On Sun, 17 Oct 2004 12:18:53 +0100, "Set Square"
wrote:


From what I've read about Combis, it sounds like a classic case of diverter
valve failure.

For all I know, you could be right. I'm just wondering though, that it
might be that the pressure at the taps isn't enough to trigger the
diverter valve or switch the pressure switch. I'm thinking of taking
the secondary heat exchanger out to give it a descale. The flow is
definitely impeded a bit.

Can I take the secondary heat exchanger out without draining the
system? I tried isolating the boiler, but as soon as I started
unscrewing the secontary heat exchanger, water started spraying out at
fairly high pressure, so I tughtened it up again, fast!

I'm still wondering what might be causing all the air in the DHW
pipes, which splutters out at the hot taps. Surely that must be a
strong indication of something or other, yes?

Dave L