> Joe, > According to the manual for the 3GM30F, cooling capacity is > 3.4 litres, or > 207.48 cu.in ( whatever they are) in the fresh water tank > with a further 0.8 litres (48.82) in the sub-tank . What about the coolant in the piping to and in the water heater heat exchanger? Stephen Cox Tewgwen #1141