Air Conditioning......
07-17-2017, 09:51 AM
#1
Intermediate
Thread Starter
Air Conditioning......
...
Last edited by SMF; 08-26-2020 at 09:15 PM.
07-17-2017, 10:14 AM
#2
3 things to note about 134a in a R12 system
1) 134a has a smaller molecular weight (smaller molecules) than R12 so will have a higher leak rate that R12. ie, a hole not large enough for a R12 molecule to escape might be large enough for a 134a molecule to escape. Make sure your system is not low on refrigerant. Note that 134a likes to be at the low end of the charge scale for best cooling so do not over fill like you would with R12.
2) 134a is not as good a refrigerant as R12 (when using a R12 evap/expansion orifice) so expect 10-15% less cooling all else being the same.
3) 134a when used with a R12 compressor will be right at the 300 psi pressure line limit of the safety cutoff sensor so the compressor may cycle on-off a lot making the system not as affective. Again, under filling the 134a to the bare minimum will help this.
1) 134a has a smaller molecular weight (smaller molecules) than R12 so will have a higher leak rate that R12. ie, a hole not large enough for a R12 molecule to escape might be large enough for a 134a molecule to escape. Make sure your system is not low on refrigerant. Note that 134a likes to be at the low end of the charge scale for best cooling so do not over fill like you would with R12.
2) 134a is not as good a refrigerant as R12 (when using a R12 evap/expansion orifice) so expect 10-15% less cooling all else being the same.
3) 134a when used with a R12 compressor will be right at the 300 psi pressure line limit of the safety cutoff sensor so the compressor may cycle on-off a lot making the system not as affective. Again, under filling the 134a to the bare minimum will help this.
Last edited by Dynra Rockets; 07-17-2017 at 10:36 AM.
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HUSKER-Z (07-17-2017)