Is there a plumbers trick for working out what is in a pipe?

[olfrog]

Hi all!

Done the course now trying to replace bathroom.

However, have found a mystery 15mm copper pipe that goes from kitchen via bathroom and into loft. It has nothing coming off it (no taps etc) and i cannot access the other end of it in the loft (which disappears into a 22mm pipe). It's about 10m and has boxing out around it (so would be nice to get rid of). I have a feeling it's from some old system..

Is there a plumbers trick to work out what is in a pipe? (Could it be gas from an old kitchen, or is it mains, or is it from the previous indirect system?)

Thanks,

Ol

[Rodreguez]

could be anything but sounds like a mains pipe or maybe gas.

[fuzzy]

absolutely no idea, it can be hard to correctly identify, if it was essential you could find an appropiate place to cut it, turn off water gas heating, drain down, cu in, slowly fill and see if anything comes out, is it worth it?

[azza100]

the 22mm pipe could be a sleeve and it could be mains to the tank? or an old tank that used to be there

[tackleburger]

The plumber's trick is experience and know how. If you trace a pipe to identify you can normally work it out. If you can't leave it as you find it and never take a clients word for it. I got a call about three months ago because a joiner cut a capped lead pipe away as the client said it was dead for sure. And of course it wasn't.

[franky]

You might be able to tell if its mains if you ran the ball valve in the tank it should be a lot colder, also any compression joints along the line?

[WHPES]

To elaborate on the previous post, if there are any compression joints you could crack one open slightly and see if anything comes out.

[REDSAW]

if you cut into the pipe and it is wet, it will be water.
if it smells, it could be gas.
but i may be wrong?

[smallyfish]

cut into the pipe?,the pipe would be broken,that 's not a good way.

[franz]

you dont say where it starts in the kitchen. ?

[olfrog]

Thanks guys!

Well, i couldn't wait so yesterday before i got a reply i turned off everything and sliced the pipe. Turned water on, nothing coming, turned gas on, whoosh! So, it's gas.

I cut back the pipe into the loft, then wire-woolled the end and covered everything in boss white. Stuck a compression stopend on and tested it 3 times with some washing up liquid to see if there were any bubbles. Touch wood all seems fine!

The strange thing is the amount of gas pipe work in the loft - maybe originally it had gas fires everywhere as it has pipes going everywhere.

Ol

[REDSAW]

washing up liquid eh!.
classic.

[WHPES]

If you aren't 100% sure if you have drained the right pipe (EXCEPT if there may be a gas pipe there), have a self tapping screw handy, drill a hole in the pipe before you go at it with the pipe slice, and if water pors out, drive a self tapper into the hole wrapped with PTFE tape as a temporary plug.