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Statement for R12 Compressors (Seizure and Procedure)
All DENSO compressors imported with R12 part number(047200,147200,247200) are supplied in R12 spec with Oil charge of Mineral oil (Type is NDoil 6 (Suniso 5GS)) These units are charged with Nitrogen and will not be modified to meet "Retrofit" conditions without considerable cost penalties.
For Australian market, where "Retrofit" upgrades have lead to extensive use of R134a in old R12 systems and where new R12 Compressor are purchased as direct replacements, modifications should be undertaken on retail side. We recommend that Original charge of Oil (Mineral oil) should be removed as part of the installation process. This will require Repairer to drain and discard oil upon installation, however he must be confident about system upgrade and ensure sufficient amount of R134a oil is within the system for lubrication of the compressor.
We highlight our "Retrofit procedure" from R12 to R134a refrigerant consist of :
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Charge of R134a must not exceed 93% of original R12 gas amount
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Add PAG oil amount equal to 120% of the original R12 Oil amount. (NDoil 8 for Swash type compressor and NDoil 9 for Vane type compressor). This oil is available in 250 ml tins.
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Replace the receiver drier and service fittings with R134a spec.
components.
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Add a label detailing the "retrofit details " carried out
Refer to DENSO General procedure for more detail
Our recommendation for mineral oil to be drained where possible is based upon system performance( it will reduce the cooling capacity of the A/C system) rather than its possible effect the compressor operation.
Our experience is that R12 mineral oil remaining in system will not cause any damage to New Compressors.
We highlight our Retrofit procedures, where the mineral oil has not been not removed but left in system.
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