if you draw off a mug of water from the drain cock, is it deep black?
have you noticed any improvement in the radiators?
did you adjust the ball valve in your F&E tank so that the water level is only a couple of inches above the outlet pipe near the bottom?
How muddy was the F&E tank? was there any sign of drowned wildlife when you bailed it out?
p.s. another cause is incorrect piping round the pump. Can you post some pics of the pipes? there should be a 15mm feed pipe, and the 22mm vent pipe, joining onto the main circulation pipes near the pump or cylinder. the layout of these may have an effect.
have you noticed any improvement in the radiators?
did you adjust the ball valve in your F&E tank so that the water level is only a couple of inches above the outlet pipe near the bottom?
How muddy was the F&E tank? was there any sign of drowned wildlife when you bailed it out?
p.s. another cause is incorrect piping round the pump. Can you post some pics of the pipes? there should be a 15mm feed pipe, and the 22mm vent pipe, joining onto the main circulation pipes near the pump or cylinder. the layout of these may have an effect.
