? valve faulty

[pandaman]

I drained my open vented ch system 3 weeks ago after having X400 going round for a month to try and sort out a partial blockage. I flushed the system out well and on advice, as the drained water was the colour of oxtail soup, put another dose of X400 in again. After filling the system I was left with a cold rad in the kitchen, did all the usual things to try and cure it with no luck. I even drained off the rad again. Water flowed ok from the inlet side but only a cupful from the return side so assumed a blockage somewhere and decided to leave any further investigations until I drained off the system again.
Today I drained just the rad again, this time water flowed from the return side but only a medium trickle. I took the rad off opened return valve again fully, again same rate of flow. Forgot to say that after emptying rad I filled it again and opened valves to see if it worked, no luck, had closed off all other rads again no luck.
With water trickling out of valve I shone a torch in the opening and to me it didn't seem to be open enough on full opening of valve nut. I think they do not look fully open anyway but this seems to be opening only a small bit. Is this a possible cause of the cold rad? I am going to drain the whole system again within the next few days so am leaving rad off.
Anyone any ideas?

 

[seco services]

if you suspect the valve is not opening change it for what they cost.

 

[pandaman]

Thanks, I was thinking of doing that as I need one with a drain off point, but could valve have been the cause of the cold rad even though it was letting some water through?

 

[seco services]

did you try shutting the other rad valves and leaving just the kitchen one open ?

 

[pandaman]

Yes tried that already, a few times, no luck.