...much clearer now.
Combis seem a pretty useless design... seems guaranteed to fail...
can't say I'm clear how best to stop the problem re-occuring...
shelling out £600 - £800 per year to have the system flushed doesn't appeal... but what other choice is there...
will making the...
OK, so the symptom (loud banging) is a result of restricted flow through the (clogged up?) heat exchanger... that makes sense.
Short term solution = change heat exchanger...
However the damage to the exchanger which is resulting in a restricted flow must be being caused by something...
Problem is with a Worcester Bosch 28CDi installed 2 years ago.
System runs without problem for the central heating but (whether the heating is on or off) the boiler makes alarming noises when the hot taps are turned on... it's done this for the last eleven months becoming progressively...