noise from wb cdi30 when central heating on

[hitlo2002]

i'm hoping someone here can help me!
have just had very old conventional boiler with hot water and cold water storage tanks removed and replaced with new WB CDi30 combi. have had all 5 radiators replaced, 3 with TRV's. i am having a very irritating humming sound that runs through all the pipework and all the radiators in every room when the central heating is on, sufficiently loud to wake us up/stop from getting to sleep. everywhere i read it says the pump is too high and i should turn it down; this particular boiler has 'an automatic pump' with no manual override so far as i can tell - can anyone please advise me on what to do?! its driving me nuts!
all help appreciated!

 

[tamz]

Do you only have 5 rads on the system?

 

[hitlo2002]

Yes only 5 rads, only 1 bathroom

 

[hitlo2002]

Also if it helps I noticed the noise start immediately after an automatic bypass valve was fitted. Have tried playing with it but to no avail!