Hi and thanks in advance for the great info I've already gotten off this forum!
I recently had a steam shower generator installed. At the rough in inspection, the inspector said that I needed a dual check valve in the line that connects the autoflush drain from the generator, which is gravity fed not pumped, to the DWV. The way the line is plumbed is from the generator with 1/2" copper to the PVC shower drain
pipe before the shower trap.
The plumber insists that I don't need a dual check valve, and installed a swing check valve. The plumber also thinks that a dual check valve may cause my steam generator to malfunction. I've called the maker of the steam unit and technical support there was not much help.
Can somebody please tell me what to do. Who's right - the plumber or the inspector? Can you explain how each of these valves work so that I can weigh in during the next rough-in inspection?
Thanks for your help!