One of the great things about hydronic heating systems is that they are really fairly straightforward to understand. There are only really three vital components and hydro heat pumps are simply one of these components.
This is true of all the forced hot water systems from hydronic radiant floor heat through to wall hanging radiators.
In general then, hydronic heating systems consist of a boiler to heat the water, the pump which send the heated water out to the system, and the pipes and/or radiators that form the radiating parts. The last part, the pipes and so on, is the main difference between the various types of hot water radiant heat.
For example, baseboard hot water heating systems use small but noticeable radiators, whereas the underfloor systems use larger pipes to criss-cross the floor that are themselves the radiators.
The life time of quality home hot water boilers is quite long and should surpass fifteen years. Quite often the weakest link in a system in the pump. Luckily these are the cheapest part of the system and easy to replace. If you keep the system maintained you should expect your service engineer to be able to sort out any potential pump problem at a low cost with the minimum of fuss.