"Christian McArdle" wrote in message
et...
I'd expect that a faulty flow switch would simply cause it to run
cold. I don't get anywhere near 5 litres out of it before it cuts
off.

Hang on, reading again, do you mean the water stops completely? The tap is
dry?

Yes.

If so, you may have some sort of airlock. Did this start happening when
you
installed the new tap?

Nope, but it might have started when I did some other work on the
dhw pipes - that was very soon after we got the boiler in, and
I couldn't swear it did/didn't happen before that.

I installed a tee (for the shower) just below the boiler. I cut the cold
water supply to the boiler before I did this, and opened a hot tap.
Thinking about it, not much came out then either - not 5 litres worth, yet
this is supposed to be how you drain the DHW part of the boiler,
according to
http://www.glow-worm.co.uk/epower/gw...ciplus_UIS.pdf

Ben