Meter Clocking & Combustion Diagnostics
Gas meter clocking, combustion analysis, CO measurement, flue gas testing, manifold pressure measurement, and diagnostic instruments.
- Perform gas meter clocking and calculate firing rate
- Conduct combustion analysis and interpret CO readings
- Use diagnostic instruments for draft and pressure testing
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Gas Meter Clocking & Rate Calculation
What Is Meter Clocking
Meter clocking is the process of timing the gas meter to determine the actual firing rate of a gas appliance. By measuring how fast gas flows through the meter, you can calculate the actual BTU input and compare it to the rated input on the data plate.
Procedure
The Calculation
For natural gas (approximately 1,000 BTU per cubic foot):
BTU/h = (3600 / seconds per cubic foot) x BTU content per cubic foot
Example: If the meter takes 36 seconds to register 1 cubic foot:
- 3600 / 36 = 100 cubic feet per hour
- 100 x 1,000 BTU = 100,000 BTU/h input
Acceptable Range
The actual firing rate should be within +/- 5% of the rated input. Significantly higher indicates overfiring; significantly lower indicates underfiring. Both conditions require investigation.
Meter clocking determines the actual BTU input by timing gas flow through the meter. The result should be within +/- 5% of the data plate rating. Meter clocking is the definitive test for detecting overfiring or underfiring.