Thanks everyone, confirmed with the "engineer" last night that he switched the pump onto full speed (couldn't tell me why) so I turned it back down. I have left the system off overnight to completely cool down and will bleed and test it tonight. I couldn't find any "magnetic" blockages but that...
Thanks very much for your reply, I will set about checking the cold feed and the pump speed first.
One of the things the plumber wanted to do was change the pump. This was without seeing it running (he said "that pump looks dodgy and could contaminate your boiler" - When challenged, he...
I recently had a new boiler fitted as well as a new 2 way valve. Since starting the system, I have had to bleed one of the upstairs radiators daily.
Last night I noticed that the pump was running dry. I bled the pump and the bleed valve, as well as the radiator again.
I checked the header...