vaillant ecotec pro 28 buzzing noise issue

[Jimmy_J_Bob]

Hi, it sounds like a bee, happens intermittently with rads on only, goes off when you open hw tap

Video - https://drive.google.com/file/d/1eGBfQHfTCeM7s8z51rV2yhXCyRC2AppK/view?usp=sharing

Thanks

 

[Scott_D]

Could be one of a few components at fault.
Best get it checked over ASAP