Boiler loosing boiler pressure!

[claire26]

i have a keston c36 boiler and it is constantly loosing water pressure which i have to keep topping up once or twice a week. The water pressure drops even when the hot water is not in use.

Does this mean there is a leak? i have checked all of the radiators and pipes that i can and the plumber from keston checked inside the boiler and cant find anything! sureley if it was under the floor boards it would be leaking to the flat below?

Any help greatly appreciated!

 

[sparkfish]

Im not a plumber but the only other logical place I would check is outside where the pressure relief valve leaves the house it may be dripping there. hope that helps.