Two problems in one here.
1. I had a new pump put on a while back by Ideal engineer. Not sure of the quality of their branded pumps. It just sounds like flushing water through it when it runs. He came back and said it might be the vertical distance between pump and F&E tank which is about 1.12m, however it didnt do that for years before pump was changed. Correct 450mm distance between vent pipe and water level in tank.
2. Decided to clean F&E tank as it needed it. Emptied and cleaned by hand and then drained off some of the system. Applied Sentinel x400 and filled tank. Bled all rads. Started up with boiler stat down to run pump cold. Checked bleed valves again. Ran on hot for two hours and bled again, but two downstairs rads were cold. One horizontal rad and one vertical, top fed rad. The other Horizontal rads are fine in that room and the other identical vertical rad either side of doorway is fine too. Not sure if this is air locks or how to remove them. Water was actually quite clear when drained down and have a Magnaclean in system.
Any help appreciated.
