There is a small copper pipe that will go through the wall to outside somewhere near the boiler see if that is dripping. It is not impossible for the boiler to be leaking internally, but there are more likely places for leaks to occur.
Remember you have a sealed system, and only a very small leak will cause the pressure to drop. Probably a mug full is sufficient so if the leak is slow, most of the water will evaporate and leave little trace.
Check radiator valves and the carpet or flooring where water might drip. Then examine closely any exposed pipework and joints.
You cold try a leak sealer, but I would exhaust every other route first.
if u have noticed the boiler leaking to outside, then the pressure relief valve is passing and needs replacing, it could also be the charge of the pressure vessel which will allow the pressure to rise above recommended pressure 3bar when the boiler is in use, hope this helps
Thanks adam I've just re-pressurised the system to 2 bar and without anything turning on I noticed the water coming out of the outside pipe.also the pressure has gone down...not surprisingly I suppose?????
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