We are often asked what type of boiler people have and this is not always as easy as it seems to identify. There are 4 major "types" of boiler... Combination boilers; have no "cylinder" or airing cupboard as they heat the hot water "on demand". System boilers; have an airing cupboard, but major components like the pump and sometimes the control valves are integrated into the boiler itself, these are often identified by having a pressure gauge present on the front of the casing. Heat-only; which are as basic as they sound, they simply provide heat and the system itself distributes the heat between the cylinder and radiators and Back-Boilers; which are a thing of the past now, these boilers sat in a chimney breast, often hidden behind a gas fire. All of these (Excluding Back Boilers) come in condensing and non-condensing variants, if it's a new boiler (Within the past 5 years) then it's likely to be condensing, as that is all we fit nowadays... You'll also notice that on cold days they produce a "white plume of smoke" from their flue, which non-condensing (standard efficiency boilers) will not. Now, here's the really tricky bit; sealed and open vented systems.... If it's a combi, then you have a sealed system. The rest could be either, so if you can identify a pressure gauage then you are likely to have a sealed system and if you have a small "jockey" tank of around 5-10 gallons in a loft, void or somewhere at high level in your property, then it's probably an Open Vented system.
Putting it altogether, you could have a "A condensing, open vented heat only" or "Standard efficiency, sealed system" boiler.