Leaking CH pipe - Compression and push-fit mismatch?

[russellpeters]

Dear Forum members,

For about 3 weeks now there has been steady loss of water pressure in the central heating system in my house. Simultaneously multiple damp patches formed on the ceiling in the living room.

The first patch was in the shape of a crude circle right under where a first floor radiator is. The remaining 2 patches were narrow lines about 100 cm long and 2 cm wide. These 2 patches were quite some distance (about 150 cm and 300 cm away) from the first circular damp patch

Putting two and two together I cut out a small section of the ceiling plasterboard (is that the right term?) under the radiator after draining the CH system. I discovered a elbow joint that seemed to be leaking and I confirmed this by putting some water back in the CH system.

I have attached some photos that show the situation.

I need help on the following questions:
(a) What is the best way to fix this leak? I want to do it once and do it properly.
(b) Is there a fitting type mismatch between the pipe and the elbow joint used?
(c) Why are there 2 long narrow patches a few meters away from the leak? Is it likely that water flowed into the ceiling void and just happened to accumulate where there was a depression?
(d) There seems to be fungal growth in the ceiling void? How do I remove this fungal growth?

Any help and suggestions would be much appreciated. Thank you.

Hole in ceiling

• russellpeters
• 20 Jan 2014
• 1

Ceiling void

• russellpeters
• 20 Jan 2014
• 1

Leaking CH pipe

• russellpeters
• 20 Jan 2014
• 1

Leaking CH pipe

• russellpeters
• 20 Jan 2014
• 1

Long narrow damp patch

• russellpeters
• 20 Jan 2014
• 1

 

[ScottishGasMan]

Theres nothing technically wrong with using a compression fitting as seen with most plastic pipes, however I would drain and remove fitting to check that there is an insert in the end of the pipe which gives it the strangth to take a fitting on it, (google plastic pipe inserts)

The long damp mark will more than likley be where the water has flowed till its hit a joist in the ceiling, moved along it and seeped through along the length of the joist.

Moving forward, if the plastic pipe has an insert, and all is undamaged, you could just wrap/paste the olive on the pipe and tighten it all back up.

Personally, while the ceilings out, Id remove fitting and copper going to rad valve and renew both to give the best chance of keeping it problem free.

 

[Blagard]

While you are dealing with that leak, there is an electric cable that "appears" to be bent around the central heating pipe. - It may be it is not as photo's can sometimes show an illusion, but if it is, you need to clip the cable out of the way to get a couple of inches clearance.

 

[Armo74]

I would also try and position the joint a little better to take a bit of the strain off it that it looks like it has in the picture with the bend in the plastic pipe if you can.

 

[russellpeters]

ScottishGasMan, Blagard, Armo74 - thanks for all the words of advice.

I am going to drain the system, take out the elbow joint and proceed depending on what I find. I will keep you posted.

 

[russellpeters]

For "plumber's paste", will one of these do?

FloPlast Lubricant Gel 800g - http://www.screwfix.com/p/floplast-lubricant-gel-800g/10631
FloPlast Silicone Spray 400ml - http://www.screwfix.com/p/floplast-silicone-spray-400ml/13662

 

[Charnwood]

For "plumber's paste", will one of these do?

No. Boss White or Hawk White (for non-potable water). Sealing compounds.
Or PTFE tap.

 

[russellpeters]

I have good news and bad news.

Good news is that I opened up the nut, removed the olive and found that the plastic pipe did not have an insert. I put a new insert, a new olive and attached the pipe back to the elbow joint.

The bad news is that I did not use plumber's paste or PTFE tape. I used lubricant gel that I mentioned in my previous post.

For now the leak seems to be fixed. The CH system has been running for about the hour and there are no signs of a leak.

Should I detach the pipe, apply plumber's paste and put it back together? Or is what I did good enough?

Thanks.

 

[Armo74]

No leak, no need to do anything in my opinion.
Just keep an eye on it for a bit.

 

[Charnwood]

Not sure what made you think silicone lubricant would seal a compression joint.

 

[Norcon]

Lubricant gives you a tighter joint for less torque.

Same as tightening a wheel nut.
Some argue that lubricant is not necessary. Usually the ones using high powered air wrenches.

Then eventually the threads are damaged and new studs needed or corrosion seizes the surfaces.

 

[Dean744PiN5]

What was that you was saying a few weeks ago nobcon about compression being better underfloors than pfit fittings

 

[Norcon]

If it was pushfit it would have been blown off months ago silly boy.

 

[Dean744PiN5]

 

[xr4x4]

By the look of the mould under there, it's been leaking a LONG time.