On 04/01/2021 20:30, bert wrote:
The Honeywell Motorised valve controlling the CH is sticking in the Open
position so the heating is running continuously.
In this condition there is no resistance when moving the manual lever on
the head.

If I thump it a couple of times the valve moves and closes and switches
off the boiler/pump. If I then try to move the manual lever resistance
comes in when about half way across.

When hall thermostat switches on again the valve will work correctly and
may switch off and on a couple of times but then sticks open again.

So am I going to have yet another lesson in Sods Law or will I be lucky
and find its only the motorised head that needs replacing?
In general especially if there is hard water and not enough inhibitor
these valves get sticky. You can remove the head and access the valve
spindle and see if it turns smoothly and with little effort, without
having to dismember the plumbing. Sometimes working it a few times
manually clears a bit of blockage. Other times its is simply all gunged
up and its a whole new valve.



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