I tried the mixer valve and had problems with it,.. it reduced the flow rate through my heater too much and the overheat cut out kept kicking in,..... hence the need for a smaller heater!
I plan to put the L5 into the housing of my old heater (The dimensions seem about right on paper) as its designed to attach to a flue and be vented out the roof. That's the only downside I can see with the L5,.. but adding a hood/flue should be easy for anyone who wants to.
