I am completely confused and need advice. I have a sealed system that must be leaking as about once a week th epressure goes to zero and the boiler thus cuts out. Now I thought I had found the leak as there was a fairly steady seapage from the join at the expansion vessel, but having fixed that the frequency of cut out has not changed! It is also (to me) a strange leak. The pressure does not seem to go down during the week but stays steady at about 1.5 when cold and 2 when hot. Its just once a week, overnight whilst the boiler is off, the pressure drops to zero, almost indicating a sudden, intermittent, but regular leak!!!
What can it be? A leak that does not affect the pressure except all at once, on about once a week?
Richard