[rellick]

Not sure if these are the same as you have Larry but I am going to order one of these thermostatic mixing valves for my coach, http://www.wattsindustries.com/image...xingValves.pdf
This way the hot water can be set quite high, or in my case about 190 deg with the heat exchanger and 140 deg with 110v it will automatically mix with cold to give the desired output temp. thus having more hot water for showering etc. No electricity needed works on temp. similar to a thermostat in an engine.