On 2008-07-26, Rick-Meister wrote:

In addition, the burners in many demand WHs are rated for a
2.5gallon/minute flow rate. But most dishwashers don't fill at the
rate of 2.5 gallons/minute. If the dishwasher fills at the rate of 1
gallon per minute, all those extra btu's go right up the flu.

That's not true--the demand gas water heater has a modulating burner
and adjusts to the flow rate.

Wayne