My Ariston Microgenus 27 (combi) has developed an annoying fault.
Sometimes when it goes to fire (either to heat the rads or do the DHW)
it doesn't "catch", and instead a red fault light appears and
everything remains cold. Pressing the reset button next to the red
light causes it to try again and usually (but not always) it fires the
second time round. This is particularly irritating when you're standing
naked by the shower waiting for the stream of water to warm up, and the
realisation dawns that it never will unless you go running down two
flights of stairs to press a button.
This is probably one for the engineer, but it would be useful to have
some idea of what's up before I call him out.
One other symptom which may help the experts is that whenever the
boiler does fire up, there is quite an explosive noise from the
(balanced) flue (I'm using the word explosive loosely here), in other
words there's quite a whoosh. I seem to remember reading somewhere that
this tends to happen when you have a long flue, although that doesn't
apply in my case - the boiler is on an outside wall and the flue goes
straight through it.