Advanced Pressure Calibration - Fieldpiece SMAN SM480V Operator's Manual

Advanced Pressure Calibration

Typical HVACR service does not require this
procedure, but you can occassionally calibrate the
pressure sensors to maintain highest accuracy
It works by measuring the temperature of
virgin refrigerant and applying an offset to match
the pressure to that refrigerant's P-T chart
1. Calibrate a beaded thermocouple to the ODDB jack (page 25).
2. Store a virgin refrigerant cylinder, upright and untouched, in the
stable ambient environment for at least 24 hours.
3. Leaving the cylinder in the same place it was left to stabilize,
connect the cylinder to either the HIGH or LOW side port.
4. Close VAC and REF valves and cap the unused port.
If you don't have caps with seals, you can connect both ends of a
refrigerant hose to the unused ports or hose seats. Some refrigerant
will remain in the hoses which you need to recover after calibration.
5. Use ARROWS to select the refrigerant type in the cylinder.
6. Use tape to attach the ODDB thermocouple bead halfway up the
cylinder to measure the temperature of the refrigerant.
7. Press VIEW if ODDB is not shown.
8. Open both HIGH and LOW side manifold valves.
9. Open the refrigerant cylinder valve.
The pressure inside cylinder should now be displayed on both HIGH
and LOW side pressure sensors.
10. Allow the pressure readings and ODDB temperature to stabilize.
11. Press MENU.
12. Use ARROWS to show Adv Pressure Cal.
13. Press ENTER to initiate calibration of the pressure sensors.
14. Each pressure sensor will briefly display "Good" if successful or "Err"
if unsuccessful, then return to normal operating mode.
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Troubleshooting an "Err" message
1. Measured pressure was less than 10 psig.
• Refrigerant cylinder may be nearly empty.
• Valves may be closed.
2. Measured pressure was not within ±3psig of VSAT pressure on
the P-T chart.
• Thermocouple may not have been calibrated properly.
• Thermocouple may not have been attached properly to cylinder.
• Thermocouple may have not been connected to ODDB jack.
• Refrigerant cylinder pressure was unstable.
• Refrigerant cylinder temperature was unstable.
• Refrigerant selected did not match refrigerant in cylinder.
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