FD-4A

Calibration of FD-4A

Summary:
A step-by-step tutorial on calibrating your FD-4A 4 gas monitor. 

Model: 
FD-4A

Calibration Frequency: 
At least every 12 months.

Calibration Kit Items Required:

  1. Calibration Gas (Multigas)
  2. Calibration Gas Regulator (C10)
  3. Tubing

▶️ Tutorial Calibration Video

 

✅ STEP 1: ZERO Calibrate CO, H2S, and EX to 0 ppm and O2 to 20.9% using Fresh Air.

  1. Power on your 4 gas detector and allow 2 minutes for stabilization in fresh air.
  2. The 4 gas detector may not read precisely 0 ppm for CO, H2S, or EX. If it does not, you will need to perform a zero calibration. Also, the O2 sensor may be a bit lower or higher than 20.9%. If so, undertake a 20.9% fresh air calibration for the O2 sensor, as explained below.
  3. To zero calibrate CO, EX, and H2S, press the middle button and go to the Menu Screen.
  4. Select "ZERO SET" by pressing the middle button.
  5. Then, using the up and down buttons, select the sensor you wish to zero calibrate from CO, EX, or H2S, then press the enter (middle) button.
  6. Then press "Save". 
  7. Done. Repeat starting at step (5) similarly for other sensors (except O2).
  8. For the O2 sensor to read 20.9% in fresh air. Go to the Menu Screen.
  9. Select "GAS CHECK" by pressing the middle button.
  10. Enter passcode: 1111
  11. Then, using the up and down buttons, select either O2 then press the enter (middle) button.
  12. Confirm STANDARD VALUE shows 20.9%. This tells the detector to calibrate to 20.9%, then press ENTER.
  13. Then press SAVE to confirm the calibration data point.
  14. Done!
  15. This completes zero calibration of H2S, CO, and EX sensors and calibration of the O2 sensor to 20.9%.

✅ STEP 2: SPAN Calibration of CO, H2S, and EX LEL.

  1. Expose the 4-gas monitor to your calibration reference gas for 2 minutes or until the reading has stabilized. Use a flow rate of 0.5 LPM and connect the gas to the gas detector via the FD-4A calibration cap.
  2. Select "GAS CHECK" from the Menu Screen.
  3. Enter passcode: 1111
  4. Then, using the up and down buttons, select either CO, H2S and EX then press the enter (middle) button.
  5. Then, you are in the STANDARD VALUE selection. Enter the span reference gas value for the respective gas sensor selected, which is the same value shown on your gas bottle or, more precisely, on your calibration gas bottle Certificate of Analysis.
  6. Then press "ENTER".
  7. Then you will be displayed the MEASURED VALUE. The display shows the detected gas value. Ensure this has stabilized. Then press "Save".
  8. Repeat this process for the CO, H2S, and EX sensors.

  9. Once completed, the analyzer is span-calibrated, and the calibrated value is shown on the main screen. 

✅ STEP 3: Verification

  1. Allow the gas detector to stabilize in fresh air for 5 minutes, confirming the CO, H2S, and EX LEL are reading 0, and O2 is reading 20.9%.
  2. Expose the analyzer to the calibration reference gas to verify the calibration and detection repeatability. Expose for 2 minutes.
  3. If the gas detector reading is within +/- 2% F.S. of the calibration gas value, this is considered a PASS. For example, FD-4A has a full scale of 100 %LEL for the EX sensor. The unit was calibrated to a reference gas of 50 %LEL. Then, a PASS range is +/-2% of 50 %LEL. Therefore, a PASS is between 48 %LEL and 52 %LEL. 
  4. Once verified, your unit is properly calibrated and ready for operation.
  5. Don't forget to document the calibration event in your gas analyzer log book. Place a reminder calibration date sticker on the unit for the next calibration event.