Compression fittings for steel and copper tubing - Compression fittings are for connecting Danfoss valves to circuits in heating systems only. Compression fittings are used for connecting steel and copper pipes in accordance with EN10305-1 and EN1057. Always observe the maximum operating pressure and temperature which are given by the tubing manufacturer: 10 bar and 120°C One set consists of one olive and one union nut. It is recommended to use supporting bushes with soft pipes