Great, thanks for the advice. Our plumber also suggested the liquid to block the hole so will give it a go.

No sure why I can no longer edit my posts or delete the duplicate....Annabel?

[quote="calgary"]We had this problem several years ago and it took well over 2yrs to finally rectify. During that time we had two leak detection outfits come and try to find it and both turned out useless! (One checked for leaks via heat sensor and the other drained our system, pumped gas through it and then tried to locate it that way.)

I would say a first step would be to use a leak seal product that you can buy in the hardware that you put into your system. This helped reduce our leak but not get rid of it. I think for minor leaks it would work very well. Same concept as that used for old car radiators.

I finally detected the leak myself as I noticed the floorboards under the couch were becoming discoloured. That's when we ripped up the floor, laid new pipes as it was easier than trying to find the exact location of the leak (and then at least we'd know the quality was good) and then made everything good.

It was a terrible, aggravating, inconvenient, and expensive process (we also ended up needing to replace our 3-yr old combi boiler as topping it up so often had caused it to have multiple issues) so I would definitely give the £10 leak seal product a try first.

Good luck![/quote]

We had this problem several years ago and it took well over 2yrs to finally rectify. During that time we had two leak detection outfits come and try to find it and both turned out useless! (One checked for leaks via heat sensor and the other drained our system, pumped gas through it and then tried to locate it that way.)

I would say a first step would be to use a leak seal product that you can buy in the hardware that you put into your system. This helped reduce our leak but not get rid of it. I think for minor leaks it would work very well. Same concept as that used for old car radiators.

I finally detected the leak myself as I noticed the floorboards under the couch were becoming discoloured. That's when we ripped up the floor, laid new pipes as it was easier than trying to find the exact location of the leak (and then at least we'd know the quality was good) and then made everything good.

It was a terrible, aggravating, inconvenient, and expensive process (we needed to replace a 3-yr old combi boiler as topping it up so often had caused it to have multiple issues) so I would definitely give the £10 leak seal product a try first.

Good luck!

have you contacted Thames Water?
original old houses usually have a 15mm inlet from the street. most boilers/megflo's state a need for 22mm inlets. thames water will say that you should get 9 litres/minute (you test simply with a bottle at your sink). if you are not getting this then TW may have to address the problem - if its sourceable to your supply.
Thames Water may be your best contact initially, and I would think they could advise on solutions/experts.
Also - it may be worth a call to your local council environmental officer?
If you had water leaking under your basement surely you would have noticed ingress? do you have sump pumps (ie a newish basement with delta linings?).
Hope this is helpful.

Hi, we're you able to find someone to fix the problem? We are having the same issue with our boiler. Thanks

We have been advised that our low water pressure is probably caused by a pipe leaking into the ground under our basement. Rather than have someone chop bits out of all the walls to find it, I would like to use a leak detection specialist to locate the leak if possible.

Has anyone used a service like this, and if so can you recommend a specialist?

Many thanks.