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. (Posted this in the incorrect forum before - sorry)

 

[petit_pablo]

Put a sandwich bag over the relief valve outside for 24hrs. Theres a good chance the expansion vessel is flat and requires recharging. See the forum FAQs. The problem will get worse the longer and hotter the CH is on for.