Faulty 2 Port Valve?

[seco services]

In my mind from what I can see it really seems like the valve isn't closed but is this common with valves?

Richard

as already said if the system has crud in it or the paddle in side is breaking up.

 

[bengasman]

I don't want to drain the sytem down and replace the valve unless the odds are in my favour.

What you should do with gasprices the way they are going, is amending the system to a proper s-plan, with a decent, independent timer, a working roomstat, and cylinder stat.
And get the crap out of the system; it will be very costly to ignore that.