General Assist Technical Guidance

How to Check the Refrigerant Level

Understanding refrigerant charge, leak testing and correct system recharging
A Fujitsu General air conditioner operates as a closed, sealed refrigeration system. Refrigerant is not consumed during normal operation and should not require routine topping up. If the system is low on refrigerant, this generally indicates a leak that must be located and repaired.
Licensed technician required: Refrigerant handling, recovery, leak testing, evacuation and charging must only be completed by a suitably licensed refrigeration and air conditioning technician. Do not attempt to open the refrigerant circuit or add refrigerant yourself.

1. Refrigerant does not get used up

Unlike fuel, refrigerant circulates continuously through the indoor unit, outdoor unit and connecting pipework. Under normal conditions, the quantity of refrigerant remains unchanged for the life of the system.

Important: Adding refrigerant without finding and repairing the cause of the loss is not a complete repair. The system may lose charge again and could suffer further damage or reduced performance.

2. How a technician checks the refrigerant charge

Step 1 - Assess system operation

The technician may initially check operating temperatures, pressures, airflow, electrical readings and system fault history. These checks can indicate that further refrigerant investigation is required, but they do not always confirm the exact quantity of refrigerant in the system.

Step 2 - Recover and weigh the refrigerant

The most reliable method of confirming the refrigerant quantity is to recover the complete charge using approved recovery equipment and weigh the amount removed.

The recovered quantity is then compared with the factory charge shown on the outdoor unit nameplate, together with any additional charge required for the installed pipe length.

Step 3 - Leak-test the system

If the recovered amount is below the required charge, the technician should inspect and test the refrigeration circuit, including:

  • Indoor and outdoor unit coils and refrigerant components.
  • Connecting pipework and insulation.
  • Flare joints, brazed joints and service valves.
  • Valve caps, service-port cores and accessible fittings.
  • Areas showing oil residue, corrosion or physical damage.

Step 4 - Repair and evacuate

Once the leak has been found, the affected component or joint must be repaired. The refrigeration circuit is then evacuated with a vacuum pump to remove air and moisture before recharging.

Step 5 - Recharge by weight

The technician weighs in the specified refrigerant charge. The correct charge must account for the factory specification and, where applicable, the installed refrigerant pipe length.

StagePurpose
Operational assessmentChecks whether system performance suggests a refrigeration, airflow, control or electrical issue.
Recover and weighConfirms the actual amount of refrigerant removed from the system.
Leak testingIdentifies why refrigerant was lost.
EvacuationRemoves air and moisture from the sealed circuit.
Recharge by weightRestores the precise specified refrigerant quantity.

3. Possible signs of low refrigerant

Low refrigerant can contribute to the following symptoms:

  • Reduced cooling or heating performance.
  • Long operating periods without reaching the set temperature.
  • Ice forming on refrigerant pipework or the indoor coil.
  • Refrigeration-related fault codes or abnormal system pressures.
  • Oil staining around joints, valves or coils.
  • Unusual compressor operation or increased energy use.
These symptoms do not prove that the system is low on refrigerant. Dirty filters, restricted airflow, incorrect settings, blocked coils, faulty sensors, installation problems and other component faults can produce similar symptoms.

4. Warranty considerations

Fujitsu General warranty applies to defects arising from the manufacture of the product, subject to the applicable warranty terms and conditions.

Refrigerant loss caused by installation workmanship or external factors may not be covered. Examples can include:

  • Incorrectly made or tightened flare connections.
  • Leaking field-installed pipework or brazed joints.
  • Damage caused during installation, building works or later service activity.
  • Corrosion, impact damage or environmental causes.
  • Incorrect additional refrigerant charge for the installed pipe length.
For warranty assessment: The attending technician should record the refrigerant recovered, required charge, leak location, test method, repair completed and final charge weighed into the system. Photographs and commissioning readings may also be required.

5. Summary

  • Air conditioners do not normally consume refrigerant.
  • A low charge usually indicates a leak or an incorrect installation charge.
  • Operating pressures alone may not confirm the exact refrigerant quantity.
  • The definitive check is to recover and weigh the refrigerant.
  • Any leak must be repaired before evacuation and recharging.
  • All refrigerant work must be completed by a licensed technician.
If the air conditioner is not cooling or heating correctly, arrange an inspection by a licensed air conditioning technician or Fujitsu General Authorised Service Agent. Continued operation with an incorrect refrigerant charge may reduce efficiency and could damage the system.
This article provides general technical guidance. The applicable installation manual, service documentation, refrigerant-handling requirements and local regulations must always be followed.