Vaillant EcoTEC Plus 624

[DavidCo]

Hi I wondered if any body can help - I have one of the above boilers fitted (by a Corgi registerd plumber about 3.5 year ago). It's being used for domestic purposes with 13 radiators running from it. I've had problems with it losing pressure for 24 months plus. The plumber who fitted it has visited but can't find any leaks and doesn't know what's wrong. We checked the pipe which leads from the boiler outside (presume some sort of outlet from a safety valve and there doesn't appear to be any water coming out of there). The loss of pressure is inconsistent sometimes it will go for a couple of weeks without having to 'top it up' and other times (like now) I'm having to 'top it up' daily (don't know if this has any relevance but the pump was replaced about 11 months ago - it got noisy and started to leak).

Any advice gratefully received.

 

[stem]

This post would get a better response in the 'Plumbing' section, rather than 'Roofing & Guttering'. You could ask the mods to move it for you.

If you are loosing pressure, and keep having to top it up there's a leak somewhere. They can be hard to find.

For example, I had a radiator in a cabinet that was leaking at the top from a gasket around the bleed valve that had perished as had the gasket around the blank at the opposite end, When the radiator was hot, the leak kept evaporating it so that it wasn't obvious, when the radiator was cold it dripped onto the carpet inside the cabinet where it evaporated later when the radiator came back on. Judging by the mess, it had been leaking for a long time when I eventually found it.

It's not an ideal solution but I have known a proprietary sealant added to the water used with good success.

Is your Vaillant a combi? or is there a hot water cylinder connected to it? If there's a hot water cylinder, it has been known for he internal coil to leak water from the heating/boiler circuit into the cylinder where it is mixed with the domestic hot water.