Comments about Noritz Isolator Exp (Includes Pressure Relief Valve) - IK-WV-1:
These isolation valves work great. I am on my second tankless water heater. (Second house)
The first water heater I bought I tried to go to the hardware store, buy a series of valves and make my own isolation valves. It was ugly and not as cheap as I thought it would be. Of course, in my central Kansas hard water area, it is important to have some way to flush out mineral deposits, regardless of what it is. The only way, in my opinion, is to buy these purpose made isolation valves.