Leaking Hot water

Hi, I've got a brand new (2nd hand) Bosch Hydropower 16H tankless hot water heater. Since it was installed I have noticed it leaks a lot. I took the cover off and it looks like the bottom part (water section?) is leaking in a couple of places. maybe a seal or diaphragm? Can it be repaired or should I start again? I don't have a warranty as it was second hand, but it was brand new and unused.