Colin Chaplin wrote:
Hi All

I've got a problem with my central heating/ hot water.

It's a setup that I imagine is fairly common to newish houses, gas boiler in
the kitchen and thermal store upstairs (well - it was moved in to the loft a
few months ago)

I can hear water running through the system constantly -24x7- and I am at
somewhat of a loss. I've just turned down the speed of the pumps which has
quietened it down but I think that's just masking it?

The central heating side of it is turned off. The boiler fires every 23 mins
or so then goes for a few minutes before shutting down , I assume to keep
the water hot.

A quick googles suggest something about excess hot water being pumped
through the radiators.

Everything else appears OK. When the system was moved, it was 'simply' a
case of cutting pipes and extending them to fit the new position in the
loft. I was prepared perhaps for a little extra noise when system is on, but
not this.. could this have any bearing on it?

Any clues people?

You need to do a check list...

Does is happen if you turn off the HW on the programmer?
Do any of your radiators get hot when the boiler keeps firing for the
CH?
Get someone to turn off the HW and see if the motorized zone valve
operates.
Do the above for the CH.

If you've had things moved, then it may be a wiring problem, if that
was tampered with.
Also, system components can pack up if they are disturbed after
months/years of use.

Check the Cylinder Stat, any MCVs and the programmer.

Something is telling the HW to keep circulating through the system. The
way this works is that the Cylinder Stat tells the programmer if the
water in the cylinder needs heating, if the programmer is in HW "on"
mode, then an MCV directs water through the cylinder, the pump starts
and the boiler ignites (at roughly the same time with a number of
checks performed). Thus, the new 'circuit' transfers water from boiler
to cylinder (in a loop) where thermal exchange heats the water in the
cylinder.

Is your water (from your taps) very hot?
I'd be looking at the Cylinder stat first, then the MCV(s) then the
programmer.

Hope this helps you.

rgds,
deano.