Tracking down a central heating system leak

sundin13

Hi, our Worcester Combi boiler/central heating system has been losing pressure for the past few months, and requiring topping up with water quite regularly.

I had a heating engineer come round and he put some stuff into the system which was supposed to seal leaks, and it probably did have some effect for a while, but now its worse than ever. It takes about two days to drop from fully topped up (about 1.5 bar?) to 0 on the pressure gauge.

Assuming this means that there is a leak somewhere, how do you go about finding it. None of our radiators have any visible signs of leaks, so I can only assume it to be a pipe somewhere. Trouble is, our whole ground floor has laminate flooring, so I'm horrified by the thought it might be a leak under there - as it would mean pulling up the laminate to investigate.

I just wanted to know if that was what would have to happen? Is there any other way to work out where a leak is coming from? Your thoughts and advice would be much appreciated.

S13

Canucklehead

Good afternoon: Are you confident the pressure problem isn't boiler related? See more here. To find who is the culprit you will need to isolate the boiler with minimum 1 bar pressure in the system for at least 12 hours (this means the boiler will be 'offline') If the pressure drops it is the boiler and if it doesn't then open the valves under the boiler...if pressure drops in this instance then it is the system at fault...either way you'll be spending out;)

HTH

Canucklehead

robv_3

To narrow it down further you could put isolation valves in the ground floor feed and returns.

If it turns out to be under the floor get a thermal imaging company in to see if they can find it. A little hit and miss and miss and miss.

See if your house insurance will cover seek and uncover.

sundin13

Canucklehead wrote: »

...either way you'll be spending out;)

That's what I was dreading!

Thanks guys...I shall bite the bullet and get the engineer back out. At least I'll know what he's talking about now.

S13

Canucklehead

andrew-b wrote: »

But surely if the heating engineer who chucked in leak sealer was worth his salt he should have tested if it was boiler related in the first place? Or is it standard practice to try fix it with leak sealer before getting the tools out the van? Or is this heating engineer not worth his salt?

Andy

Good evening: As has been said before, being GSR is no guarantee of competence: recommendation via a source you trust is the best route to finding a tradesperson (and advice given by anoymous parties on an internet forum can often be spurious or dangerous hence the warning posted at the top of the forum).
Using leak sealer on a central heating system is a road the OH would never go down. Viessmann, for example, considers the use of CH leak sealer and Boiler noise silencer (as well as other non-approved additives) as grounds for invalidation of the warranty.:eek:

The OP needs another RGI to diagnose and repair the fault(s).

HTH

Canucklehead

ariba10

We had a problem with a Worcester boiler losing pressure with no apparent leaks.

It was resolved when the pressure vessel was re primed with compressed air.

Apparently the lack of air had caused the water in the system to vent through the overflow/vent pipe.

looby-loo_2

We have this same problem. Our installer told us we must have the heating off for two weeks to test to see where the leek is. Is this normal as above it says 12 hours? Or does it depend on the time it takes to loose pressure? Out system takes 10 day between repressurising.

Also, will the hot water need to be off too whlst testing?

Thank you

Canucklehead

ariba10 wrote: »

We had a problem with a Worcester boiler losing pressure with no apparent leaks.

It was resolved when the pressure vessel was re primed with compressed air.

Apparently the lack of air had caused the water in the system to vent through the overflow/vent pipe.

Hi...perhaps the OP will let us know the prognosis....hopefully it is the moneysaving option.;)

Canucklehead

Canucklehead

looby-loo wrote: »

We have this same problem. Our installer told us we must have the heating off for two weeks to test to see where the leek is. Is this normal as above it says 12 hours? Or does it depend on the time it takes to loose pressure? Out system takes 10 day between repressurising.

Also, will the hot water need to be off too whlst testing?

Thank you

Hi...12 hours is enough time to eliminate a boiler fault and will point the finger at the culprit i.e. pipework, radiators and rad valves. The boiler will be offline during the testing period therefore no heat (and no hot water if you have a combi or don't have an immersion heater). The CH system can also be pressure tested using one of these .

HTH

Canucklehead

sundin13

Canucklehead wrote: »

Hi...perhaps the OP will let us know the prognosis....hopefully it is the moneysaving option.;)

Canucklehead

I certainly will...I won't be able to do anything about it in the next couple of weeks though - so I'll wake the thread up when I do.

And further to the comments, I think I might try a different heating engineer too. I was sticking with the same guy as our boiler is, to be quite honest, a bit of a lemon, and he knows the history. But who knows - he could be part of the problem.

Thanks all.

S13

swervo

My boiler (also a Worcester and probably around 11 years old now) is showing similar symptoms.

I'd love to know how this worked out for you.