Mid Position Valve has to be frequently replaced

[GlennI]

Hello

Since moving into my property in 2016, I must have been through 5 or 6 mid position valves of various makes. I am just about to swap over the current Drayton MA1 which was installed 8 months ago because it now has the same fault as all the previous ones. The fault is that sometimes (not all the time) when the heating is being called at the same time hot water is being called, when the heating gets to temperature and the room thermostat stops calling, the heating remains on with the boiler firing away. The only way to stop the heating is to switch the hot water off at the programmer.

When the valve is replaced can go for a few months working fine, then it happens again. Until now both head and valve have been replaced and I'm about to change just the head (to try and save on calling a plumber out for re-occurring fault)

My only thoughts would be the wiring, but it doesn't have the fault all the time and on all previous occasions my plumber has swapped over the part so assume he has checked all that!

Any suggestions would be most helpful

Many thanks

Glenn

 

[ShaunCorbs]

3 ports are cr-p best to replace for 2 2 ports

 

[Deleted member 120897]

Could always use one of these for the wiring? Are you sure it’s the valve? Seems a lot of replacements.

 

[GlennI]

3 ports are cr-p best to replace for 2 2 ports

Ok I'll mention to my plumber

 

[GlennI]

Could always use one of these for the wiring? Are you sure it’s the valve? Seems a lot of replacements.

I don't know what else it could be as once replaced works fine for a while and even then it is intermittent. Good idea about the connection seems as it gets replaced that often!

 

[Knappers]

Dodgy contacts on old programmers or cylinder stats can cause issues so worth checking those?