On 13/11/2017 15:59, T i m wrote:
On Mon, 13 Nov 2017 14:23:56 +0000, John Rumm
wrote:

On 12/11/2017 15:15, Johnny B Good wrote:
snip

It doesn't (or shouldn't) stay in the latched position once the system
is powered up and running. I can't say whether this also applies to the
two port valves since I only have experience of the 35 yo single 3 port
diverter valve (Y or S plan ?) setup used here.

Yup two port ones have a similar feature (or at least the Honeywell ones do)

So that's 'the two port ones *can* have a similar feature ...' as
that is my question ... are we assured that all makes and models do?

Not having seen all of them, I can't answer.

The point was that if someone was expecting some form of manual
control and thought they saw one, but it didn't move, does that alone
guarantee that the valve was faulty / stuck, or could there be some
valves that simply couldn't be overridden manually or can only be
overridden in one direction or some other conditions(s) etc?

I would expect that of someone was suggesting the valve were "stuck",
they would not be talking about the manual leaver. In these situations
is more common to take the motor head right off, and see if the spindle
sticking out of the top of the wet bit will turn (with pliers and
lubrication etc). If its seized, then replacement of the wet part
becomes necessary.

I'm not expecting a definitive answer from anyone in particular, just
putting the question out there as a definitive answer may suggest my
friend is being 'duped' by the plumber ... ;-(


--
Cheers,

John.

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