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TopicsNo matter
what you may have heard or read, there is no single way to
convert from R-12 to R-134a. R-134a is more tolerant of R-12 than
was first thought. In laboratory tests, amounts of up to 1
percent of R-12 remaining in the system seem to have little or no
effect on durability or performance.
How do you get down to 1 percent? Recovery/recycle machines will recover most of the free R-12 in the system. Draining or flushing will remove R-12 captured by the refrigerant oil and a deep vacuum of the system should catch the remainder. It should be noted that a deep vacuum will not remove the oil from the system. The oil must be drained from the compressor and replaced with a R-134a compatible oil.
Depending on the particular system it may also be necessary to drain the oil from other points such as the condenser, receiver tank and evaporator.
The dryer must be replaced with one containing XH-7 or XH-9 desiccants, which are compatible with R-134a. The standard R-12 service ports are legally required to be replaced with SAE approved R-134a service fittings to avoid inadvertently adding R-12 to the system.
A small leak in an R-12 system will leak even more with R-134a. The molecules of R-134a are much smaller than those of R-12. R-134a may permeate older R-12 hoses, especially those that are not nylon lined.
Since the R-134a system will operate at higher pressures, The high and low pressure switches may have to be replaced or adjusted. Unloader mechanisms may also require adjustment.
In some systems condenser capacity may require improvement in order for the system to cool properly. Other considerations are the probable replacement of hoses, O rings and seals.
Do not mix refrigerants such as R-22 with R-134a to improve cooling. Mixing of refrigerants is illegal and could result in a fine of $27,500.00.
This is intended as things to consider and should not be taken as a detailed retrofit plan.
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How do you get down to 1 percent? Recovery/recycle machines will recover most of the free R-12 in the system. Draining or flushing will remove R-12 captured by the refrigerant oil and a deep vacuum of the system should catch the remainder. It should be noted that a deep vacuum will not remove the oil from the system. The oil must be drained from the compressor and replaced with a R-134a compatible oil.
Depending on the particular system it may also be necessary to drain the oil from other points such as the condenser, receiver tank and evaporator.
The dryer must be replaced with one containing XH-7 or XH-9 desiccants, which are compatible with R-134a. The standard R-12 service ports are legally required to be replaced with SAE approved R-134a service fittings to avoid inadvertently adding R-12 to the system.
A small leak in an R-12 system will leak even more with R-134a. The molecules of R-134a are much smaller than those of R-12. R-134a may permeate older R-12 hoses, especially those that are not nylon lined.
Since the R-134a system will operate at higher pressures, The high and low pressure switches may have to be replaced or adjusted. Unloader mechanisms may also require adjustment.
In some systems condenser capacity may require improvement in order for the system to cool properly. Other considerations are the probable replacement of hoses, O rings and seals.
Do not mix refrigerants such as R-22 with R-134a to improve cooling. Mixing of refrigerants is illegal and could result in a fine of $27,500.00.
This is intended as things to consider and should not be taken as a detailed retrofit plan.