# Metric Firing rate for gas meter

• posted on November 30, 2006, 11:07 pm

My gas meter is metric with one of the dials calibrated to .01 cu meters. If one revolution takes 16 secs, what is the gas consumption rate according to the table below?
I get 80,000btu as follows:
1 cu ft = 12^3 cu in or 1728 1 cu meter = 39.37^3 cu in or 61023 .01 cu meters = 610 cu in therefore to extrapolate to 1 cu ft: multiply 16 secs by = 1728/610 or 2.8 which is 45 secs
Does this make sense?
Checking the Firing Rate -"Clocking the Meter"
Checking the firing rate of a furnace is a very important element of the installation procedure. Over-firing can cause premature heat exchanger failure. This is done by measuring the time it takes to consume 1 cubic foot of gas.
When performing this procedure it is important to activate the furnace for about 10-15 minutes, and all the other gas appliances are turned off. Adjust inlet gas pressure to between 5 and 7 inches water column then time the meter for 2 revolutions and then divide by 2 to get the time for one revolution. Need to check meter size (1 CuFt or 10 CuFt).
The following table shows approximate gas consumption (measured in cubic feet per hour), and the gas input (measured in Btu/Hr), based on Natural gas whose caloric value ranges from 900 to 1050 Btu/cu. ft. We are assuming 1000 Btu/cu. ft.
Gas Input (Btu/Hr) (Caloric Value of Gas x 3600) / Meter Time (seconds)
This chart assumes a 1 CuFt meter size
Seconds per cubic feet Consumption cubic feet per hour Gas input btu/hr @ 1000 btu/cu ft 20 180 180,000 22 164 164,000 24 150 150,000 26 138 138,000 28 129 129,000 30 120 120,000 32 113 113,000 34 106 106,000 36 100 100,000 38 95 95,000 40 90 90,000 42 86 86,000 44 82 82,000 46 78 78,000 48 75 75,000 50 72 72,000 52 69 69,000 54 67 67,000 56 64 64,000 58 62 62,000 60 60 60,000 62 58 58,000 64 56 56,000 66 54 54,000 68 53 53,000 70 51 51,000 72 50 50,000 74 48 48,000 76 47 47,000 78 46 46,000 80 45 45,000 82 44 44,000 84 43 43,000 86 42 42,000 88 41 41,000 90 40 40,000