33
CAUTION
If you use a vacuum pump with mineral oil to
evacuate an R-134a system, it is ABSOLUTELY
ESSENTIAL to have a shut-off valve between
pump and your manifold gauge set as shown
in Figure E2. The hand valve must be closed
during all times when vacuum pump is
not operating. This will prevent migration
of mineral oil vapor into R134a/Ester oil
system. If vacuum pump should stop during
evacuation for any reason, the hand pump
shut-off valve must be closed immediately.
Refrigerant Leaks
A system with R-134a and Ester oil will become
saturated with moisture much faster than a system
with R-12 and mineral oil. If your leak was in the
low side of the refrigeration system when the
compressor is running the pressure in the low side
will go into a vacuum. As additional refrigerant
leaks out the system will go deeper into a vacuum.
The system running in this vacuum will allow air
and moisture to be pulled into the sealed system.
The moisture pulled in can then be mixed in to the
Ester oil in the compressor.
If the product has had a low side leak you will need
to install the two stage service dryer filter part
number 5303918288. You must heat the crankcase
area of the compressor using a heat gun on the
high heat setting though out the 30 minutes you are
running your vacuum pump to pull a vacuum on the
system. Every 4 to 5 minutes while you are running
your vacuum pump and heating the crankcase area
shake the compressor. By heating the crank- case
you are heating the oil in the compressor. This will
drive the moisture out of the oil. By shaking the
compressor this will allow the moisture to come to
the top of the oil faster so the vacuum pump can
remove the moisture from the system.
Electrolux Home products does not approve
the use of the Sweep Charge for sealed system
repair.
This method of servicing sealed systems
we know is often used to repair products in the
field. The Sweep Charge does not adequately
remove the moisture from the oil in the compressor
.
In a R-134a system you will need to replaced the
compressor if the product has had a low side leak
and you are servicing with the Sweep Charge
procedure.
R-134a refrigerant molecules are smaller than R-12
molecules. This means that R-134a will pass more
minor leaks and the rate of flow will be greater
than for R-12. Therefore, it is now more important
than ever to follow good brazing practices. Use a
good grade of silver solder. 45% silver solder is
recommended.
Hot Tube
Evaporator
Condenser
Compressor
2 Stage
Vacuum Pump
Heated
Charging
Cylinder
Process Tube
Adapters
Filter Drier
Pressure
Gauge
Compound
Gauge
Gauge
Manifold
T-Fitting
Figure E4
D - Refrigeration System
