The retaining rings on the part sent to me seem even worse than those Alan K described.
Bought this instead making my own. The bypass valves are nice and it looked good until trying to use it.
Cant get them to seal - hand tightening the threads on the retaining rings jump. I've got unions between every device in the flow path - 6 before the heater install. None behave like this nor leak.
I ran the heater for a few minutes to test it - it works great. Sad I can't use it; have to leave it fully bypassed.
