On Friday, 6 February 2015 18:06:11 UTC, Tricky Dicky wrote:
I had to do similar when I put in the kitchen at the last house and had no problems although I did use full flow types not the standard types which do have a slight restriction. Are you sure you have not got an air lock somewhere, I used to get them on the Micky Mouse CH system I inherited which had a lot of drop feeds to the downstairs radiators but no drain off valves on some. Due to the trapped water when refilling the system radiators would fill even vent but air locks in the pipes prevented them getting any heat..

I wonder if I've got that. I have a mickey Mouse landlord that is for surrten.