"Rushing Water" Sound in Radiators

[Ninja_1980]

Evening all

I’ve just moved into a new house with a Baxi 105e combi boiler.

Everytime the central heating is switched on I can hear a reasonably loud “rushing water” sound from the radiators.

I friend of mine thinks it could be air in the system. I have bled all the radiators and the sound still remains. Also, the only automatic air vent in the system are in the boiler.

Any advice would be gratefully received

 

[JohnD]

did you get any gas out?

Did you do it with the boiler turned off?

If you do it again, 2 days later, is there any gas?

What colour was the water?

Does it make any difference if the valves at both ends of the rad are fully opened (just try on one, and count the number of turns so you can put them back where they were after the test)

 

[Ninja_1980]

Thanks….

1) Only got gas out of the 1st floor rads
2) The boiler was turned off
3) There was more gas (just bleed the top rads just now)
4) The water was clear
5) I’ve just given the lock shield valve a few turns on the 1st radiator and the system is virtually silent

Thanks for you help. I’ll just have to have a go at re-balancing the system later 2day.

Also, the air in the system could be because I had to top up the pressure a few days ago (oxygen from the fresh water) because the boiler doesn’t seem to be able to maintain pressure (I’ll post a new thread on this now). I’ll try bleeding the rads again in a day or 2. If there is still air coming out, what do I have to look for?????

Thanks again