Another combi question, I have a Vaillant turbomax combi that has been great for the past three years but recently it shown a drop in pressure from 1.5 bar to about 1.00, despite refilling via the loop, it seems to drop back down, does this imply i have a leak in the system or is there some sort of internal balncing going on ? If I do seem to have a leak is there any other method other than visual inspection that can be used to trace a leak?
Providing it does not drop any more, it will be fine. It will read at approx 1.5 Bar when it is hot and around 1.0 Bar when it is cold ( as the hot water expands so higher reading on pressure guage ). If there is a leak then the only way to find it is to visualy inspect everywhere you can and feel where you cant. Best done when the system is cold as a small drip on hot pipes can easily evaporate and never be found and can badly burn skin.