After running ds40 through my system because of some annoying kettling now gone 
I now have an aeroplane sound from around the top of the boiler, this seems to kick in after about 10 mins of the CH firing up. If i run the pump at its lowest speed the sound is miniaml but rads take alot longer to heat up. If I raise the speed on the pump it gets unbearable.
Once the boiler switches off and the pump overun kicks in the sound dissapears. I have tested this on all speeds with the same result.
I now have an aeroplane sound from around the top of the boiler, this seems to kick in after about 10 mins of the CH firing up. If i run the pump at its lowest speed the sound is miniaml but rads take alot longer to heat up. If I raise the speed on the pump it gets unbearable. Once the boiler switches off and the pump overun kicks in the sound dissapears. I have tested this on all speeds with the same result.
