In article .com,
kiich wrote:
By which programmer though? the programmer underneath the boiler OR the
7 day immersion heater one? or both?

The boiler programmer (CH & HW).

kiichi ok - so if the boiler programmer controls the valve, what
exactly is the "7 day immersion heater timer programmer" used for?
to heat up the cylinder??

Normally, only if the gas central heating fails.

so if my understanding is correct,

1) the boiler programmer controls when the BOILER should come on for
both HW and CH and also the valve to let water cycle through from the
hot water cylinder to the house for CH

It switches on the boiler if there is a demand. The thermostats in the
room and on the tank control the actuation of the three way valve.

2) the 7 day immersion heater timer controls when to heat up water in
the cylinder tank - so that the water in there can be used to heat up
the CH

No. An immersion only heats the hot water - not the CH.

so from above, am i right in thinking that both timers settings needs
to be the same?? why not have just 1 controller to do both??

Because the immersion is only a standby in case the boiler is out of
action.
And it only heats the water.

--
*When cheese gets it's picture taken, what does it say?

Dave Plowman London SW
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