WITH Chinese manufacturers now producing air conditioners to run on propane and at least one major European manufacturer known to be investigating the use of other flammable refrigerants, it might come as no surprise to learn that the German environment ministry is behind a new guide on how to convert existing split systems air conditioners to hydrocarbon refrigerants.
The publisher, German International Cooperation (GIZ), maintains that despite recommendations to the contrary, conversions of existing equipment to flammable refrigerants are being carried out and are likely to continue to do so. The booklet, it says, has been produced in order to try and ensure it is done safely.

Refrigerants that may be used for such purposes, says the booklet, could include R290
(propane) or R1290 (propylene), where, for example, the system was previously charged with R22 or R407C.

The conversion guide discusses some of the considerations to take into account before deciding whether to go ahead with the conversion of a particular system, such as the type and complexity of the equipment to be modified or the quantities of refrigerant involved.

It discusses the type of systems that are typically suitable for conversion to hydrocarbons, and provides a decision chart to assist with evaluating the suitability of the equipment.

Companies are encouraged to establish special conversion workshops, policies and carry out upgrades of tools and equipment.

The important stages in evaluating and carrying out conversions are described in fourteen steps, from estimating the required hydrocarbon refrigerant charge size, to design changes, sealing of the system, refrigerant charging, etc.

The publication highlights that system design changes are critical to ensuring that safety requirements are met and discusses the typical major considerations with particular attention paid to addressing the potential sources of ignition.

Finally, the booklet gives an example of the different steps discussed for the case of converting a split air conditioner from R22 to R290 (propane).

As yet there has been no response from manufacturers as to the ramifications for warranties, etc.