Copyright © Ian Russell 2005

Air conditioning recharge (R12) 2

All science is either physics or stamp collecting.

(Ernest Rutherford)

Changing the R12 system over to R134a is not as simple as just replacing the refrigerant.  You should not attempt to top up an R12 system using an R134a DIY re-charge kit - the refrigerants and oils used are not compatible.  In order to change from R12 to R134a you will need to completely evacuate the system, change the type of oil used in the system and the compressor, fit a new receiver-drier and a new pressure switch and replace some of the hoses with less permeable ones due to the different nature of the refrigerants.  It is a pretty big job!


However, there are “drop in” replacement refrigerants available and these include R413a refrigerants like ISCEON 49 and OZEON (note the difference between R413a and R134a!). 


If you are continually troubled by air con problems then it is worth visiting an automotive air conditioning engineer who can check for and repair any leaks, evacuate the system and replace the oil and refrigerant.  The air conditioning system on the Esprit uses 1.4 kg (3lbs) of refrigerant.


When the pressure in the system falls below a certain value, a cut off switch on the receiver-drier disables the whole system.  Topping up the refrigerant increases the pressure deactivating the switch and enabling the air con.


This procedure covers the simple job of topping up the refrigerant level with a suitable drop in replacement refrigerant.