teething problems folowing boiler install

[pmx_super]

Since I had a new boiler installed my central heating has been noisy and also seems to be drawing in air.

Even after bleeding the radiators it is noisy - sounding as if it has iron-fillings rushing around in it. It is possible that the power flush loosened crap up but wasn't done fully so didn't get it all out?

They also replaced my CH pump, saying it sounded like it was labouring and on its way out. The new one is the same model as before: Grundfoss Selectric 15-50, and is set to speed "2" like the old one. Might this setting be too high now the pipework is (allegedly) clear from the powerflush and since the pump is a new one, thus causing the system to suck in air?

Before I start tampering, or eventually get them back in, I'd like to understand a little more about what could be going on...

 

[simond]

It will be air and your best bet is to call back the installer.

You don't really need to know how to fix it, there are a number of causes if its an open vented system, all difficult to diagnose over the internet.

However, it could be worth checking there's some water in the CH feed and expansion tank.