In message , Hugo Nebula
writes
I'm leaving for a new job 200 miles away. I haven't yet sold my
house, so I'm going to have to leave it empty for a while. What
should I do with the central heating? It's a standard boiler fed from
a header tank, with a pump, radiators, a hot water tank and a
three-way valve.

I presume turning everything off entirely is not a good idea?

I thought of leaving the heating setting to 'On' permanently and
setting the room stat to low, just in case we get a late frost.
Should I also set the hot water to come on for a few minutes, just to
keep the three-way valve turning, and also to ensure that the boiler
does fire up at least once a day?

With the C/H running, I can't turn off the gas or electric. What
about the water?

This house was empty when we bought it, heating was off and drained
down, mains off, all water drained down.

Alternatively leave it all on, including the mains water as you suggest.
I'd probably not bother with leaving the Hot water coming on but won't
do any harm.

Check you insurance as well. Ours requires either the it all drained
down, or left on to protect against frost.
--
Chris French, Leeds