Humming Noise from Potterton ProMax Combi

[john2k]

When I put my CH on once it's warm I start getting a really annoying humming noise coming from the boiler. It's not a rattle but more a large hum which can be heard from most of the house even upstairs. If I press the side panel of the boiler in at the bottom with a bit of pressure the humming stops. As soon as I let go it starts again. If i pull the side panel at the bottom out a little it also stops. Any ideas what this can be and how I can fix it?

 

[Hot&Cold]

Any ideas what this can be and how I can fix it?

yes,very easy.
Ask the last company that serviced it why its now making an unusual noise.