Hi Dotchin
My last home had it's combi boiler in a cupboard in the bedroom. My Son also has his in a bedroom. The cupboard door must have two sets of vents for safety, also make sure with any boiler you have a Carbon Monoxide Detector in the same room.
Hope this helps
i don't know the regulations on this but i would say NO!!
you are asleep and carbonmonoxide + sleep is not good.
plumbers will probably shoot me down in flames, but thats my view on it. better to be save than sorry.
All modern combi boilers are a fan assisted flues and room sealed appliance's than you can put it wherever you like including the bedrooms and in un-ventilated cupboards. They get there air supply from the outside so no need to have porpose provided ventilation and of coarse the products of combustion are also expelled to the outside. They opperate at a much lower temperature as well now-a-days so no need for vents in the doors to assist in cooling or combustion. BUT as always the manufacture's instructions must be adhered to and if they state any vents are to be installed then they must be. Etc...