Not sure if anyone here has dealings with continental water heaters but here goes. I'm from UK but living in Croatia. I have no gas here but plenty of forests so I put in a woodburning central heating system. I used a UK type indirect cylinder for the hot water and the system was pumped CH, gravity DHW. It never worked properly though, the water never got hot and I always needed to use the immersion heater. I discovered the reason for this when the heat exchanger developed a leak in the cylinder and the CH expansion tank overflowed. I took the immersion heater out, shone a light into the cylinder and could see the heat exchanger coil was small bore pipe, not suitable for gravity systems. I could not get a new UK type cylinder here so I bought a secondhand mains pressure indirect cylinder. It is only 1.8kw so not as quick to heat as the UK one but it seemed to be working on electric heat. As it is mains pressure I dispensed with the cold water tank and just connected it to the hot and cold circuits. Water pressure here is not high so I didn't fit a reducing valve. The first night I left it on and at 4 am had a flood, the shower pump had burst. Do these heaters have an integral expansion vessel or should I have fitted an external one? https://netkazan.hu/termek/6663/ari...jYKjDQiX8dID_FGygYwDk4y-E6lEm5fT0h963OElNgQWI