I need to replace my existing boiler with a new condensing boiler. As I understand it, a system boiler has built in pump and expansion vessel, whereas a regular boiler doesn't. My current CH system has a pump in the airing cupboard, but I do not think there is an expansion tank in the loft. Now I'm slightly confused because I'm not sure if the current boiler has a built-in expansion vessel. So I'm looking for clarification on whether I need a regular or system boiler.
Thanks.