worcester 24i rsf-cant bleed

[chrislione]

i replaced the prv as it was letting by, recharged the pressure to 1.5, and turned back on, after 20-30 seconds i could hear "gurgling" then a dull knocking, sounds like air in system, bled all rads(all fine)took cap off pumphead and that was turning ok. noise does stop when i turn on hot tap but returns a few seconds after turning off. its an old boiler and does not have(that i can see) the auto air vent,though it does have a small tube sticking out the top next to the reset button with a "washing up liquid bottle top" cap. any suggestions are v welcome

 

[Agile]

Apart from the noise, is it firing up and giving hot water and heating?

Tony

 

[chrislione]

fires up first time, good heat but reluctent to leave on too long as it starts to make quite a rattle, thanks
forgot to say needle on the pressure dial bounces around. but does not gain/loose when off.

 

[bobthebender]

The AAV is on the top of this boiler...as i remember ?