On Wednesday, 1 May 2019 23:52:19 UTC+1, T i m wrote:
On Wed, 1 May 2019 11:38:44 -0700 (PDT), tabbypurr wrote:

[1] I think you can only officially buy the head, or head+body
(complete solution), not the valve body on it's own.

I've just been dealing with the same mymptom caused by the ball-stem seizing, a common mode of failure.

Not the case in this case I'm afraid, the shaft is 'finger turnable'
and even when turned firmly to HW only, you still get CH.

Well if you're getting outputs from both ports, the motor is moving to halfway and stalling as it should. Which leads me to question if the valve is actually the problem. Have you monitord its electrical lines?

You can replace any faulty part of it, including the ball-plate.

Whist I couldn't imagine the valves being assembled with 'matched'
actuator arms / ball-valves, I thought I'd ask here first.

The base (Below the ball plate) is not subject to wear.

Understood. I was concerned if it could simply be a piece of limescale
that could be impinging across the face of the CH outlet.

easy enough to scrape it, but assuming it's a vaguely modern primary the water seldom changes, so no limescale opportunity.


Beware of used parts.

I would only go new on this sort of thing.

I saw base sections new on ebay for about Ł22. Obviously you need to know what's faulty first.-

Well, other than it's difficult to go much further without examining
the insides of the valve?

*If* the valve actuator arm, ball and mounting plate should be
interchangeable between all such valves (Make / model etc) then I'll

very unlikely

first get one, then drain the system and examine the valve by removing
the side plate. If it's that (damaged ball and I don't know what else
it could be), then I could first swap the backplate and if there is
some compatibility issue, put the complete new valve body on (that I
can test for leaks before fitting etc).

Cheers, T i m

It could be an electrical issue. They also suffer from swollen balls sometimes. I can only hope that's not your problem.


NT