Sharp AF-S100RX, Service Manual

Page: 44 / 62

Section 5 Sealed System
5 -18
Vacuum Pump Maintenance
It is absolutely essential to maintain your vacuum pump
required oil changes at the recommended intervals.
Vacuum pump oil should always be changed after
evacuating a contaminated system. Vacuum pump
performance should be checked periodically with a
micron gauge.
Vacuum pump suppliers may or may not recommend
in the system being evacuated. Some manufacturers
R-410A systems.
Robinair has stated that their current and discontinued
vacuum pump models, using mineral oil currently
specified for use in their vacuum pumps, can be used
to evacuate R-134a (R410a)/Polyol Ester oil systems.
Robinair also states that it is acceptable to alternate
between evacuating R-12/mineral oil and R-134a
(R410a)/Polyol Ester oil systems without adversely
For other brands of vacuum pumps, check with the
manufacturer for restrictions and guidelines when using
with R-410A.
If you use a vacuum pump with mineral oil to
evacuate an R-410A system, it is ABSOLUTELY
ESSENTIAL to have a shut-off valve between
pump and your manifold gauge set. The hand
valve must be closed during all times when
vacuum pump is not operating. This will prevent
migration of mineral oil vapor into R-410A/
Polyol Ester oil systems. If the vacuum pump
should stop during evacuation for any reason,
the hand pump shut-off valve must be closed
immediately.
To achieve the required 29.9 inch (500 micron) vacuum,
a properly maintained two-stage vacuum pump in good
condition is required. A two stage pump can reach a
deeper vacuum than a single stage because the exhaust
from the first pumping stage is discharged into the
second pumping stage. This means the second stage
begins pumping at a lower pressure so a lower ultimate
vacuum can be achieved.
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Ó·½®±²-
Þ±·´·²¹ б·²¬
±º É¿¬»® pÚ
îèòçìð îëððð ééòç
îçòëíð ïðððð ëîòð
îçòèíî ìêðð íîòð
îçòèèî ïððð ïòð
îçòçðï ëðð óïïòî
îçòçïë ïëð óíîòè
îçòçïé ïðð óíèòî
îçòçïç ëð óìçòð
Figure 5 -8. Two Stage Vacuum Pump