Vibrating/humming sounds are being produced by our ideal C30 combi.

Without seeing and hearing the problem it's difficult to answer,but based on what has been described there's a possibility that the boiler is over pressuriseing and releasing water from the system via a pressure relief valve which does create a vibrating sound, there are 3 ways this could happen but would take to long to explain, but keep an eye on the pressure gauge. Dave, Mossley plumbing Ltd.

Hi, as Dave mentioned it's complicated without hearing the problem, but if the sound only persists when it works at least then it may be necessary to check and adjust the gas valve. Sometimes it happens when it breaks and sounds like a whistle. In the combustion process it encounters too much gas and too little air. Adimo Company LTD - Mihai Didilica

It sounds like there’s a fault with the programmer if it’s coming on when not supposed to be. The noise could be a number of issues, central heating pump, gas valve not set correctly, fan noise, pressure relief valve letting off. It would be best to get an expert gas safe engineer in to fault find on the boiler.