Weird problem with 3-port valve - affecting CH

[gigz]

Turn it with your fingers, if its ok it'll turn easy (only goes a short way, not right round).

 

[gazdaz36]

It the programmer/room stat isn't calling for heat then there should be no voltage on the white wire to the 3 port valve so should not fire the boiler. Generally 3 port valves will stay in the ch only position when the the last demand was for ch only and will only spring back once the voltage has gone from the hot water off wire. You need a multimeter and someone who knows what to test

 

[DavidFox]

Turn it with your fingers, if its ok it'll turn easy (only goes a short way, not right round).

Thanks. I believe I can remove the head and test. However, is it easier to put the head back? I am not a plumber and won't take risk not having the CH in the current weather -

 

[DavidFox]

It the programmer/room stat isn't calling for heat then there should be no voltage on the white wire to the 3 port valve so should not fire the boiler. Generally 3 port valves will stay in the ch only position when the the last demand was for ch only and will only spring back once the voltage has gone from the hot water off wire. You need a multimeter and someone who knows what to test

Thanks. I have a multimeter and some electricity knowledge.

However, in my case, when my CH is off (through programmer) after 10pm, the lever always stays in the 'Auto' end (firmly, strong resistance to move to the 'MAN' end, as mentioned in my first message). It seems back to somewhere in the middle in the morning after CH is on. Is this phenomena right?