Whether HC Blend can be used for retrofitting in place of R134a?
Yes, it can be used; the capillary may need some correction and electrical components will have to be changed to the non sparking type. It may be also worthwhile changing from POE oil (which is highly hygroscopic and creates problems in 134a systems) to Mineral oil. This would mean removing the oil from the compressor and flushing the system of all POE oil and then refilling with Mineral oil. There is a possibility that the Motor of the compressor may get overloaded with retrofit (just as it does when R12 is filled in a 134a system) and will depend on the rating of the original motor.
