Hot water boiler for central heating

 

The photos show a hot water boiler in a central heating system. The through-pipes were brazed using the flame brazing method.
BrazeTec Silfos 2 or BrazeTec Silfos 94 with respective working temperatures of 740 and 760°C can be used as the brazing alloy. 

No flux is required with these alloys as the brazing involves a copper to copper connection.