I have a problem with my Hot water, I will try to explain it as best I
can but I am new to DIY so please bear with me.

I have tried to diagnose the problem as best I can but I am totaly
stumped at what could be causing the problem.

The problem is as follows

The central heating is working (radiaters are warm) but I do not get
any hot water. In the airing cupbard there is a tank and two boxes one
with groundfos selectric on it (i think this is some kind of pump) and
another box with Honeywell F4-9348 on it and a switch which is set to
auto.

The oil boiler is working as it the pipes in the airing cupbaord are
hot.

The funny thing is that there is a switch next to the two boxes above
which if I switch it off and then switch it back on again I will get
one tank of hot water.

Also the radiaters seem to be warm even if the thermostat is set below
the temperature of the room in which it is in, I can turn the
temperature down on room thermastat and the radiaters will still stay
warm.

Everything was working fine before we went on holiday a week ago since
then I have been having these problems.

I would like to fix the problem by myself if possible and I would
appreciate any help that any one can give me, even if it is to say
that you can't help me and that I should call a heating engineer out.