Get involved - talk about the consumer issues that matter to you at which? conversation. If your combi boiler is in a cupboard, the cupboard is no less than 780mm (h) x 460mm (w) x 380mm (d) and there is space of 600mm in front of the boiler. Every repair includes a gas safety check. Subject to a satisfactory inspection of the existing heating system. An initial inspection is a visual inspection of your home electrical wiring and.