How to fix loud gurgling /rushing sound in system

[ElCI]

Hi all, I'm hoping someone can point me in the right direction to fix an issue with my heating system .

A few days ago I had some maintenance done on the system (drained down, cleanser put in and later removed and rads jet washed out to clean sludge ) . Since then I have noticed a very loud gurgling /water rushing sound . This seems to be coming from the cylinder and seems to happen once the boiler has stopped . Even though the boiler has stopped the external pump seems to still be running , the noise continues until the pump stops . The noise is very very loud, I will try and record on later if it helps . I have done a quick Google search and it seems it may be air in the system , would this make sense? I know there are 2 bleed points on a vertical pipe next to the cylinder so I could try and open these until water comes out but thought I'd better take some advice on it 1st , can anybody advise on this please ?

Thanks in advance for any help

 

[oilboffin]

It's air finding it's way to the highest point in your system so try to bleed it out or get the plumber back to finish what he started.

 

[ElCI]

Thanks , that's what I suspected . If it's an easy fix I'll do it myself , I expect the highest point will be these bleed points next to the cylinder . Am in able to bleed it at any time or should I wait until the noise is happening before I do it . Also, is likely to be causing any problems or danger to the system or is it more just a noise nuisance ?

Thanks again for the quick reply

 

[oilboffin]

Do it with the heating off so the system is at rest.Bob

 

[ElCI]

Cheers Bob, I did it earlier , a fair bit of air came out of the last few radiators I did so hopefully it'll fix the issue !
Thanks

 

[slippyr4]

If your system is pressurised rather than open vented (i.e. You have a filling loop with a small pressure gauge, instead of a small tank in the loft) then you may well need to top up a little bit more water after bleeding.

 

[ElCI]

It's an open vented system , I have a cold water tank and F&E tank in the loft so from my limited knowledge I think this means it'll top itself up?

 

[slippyr4]

Correct