Quote Originally Posted by harrisvh View Post
The original picture is of an indirect boiler, you might know of these as tankless heaters, multipoint heaters, geysers or ascots.



The second picture posted looks like it would be a direct boiler -these generally come with a back boiler and usually use heating elements, however I can see this particular one uses a heat exchanger.

They are both boilers however, just different types. The first picture is one that is generally used these days as they are more efficient because they only heat the water as needed. The second will heat the water from a back boiler or perhaps in this case directly from its own heat exchanger but these are generally being phased out in the UK as even the best insulated ones will still lose heat over time. Maybe you still have them over there because fuel is much cheaper???
Thanks for posting your 2 informative posts to explain to other members!