I have a Worcester Boiler (Greenstar 24i Junior) which started lose more and more water starting about a 2 or 3 months ago. I also noticed water dripping from a pipe outside my flat behind the boiler. I hired an engineer from Bosch. He reported that the pump was sticking so he replaced it. He carried out a performance operation test and reported it as satisfactory. He told me he had replaced the safety valve. The dripping from the pipe has now stopped. However, I am still having to fill the boiler with at least 2 litres of water every day. The same engineer returned and told me there was no leak in the boiler, and no fault that he could find. He told me that there must be a leak somewhere in the flat and there is nothing else he can do. However, I cannot get access to the pipes as they are all fully boxed in. The flat below mine is currently been sold - the estate agents have told me that the flat is checked regularly and there is no sign of any water coming down from my flat.

Another thing I have noticed is when I am refilling the boiler when the dial is at the lowest it can go, it goes up quite quickly until it reaches the "green" part of the dial. It then goes up much slower, as if there really was some water in. Also the dial goes down very slowly to begin with. However when it reaches the red part of the dial, it seems to just drop down to zero very quickly. So it is not going down at a consistent rate. Before the engineer looked at the boiler, it was going down very quickly to begin with, then much slower the lower it got.

I am not convinced that I have a leaky pipe - the amount of water I am putting in every day would definitely have passed through to the flat below. I did not have any problems before I needed the safety valve fixing - it just seems a bit of a coincidence that I get a leak at the same time the safety valve is replaced.

Apart from having a leak are there any other reasons my boiler is losing so much water every day?

Thanks

This does seem strange. If there were a leak of that magnitude, you would think it would show itself over a period. Im sorry I won't be of much help here, just hoping you will come back and let us know what is found. Maybe try a different service company.

One thing to check is to make sure the pressure relief valve (the one he replaced) isn't still leaking. If the expansion tank is waterlogged (bad) it would cuase the pressure relief valve to pop off and very well could explain the strange gauge movements.

The pipe that was dripping behind the boiler has stopped so I think the part he replaced was done correctly. He showed me the inside of the boiler and it was completely dry everywhere.

However, a (different) plumber I have used in the past put some solution (Triple X Leak Sealer) in one of the radiators last night. The label reads it should "seal inaccessible leaks and weeping joints. Reduces pressure loss in sealed systems".

Usually by this time when I get home from work the dial is down to zero. However, it has not moved very much at all (only down a little bit) and is still well within the safe area, so it looks like my problem has been solved.

I still have no idea where the water was going though, and all the pipes are inaccessible - it would cost a lot of money to get to them.

If there are any further issues with this I will update.

Thanks

Hey, please let me know how the leak seal works out for you. Curious. Thanks.