I have a site with several sterilisers installed. They have a 15mm chromed pipe outlet for the waste which is opened once a day, ditching 85°C water. Currently, they all have the 15mm pipe terminating into a 22mm overflow waste non return valve, and these fail regularly. The 22mm overflow pipe leaving the non return valve also overheats and bows.
This is the part:
http://www.plumbcenter.co.uk/product/mcalpine-convalve-in-line-non-return-valve-...It seems to me that a metal version would be better, to cope with the heat, and 22mm metal pipe, not overflow. The overflow eventually terminates into the 1.5" wastes, and these are not affected by the hot water.
Any ideas on the best way forward?