kiich wrote:

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

Na, we can put up with Dr. Drivel here (don't ask!) - so novice
questions are no problem.

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.

It ought to (allowing for the possibility of the current room
temperature being so high as already be warmer than the maximum setting
on the stat).

If you here a click however then that suggests that it is switching.

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.

OK, so we are talking stat wiring or motor then...

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

Sounds like it is a mid position valve then...

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

It will only make a noise when it moves from one position to another.

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?

It should. But you still need to work out if the problem is the lack of
direction to do so (i.e. from the stat) or the lack of ability to carry
out the request (i.e. dead motor).

Here is where you need a multimeter on the stat. Look to see if it has a
wiring diagram. It will have a live wire in, a switched live out, and
might also have a neutral. If it has a neutral that is easy. Set your
meter to a range where it can do 240V AC, put the black probe on the
neutral, and the red on the live in. You should see 240V permanently.
Now put the red on the switched live. Depending on the position of the
stat you should see either 0V or 240V. Each time you go over the click
position you should see it change. If not, you need a new stat.

If there is no neutral, disconnect the stat completely (noting the
positions of the wires) and measure between the in an out terminals with
the meter set to a resistance range. As you go over the click position
you should see a transition from high to low (i.e almost zero)
resistance. Again if not, new stat time. If working re-attach the stat.

If that looks ok, follow the wires back to the time switch/boiler and
repeat the test there. You should see the same behaviour. If not then
suspect a wiring fault between stat and time switch.

Next look at the wires going out to the valve. (the wiring diagram on
the valve body (if there is one) will tell you which wire is which. See
if you can see a sensible behaviour there - i.e. a demand going out to
valve to move it to the CH position, If not suspect the timer/programmer.

You would also expect to see a demand out to the boiler and pump to go
with the one to the valve. The fact that you said the boiler went off in
on of your other postings would suggest that if the fault is to do with
the stat you ought to have found it by now. However I will describe the
rest of the procedure for completeness.

If ok repeat the test at the valve end. If the behaviour is not the same
then you have a wiring fault between boiler and valve. If not then
replace the valve motor.


--
Cheers,

John.

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