Leak sealer and microbore piping

MarcoC · 24 Feb 2006

I have a sealed CH system and at the moment it seems to be losing pressure at the rate of about 0.5 bar per week. There are no visible signs of leaks and British Gas, who we have a service contract with, want to put leak sealer in the system to see if it stops the pressure drop.

My question is - we have microbore pipework and a friend of ours who is a plumber said that you have to be careful with leak sealer and microbore as it can clog up the pipes. Does anyone know whether it's Ok to use leak liquid leak sealant with microbore piping? If it isn't, what other options do we have?

Marco

Agile · 24 Feb 2006

There is no answer to that question!

If the microbore is not sludged up and has no restrictions then there should be no problems.

The risk of partial blockages is high and I would not do that myself ( except at home but then I would be replacing with normal tube! )

Tony

MarcoC · 24 Feb 2006

Thanks, but if we don't use leak sealer then how exactly do we track down a leak that could be absolutely anywhere?

Agile said:
There is no answer to that question!

If the microbore is not sludged up and has no restrictions then there should be no problems.

The risk of partial blockages is high and I would not do that myself ( except at home but then I would be replacing with normal tube! )

Tony

JPC · 24 Feb 2006

if u leave it to bg to do their stuff and it becomes blocked, i take it they have to sort it anyway ? or not ?

MarcoC · 24 Feb 2006

Yes, they have to sort it, but at the end of the day because you get a different engineer each time, they don't always care much about the longer-term implications of what they do. My experience is that if they can do a quick fix they often prefer to do that...

My question still stands - are there any ways of detecting where a leak might be? ...other than knccking holes everywhere!

JPC said:
if u leave it to bg to do their stuff and it becomes blocked, i take it they have to sort it anyway ? or not ?

ChrisR · 24 Feb 2006

It's often weeping rad valves. Are your pipes buried in concrete? Can you get to the manifold(s)? At least you know there aren't loads of joints.

Has the pressure vessel precharge been set recently? If there's almost no air left, any small water loss shows much more.
What boiler is it, and have you checked the auto ait vent is bone dry as well as the pressure relief pipe which goes through the wall? BG should have done, but none is hard to do.

MarcoC · 24 Feb 2006

We HAD some leaking rad valves but they have been sorted now and the pressure is still going down. I haven't touched the pressure vessel but I have no idea what British Gas have done. It is an Ideal boiler - don't remember the model off hand but it is a current one I think - only 5 years old, and not a combi. The auto air vent is dry although the top of it (not the screw cap but the top of the vent itself, which is copper) seems partly corroded. Pressure relief valve is dry.

We have a Sadia Megaflo water cylinder and I have just noticed that there is a very small seapage of water from a pipe attached to it which is labelled 'primary flow' and which connects to a grey box marked with the brand name Honeywell. It's only a very small leak from it but might that be causing the pressure loss?

ChrisR said:
It's often weeping rad valves. Are your pipes buried in concrete? Can you get to the manifold(s)? At least you know there aren't loads of joints.

Has the pressure vessel precharge been set recently? If there's almost no air left, any small water loss shows much more.
What boiler is it, and have you checked the auto ait vent is bone dry as well as the pressure relief pipe which goes through the wall? BG should have done, but none is hard to do.

ChrisR · 24 Feb 2006

might that be causing the pressure loss?

Definitely a prime suspect. Normally that area would be hot so you wouldn't SEE a small leak, because it would evaporate quickly.
Worth having a go yourself perhaps - 1/6th of a turn say.

ACOperson · 24 Feb 2006

I have heard that leak sealer can block microbore pipework. I wouldn't expect most new gen BG guys to know this though...

ollski · 24 Feb 2006

Its as Tony says, if your microbore pipework is almost blocked the leak sealer will seal it, after all that is it's job. If your pipework is in that bad a state though it is due a flush anyway.

pierrot · 24 Feb 2006

8) Half a bar of lost pressure probably equates to about half a pint of water so the tiny leak is often very hard to find.

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Leak sealer and microbore piping

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