Mid-Position Valve - How it works

A 3-port mid-position central heating valve has some clever electronics inside. This video takes a look, explains how it works and some of the issues that can arise.
If you're not familiar with Y-plan wiring, you may find it helpful to watch this first - • Y-plan - mid-position ...

[@pauljarrett2849]

Great explanation, thank you! Helped me find the fault.

[@beggersu]

Great tutorial Adam, thanks

[@jezlucas3878]

Best explanation I've seen thanks

[@puttingtechniques]

Great vid mate. Thanks

[@ScottRosa2008]

Thanks for this video. I have had problems with my heating working intermittently for the last few months. It will work fine for a few days or maybe a week and then the boiler won’t fire when the call for heat is made. If I turn it all off for a couple of days and then start again it will work again for a while. I assumed it was the boiler at fault nd maybe the PCB but then I noticed the hot water on its own works fine, boiler fires no problem and it works as it should. It only seems to be when CH only is selected. I can hear the boiler clicking on and off trying to start so I think it communicates with the room stat, goes to start and then the mid position actuator doesn’t move as it should.
Does this sound the likely issue to you because if it was the brass valve then the hot water wouldn’t work either? Thanks.

[@MSKChess]

2 awesome !

[@malwesterdale9481]

Great video thanks - does the synchron motor normally get hot holding the valve shut?

[@adamcarter781]

Yes and leads to premature wear in my opinion.

[@tomaszbodz1913]

Hi thanks for the wideo, When valve 3 port is set to central heating it is all the time a hot motor and there is a soft noise coming from it,
It is suppose to be like this ? How do I change to heating water everything is ok

[@carsonelias7432]

instaBlaster

[@reganobrien8262]

Hi, i was getting no movement or resistance on the spring when all power is off the switch to go from auto and manual is lose, when turn on heating or hot water nothing is moving and boiler not firing up but pump is running. I’m a gas safe plumber just looking for some advice. Thanks

[@adamcarter781]

Body spindle may be stuck, remove head, check spindle. look inside head to see if spring is broken. Boiler should fire on HW without 3PV operation, you may need to investigate this separately. Good luck.