General Assist Technical Reference

Retrofitting or Converting Refrigerant Systems

Refrigerant substitution, system modification and service requirements
Guidance for General / AIRSTAGE air conditioning and refrigeration equipment
General position: A unit must only be charged with the refrigerant specified on its nameplate. General does not approve changing a system to a different refrigerant unless that conversion has been specifically designed, tested and approved for that product.

Why refrigerant conversion is not approved

Air conditioning equipment is designed, tested and registered for the refrigerant identified on the product nameplate. Changing refrigerant can affect operating pressure, compressor lubrication, component suitability, electrical safety and the refrigerant safety classification for which the equipment was originally designed.

Key rule: The refrigerant shown on the nameplate is the refrigerant that must be used in the system.

Common conversion examples

R22 system converted to R410A

  • The existing pipework may not be rated for the higher operating pressures associated with R410A.
  • The compressor oil used in the original system is not compatible with R410A.
  • The system was designed and manufactured to operate with R22, not R410A.

R410A system converted to R32

  • The system was not designed for a mildly flammable refrigerant.
  • The compressor oil is different.
  • The compressor and system have not been registered as an R32 product under the applicable product requirements.

R410A, R32 or R22 system converted to a hydrocarbon refrigerant

  • The system was not designed to operate with a flammable hydrocarbon refrigerant.
  • The product has not been registered to operate with a refrigerant other than the refrigerant stated on the nameplate.
  • General service agents are not instructed or trained to service General equipment that has been converted to a hydrocarbon refrigerant.
Important: A refrigerant having a similar operating pressure does not make it a suitable or approved replacement. Refrigerant classification, compressor oil, component construction, electrical requirements and product compliance must also be considered.

AIRAH guidance on converting systems

The supplied AIRAH training material describes conversion as changing a system from one refrigerant to another where the new refrigerant has a higher flammability or toxicity classification. An example provided is converting an R22 (A1) air conditioner to R290 (A3).

The training material states that this type of conversion should not be undertaken unless the person carrying out the work has:

  • Competence in the design of refrigerating equipment.
  • Detailed knowledge of the applicable electrical safety standards.
  • Competence to recognise when additional engineering controls are required and how to implement them.
Modification responsibility: The AIRAH material also notes that modifying an electrical appliance places responsibility for the electrical safety of the modified appliance on the person undertaking the modification. It explains that electrical safety regulators may regard the modified equipment as a new electrical appliance, with the modifier effectively becoming the equipment manufacturer / responsible supplier and potentially needing to provide evidence of compliance.

Use of the term “drop-in replacement”

The AIRAH material cautions against using the term drop-in replacement where the replacement refrigerant has a different safety classification. The term should only be used where one refrigerant is being replaced by another refrigerant of the same safety classification. The example provided is replacing R22 (A1) with R438 or R407C, which are also A1.

General service position

Do not service a converted system in its modified condition. If a General field technician or authorised service agent identifies that a system has been retrofitted or charged with a refrigerant other than that specified on the nameplate, the customer is to be advised that the equipment must be returned to its original designed condition before General or its service agent works on the product.
StepRequired action
1Confirm the refrigerant specified on the equipment nameplate.
2Establish whether a different refrigerant has been introduced into the system.
3If the system has been converted, do not proceed with General service work in the modified condition.
4Advise the customer that the system must be returned to the refrigerant and configuration for which it was originally designed before service can proceed.
Summary: General equipment is to be operated and serviced with the refrigerant specified on the product nameplate. Retrofitting or converting the equipment to another refrigerant is not an approved repair method unless specifically supported by General for that model.