meter is out of tolerance by more than .0025, then it must be adjusted or taken out of service. If this cannot
be done, then you may use the meter factor or meter percent error to adjust the meters registered reading on
the gallons pumped. The instructions for adjusting the meter are normally placed inside the top cover or in
the manufacturer's manual.
Meters must be checked under normal operating pressure and flow rate.
The prover must have the capacity for no less than the volume delivered through the meter in one
Fill the prover and then empty to the zero mark (dry run). This removes air pockets in the line and
warms up the meter.
During the dry run, the time and flow rate can be determined.
All gages and thermometers will be checked for accuracy.
All fittings and valves must be checked for leaks.
Verification Records and Reports.
Meter test results. The following information will need to be included on all meter verification
reports and records in order to obtain reliable meter performance rating:
Closing meter reading, after the prover is full.
Opening meter reading; this is for meters that cannot be set to zero.
Registration; quantity recorded by the meter.
Example: * Closing meter reading = 2,762
* Opening meter reading = 1,920
* Quantity Recorded = 2,762 - 1,920 = 842 gallons
Temperature of metered stream.
Temperature correction factor.
Registration corrected to 60 degrees Fahrenheit equals amount pumped times the correction factor.
Elapsed time. Elapsed time for test in seconds. (It will usually take less than a minute to fill the prover.)
Elapsed time for test in minutes. (The flow rate is in GPM, so seconds must be corrected to minutes.)
Rate of flow. The total register reading corrected to 60 degrees Fahrenheit divided by the elapsed time
for the test equals the rate of flow. (This tells you whether the meter is running at its prescribed flow rate
in one minute.)
Closing prover tank reading (percent). The prover is allowed to be in excess of the rated capacity by
+1percent or -1percent. (The graduations are in 10ths.) If the prover is rated at 840 gallons and the
closing percent is +2, then change the percent to a decimal (for example 2percent is changed to .002);
multiply the prover capacity (840) by .002 = 1.68 gallons. (Note: You pumped 841.68 gallons).
Closing prover tank readings (gallons). 841.68 gallons.
Opening prover tank reading is always 0.
Delivery. The closing prover tank reading minus the opening reading equals the delivered amount.
Prover temperature. If the prover has an upper and lower thermometer this would be the average of the
Temperature correction factor.
Delivery correction to 60 degrees Fahrenheit.
Meter factor. The meter factor equals the prover quantity at 60 degrees Fahrenheit divided by the meter
quantity at 60 degrees Fahrenheit divided by the meter quantity at 60 degrees Fahrenheit. The factor is
carried out to four (4) decimal places.
Meter certification record. The meter certification record in conjunction with the meter test results is
your proof that the meter has been properly calibrated. The following items will be included in the meter
certification and recorded to ensure that the meter has been properly tested and calibrated when required:
Date meter was verified.
Was meter factor within .0025.
Not Required___________Performed Date__________