Valiant boiler humming

[Nickclarke2183]

Hi,

So we have been doing lots of work on own house which has meant draining the system several times. So many times I'm quite well practiced and have had no issues up until now.

Suddenly when my heating is now turned on, the boiler is making a humming, almost churning like noise. Any ideas?

I have a valiant ecomax 28e.... I don't think its been fitted with a pressure gauge.

Thanks

 

[John D v2.0]

Is there enough water flow through the boiler? Is the system mucky and it's ended up lodged somewhere? And of course did you purge/bleed the system?