Gas PipingQuestion 240 of 360
A tankless natural gas water heater lists an input of 199,000 BTU/hr. Using 1,000 BTU per cubic foot, what gas demand must the branch supplying it be sized for?
a.19.9 cfh
b.1,990 cfh
c.199 cfh
d.99 cfh
Explanation
Divide input by heating value: 199,000 divided by 1,000 equals 199 cubic feet per hour. High-input tankless heaters often need a larger branch and meter than a tank-type unit because of this large instantaneous demand. Verify the meter and upstream piping can also supply this cfh at the required pressure.
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