PCPaul wrote:

Pretty much. It wasn't big, it wasn't clever and it wasn't funny ;-)

What I (the OP) *meant* was.. a combi will be firing up much more often
than a conventional boiler through the summer, every time a hot tap is
used. The CH valve inside the boiler will be constantly in a hot'n'cold
cycling environment which I would think might make it less likely to
seize? Added to which it's probably a simple two way valve not a three
way.

Anyway ISTR that this boiler cycles all it's valves and stuff briefly
every 19 hours if they haven't been used anyway, so it shouldn't be an
issue...


My conventional probably fires up a couple of times a day in the summer
- certainly at least once - when the hot water temp in the tank drops,
through usage if nothing else.

I've no idea if the valve cycles when it goes on and off HW, but if it
should seize it is out in the open under the bottom shelf in the airing
cupboard, in easy reach of an Engineer's Adjuster. And of course, it
heat cycles when the boiler goes on and off.

And it's running on a closed cycle water system full of Fernox, not raw
mains full of chalk.

So apart from the 19 hours thing, the Combi offers less accessibility,
more complexity, more power and thermal cycles, err... any more
advantages? (oh. The tank.)

Andy