John - thanks for the re-assurance about asking Questions, it is a good
to know you dont mind helping complete DIY novice like myself

John Rumm wrote:
[...]

1) i do have a chunky manual room stat - and i cant even find it on the
sunvic website anymore. and i do hear it click as i rotate it around.

Good - the mechanics sound like they are working.


But how do I check the "clicking" mechanism part is actually telling
the programmer on the boiler to kick in CH? I have now set the settings
on the boiler programmer to be just "CH only" and to "Constant"

So I was *assuming* when I rotate the room stat to the highest it can
go i.e. 25 degrees plus, that will start the boiler up - however it
didnt and nothing is happening to the boiler.


that means it can only be:

a) the motor is buggered for the motorised valve

if so you can buy the motor part separately from the wet bit. That saves
having to mess about with plumbing if it is just the motor that has gone
titsup.
OR
b) the wiring is not telling the boiler to do CH

correct?

Yup....

or possibly the valve is very stiff and the motor is trying to turn it
but can't. (you would know that from how hard it was to turn manually).

it wasnt hard at all which makes me think the valve/spindle is ok and
not stuck.


so if i left the spindle in the position where the CH started to work,
does that mean my HW will now NOT work?
i did not see or work out what/where this "mid-position" is though on
the brass bit - is it inside the motor part?

If it is a mid position valve then it would be as the name suggests -
about half way through the rotation between one extreme and the other.
In the mid position you will get the hot water flow from the boiler
divided between the cylinder and the rads. Did you count the number of
wires connected up to the valve electronics?


Not yet - I was going to leave that till when I know for sure that it
isn't the wiring - can I say that for sure now?

I do think it has 5 wires in as the label on the motor part has a
wiring diagram and it shows 5 wires.

How can I check whether it is the motor in the motorised valve for
sure? I was expecting the motor part to at least make some
sound/vibration when I

1) Have the room stat set to highest
and
2) Have the setting on the boiler programmer for CH only

but when I do that, the motor part doesnt move/make sounds at all - i
would have thought it will try and rotate the spindle?

thanks