22
C6.3.1/0116-0716/E
The diagram below compares the hygroscopic characteristics of POE oil with mineral oil
(moisture absorption in PPM at 25°C and 50% relative humidity).
Figure 19: Absorption of moisture in ester oil in comparison to mineral oil in ppm by weight at 25°C and 50%
relative humidity (h=hours)
If the moisture content of the oil in a refrigeration system reaches unacceptably high levels,
corrosion and copper plating may occur. The system should be evacuated down to 0.3 mbar or
lower. If there is uncertainty as to the moisture content in the system, an oil sample should be
taken and tested for moisture.
Sight glass/moisture indicators currently available can be used
with the HFC refrigerants and lubricants; however, the moisture indicator will just show the
moisture content of the refrigerant. The actual moisture level of POE would be higher than the
sight glass indicates. This is due to the high hygroscopicity of the POE oil. To determine the
actual moisture content of the lubricant, samples have to be taken from the system and
analysed.
6.4
Oil additives
Although Emerson Climate Technologies cannot comment on any specific product, from our own
testing and past experience, we do not recommend the use of any additive to reduce
compressor bearing losses or for any other purpose. Furthermore, the long-term chemical
stability of any additive in the presence of refrigerant, low and high temperatures, and materials
commonly found in refrigeration systems is complex and difficult to evaluate without rigorously
controlled chemical laboratory testing. The use of additives without adequate testing may result
in malfunction or premature failure of components in the system and, in specific cases, in voiding
the warranty on the component.
6.5 Unbrazing system components
WARNING
Explosive flame! Burning!
Oil-refrigerant mixtures are highly flammable.
Remove all refrigerant before opening the system. Avoid working with an
unshielded flame in a refrigerant charged system.
Before opening up a system it is important to remove all refrigerant from both the high and low
sides of the system. If a brazing torch is then applied to the low side while the low side shell and
suction line contain pressure, the pressurized refrigerant and oil mixture could ignite when it
escapes and contacts the brazing flame. To prevent this occurrence, it is important to check both
the high and low sides with manifold gauges before unbrazing. Instructions should be provided in
appropriate product literature and assembly (line repair) areas. If compressor removal is
required, the compressor should be cut out of system rather than unbrazed.
7
Dismantling & disposal
Removing oil and refrigerant:
Do not disperse in the environment.
Use the correct equipment and method of removal.
Dispose of oil and refrigerant properly.
Dispose of compressor properly.
