Humming and swashling noises from pipes in airing cupboard!

[Emily34]

Hey, sorry no nothing about plumbing other than I've just had a new diverter valve fitted which is great, but I get a constant humming and swashling kind of sound from the pipes lnked to this.
I tried turing the pump down which resolved the noises, but had to turn it back up as the radiators weren't getting hot downstairs.
Is there any simple fix that can be done to avoid a call out?

Emily

 

[mredd]

It sounds like a lot of air is in the system. Call the plumber back as he needs to bleed the system.