gpm on tank water heaters

Snowmelt

is there a chart or can anyone tell me instead of sizing water heaters to the gpm of whats needed is there a chart that can give an estimate of how much water comes out of lets say 2 - 75 gallon water heaters and 1 65 gallon storage tank. that way I can say with 2 - 75 gallon i can give you 250 gallons of water in an hour and with a stage tank i can give you ex amount of water.

EBEBRATT-Ed

Look at the manufacturers instructions. There are many variables:

Inlet domestic water temp
Outlet domestic water temp
DHW temp is usually figured at a 100 deg rise

Then you have to look at the boiler side:
variables are boiler water temperature
TD on boiler water temp
GPM flow

Larry Weingarten

Hello, Tank type heaters should have a "first hour rating". It combines the stored hot water with what the unit can produce in an hour. That's your answer.

Yours, Larry