The bleed screws are those little square ones at the back (not side) of each radiator so when they squirt out they hit the wallpaper.
The property is a bungalow so all radiators at ground level but the pipes go up and over via the attic.
Anyhow most of the radiators instantly let out a silent stream of water.
A couple sputter, water comes out but with a sputtering sound and/or a whistling sound and this is where I'm confused. It seems no matter how much I let out (I'm talking cup fulls not gallons) they still seem to sputter. They sputtered yesterday, today and I expect they will tomorrow.
Is this air in the system or is it just the shape of the screw?
Am I correct in assuming that air cannot be introduced into the system unless there is serious corrosion or the like going on?
How much oxygen am I reintroducing repressurising the system?