line

[Oilboil]

I wonder if someone can reassure me about this...

Our domestic oil tank was recently found to be empty many weeks ahead of schedule. There was no sign of theft and our engineer queried a leak in the underground upvc pipe that links the tank to the boiler.

He isolated the tank and using a Rothenberger pump pressurized the line to 24 bar. Just over two days later this is down to 10 bar.

He assures me that this drop is normal but I have two worries:

1. He appears to think that he only applied just over 2 bar of pressure

2. As far as I can from some light Googling, these lines should not have more than about 8bar applied for more than three hours

Please reassure me that the test as described above is appropriate and unlikely to have caused (further) damage to the line.

Many thanks in advance

 

[Dotty]

You sure it weren't 2.4 and 1.0 bar?

 

[Oilboil]

That's what I thought at first but the original "24" setting corresponded to around 350psi on the pump's guage.

 

[Dotty]

If it was copper or steel it should only be pressured to 1.0 bar and checked for a drop after 15 minutes. If a drop is detected then the pipework should be exposed and replaced. If no loss is detected then the test should be left on for a further 30 minutes.

Plastic pipework is dependant on the manufacturers recommendations. I don't believe any manufacturer would advise 24 bar over a period of days!

 

[SimonG]

Which is one reason underground pipework should be sleeved. Leak would be visible at atleast one end of the sleeving. Which would also be easy to replace the line through the sleeving.

 

[Dotty]

I've just looked at Qual-Oil pipe manufactured by Pipelife.

Exactly the same test as above.

Not sure what your boys thinking is..........

 

[Dotty]

Which is one reason underground pipework should be sleeved. Leak would be visible at atleast one end of the sleeving. Which would also be easy to replace the line through the sleeving.

Amen to that. Costs a wee bit more but by 'eck does it save some hassle!

 

[Best]

As above ^^ the blue water pipe, 20mm or 25mm normally and have it above ground a few inches at each end and that will allow any leak to show. Common sense method that should have been made compulsory years ago.

 

[Best]

Amen to that. Costs a wee bit more but by 'eck does it save some hassle!

Think it is just about a pound a metre, so not much on a job. I prefer to still use pvc coated copper oil line and put it inside 25mm water pipe

 

[SimonG]

Think it is just about a pound a metre, so not much on a job. I prefer to still use pvc coated copper oil line and put it inside 25mm water pipe

That's all I use. 10mm pvc coated copper inside 25mm alkathene.

Had one in January. Only a couple of metres, but the old pulled out and new through with no hassle.

 

[SimonG]

Think it is just about a pound a metre, so not much on a job. I prefer to still use pvc coated copper oil line and put it inside 25mm water pipe

That's all I use. 10mm pvc coated copper inside 25mm alkathene.

Had one in January. Only a couple of metres, but the old pulled out and new through with no hassle.

 

[Oilboil]

Thanks for the replies. The line is in a pvcu conduit so replacement should be straightforward. I suspect replacement would not have been necessary 48 hours ago. Will try and post photo of the pressure guage just to double check.

 

[Best]

That's all I use. 10mm pvc coated copper inside 25mm alkathene.

Had one in January. Only a couple of metres, but the old pulled out and new through with no hassle.

You were lucky it wasn't the old 3/8" alkathene pipe I used to use with bare 10mm copper pushed through it! :smile: Was near a tight fit and the longer the run of pipe, the tighter it became to push through.

 

[Oilboil]

Here's a photo of the gauge from a little over 24 hours ago. The red needle was the starting pressure and the black one where it fell to over the following 24 hours. It's now a little bit lower than that.

By my reading it is 24 bar/350 psi/2.5 MPa - or am I wrong.

If the oil line is Qual-oil - and I think it is, this pressure would invalidate the warranty - so I'm guessing that it would need to be replaced - and likely at the engineer's expense...


Not sure if that worked, here's a link to the image:
https://s14.postimg.org/6iqv9kn0h/20170310_193011.jpg

 

[Last Plumber]

Whilst you're on this subject, does nobody test oil lines with a vacuums guage anymore ?

 

[ShaunCorbs]

I read 14 bar on the gauge I would say the pressure was ok bit high but should be able to cope

Depends what the manufacturer says to test at

And shouldn't drop at any pressure big drop = leak

And the system according to manufacture (qual oil) can take 200 bar breaking strength

 

[Oilboil]

Currently 14 bar but it started up where the red needle was so I read it as having been 24.

Good to know that it's rated upto 200 bar but I note that the warranty is invalidated much lower than that...

 

[Oilboil]

Currently 14 bar but it started up where the red needle was so I read it as having been 24.

Good to know that it's rated upto 200 bar but I note that the warranty is invalidated much lower than that...

 

[ShaunCorbs]

Currently 14 bar but it started up where the red needle was so I read it as having been 24.

Good to know that it's rated upto 200 bar but I note that the warranty is invalidated much lower than that...

Sorry to say your warrentys gone as it hasn't been sleeved

did the pressure drop to that or did he let some out ?

 

[Oilboil]

I think it is sleeved.

The pressure dropped to that over the course of about 48 hours.

 

[SimonG]

I don't like the plastic oil pipe. It can't come to the surface so you need covers at each end as it's not uv proof.

 

[ShaunCorbs]

I think it is sleeved.

The pressure dropped to that over the course of about 48 hours.

Should drop that much maybe .5bar max over 24 hours

 

[WHPES]

I just replaced a length of 10mm bare copper pipe which had been in plastic sleeving today. The pipe hand rotted through and was leaking oil.

 

[tamz]

Plastic pipe: you don't have a leak.
A. Your engineer didn't know basic principles of pressure testing plastic pipe.
B. I bet you were all over him like a rash
C. Where there is blame there is claim.......unlucky; ladbrooks wouldn't take a bet on a leak or damage with the test. Your pipe is fine but it is your prerogative to challenge that in court if you have the spare cash.

The pressure on an oil line would be doing well to exceed 0.2 bar ( i gave it the benefit of the doubt there and added another 0.1) so you could in reality, hold a joint together with some juicy fruit (old fashioned chewing gum made by wriggleys).

Back to basics. Plastic pipe expands under pressure and the max time it should ever be tested to is 180 mins or 120 depending on the test: say 12 bar test 0.6 bar drop after 30 mins 0.8 after 2 1/2hrs and the drop will continue with time, or 12 bar initial then drop to 4 bar no loss after 90 mins.
This IS basic stuff for ALL plastics.



Since the world revolves around the internet google the numpty and i'm sure you'll find it or if you are stuck ring the pipe manu and ask for the test procedure.
They will get back to you in 2 days or so in which time your pressure will have went up or down depending how you feel but doing so may have invalidated your warranty.
Do you call it a day and think he'll with it without manufacurers support (is He really listening) or just see if you can make another 30+ years before your planting

 

[tamz]

I just replaced a length of 10mm bare copper pipe which had been in plastic sleeving today. The pipe hand rotted through and was leaking oil.

What kind of shyte do you have in the ground down in the shires that eats copper