Thermal expansion and 90 elbow end feed copper fittings

[wavetrain]

I am looking at a recent professional CH installation where there are very long runs of 22mm copper. There are regular offsets to take up the thermal expansion (2mm at an elbow), but the offsets are short so it seems to be just the fittings that are bending to take up the thermal expansion rather than the offset pipe bending .

I took hot and cold measurments today and will calculate the angle the elbows bend later.

I looked on Yorkshire fittings website for the maximum one should allow an end feed elbow to be thermally cycled by but no info could be seen.

Does anyone have a web link to this data?

 

[doitall]

You should Never use fittings for an change of direction expansion, end of story.

That applies to soldered or screwed joints.

 

[wavetrain]

Not sure what you are referring to doitall.

I am referring to offsets that are often used to allow for expansion. This is taken from Yorkshire Fittings brochure:

As the offset shortens so the stress on the fitting increases, how much is too much?

 

[billy bob]

Try looking at www.ukcopperboard.co.uk also www.cda.org.uk you should find the answer if not you can contact them to get the answer.

 

[wavetrain]

Thanks for that info, having looked through it I have not found the answer so far however.

 

[Doctor Drivel]

Try inserting a length of plastic pipe using brass compression joints. Give lots of slack.

 

[doitall]

Thanks for that info, having looked through it I have not found the answer so far however.

I repeat; You should Never use fittings for an change of direction expansion, end of story.

The example shown are all pulled bends.

 

[billy bob]

You can buy expansion bellows to do the job

 

[doitall]

You can buy expansion bellows do do the job

That is the proper way to do the job provided you anchor the pipe down.

You can also pull bends as per the examples.

By fittings I mean bends and elbows which was the original question.

 

[billy bob]

You can buy expansion bellows do do the job

That is the proper way to do the job provided you anchor the pipe down.

You can also pull bends as per the examples.

By fittings I mean bends and elbows which was the original question.

I know, I used to do this a lot a few years ago, I used to carry out a lot of installation work on new large supermarket stores, we used to create a loop in the pipes, which used to be a pain when you are using 35mm and 42mm, so we changed and used the bellows and yes we used to anchor at the correct points.

 

[wilhelm]

D.i.a.

Never say

 

[doitall]

D.i.a.

Never say

My favorite actor this week

However I will repeat it for a third time.

Never, never, ever, use bends or elbows as an expansion loop or whatever you want to call it.

 

[wilhelm]

check

the opening statements on it, still apply today

 

[wavetrain]

I now see what you mean about the pulled bends.

In the case I am looking at, the CH installation is complete, it works but there are some areas of concern and my role is to make my client aware of them on a goodwill basis. So regarding these offsets, we know they shouldn't have been done this way and I would not do something like that in my home and sleep soundly, but are they likely to break down in the future?

The measured expansion was 2mm on a 135mm offset on 22mm pipe.

I can envisage my client getting another heating engineer to make a report, would he also consider they were at high risk of failure or would he think I was just a scare monger?

 

[ChrisR]

Can you draw what you mean - it's not clear where you're measuring the 2mm in relation to the offset..
Is the offset made with endfeed elbows ?