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SERVICING PRECAUTIONS
AIR RECHARGING IN COMPRESSOR
Test the refrigeration system connecting it electrically before
refilling operation. It is necessary to ascertain the function
of the motor-compressor and identify the defects
immediately. If defects have been found, empty the old
system of possible R-134a residue by breaking off the end
of the extension piece at its narrow point. (Figure 1)
Replace the filter and any damaged components. Unsolder
and pull off the piece remaining inside the service tube and
then attach an complete extension with male Hansen and
at last, solder it to the same tube again. (Figure 2)
POINT TO BE BROKEN
SERVICE TUBE EXTENSION
Figure 1
It is necessary to execute the soldering operation with
valve open so that the fumes caused by oil residue can
come out freely without blowholes between two tubes
during the heating the of the point to be soldered.
The extension fitted with the male Hansen is connected to
the female fitting of the vacuum pump tube. (Figure 3)
TO THE
VACUUM
PUMP
Air evacuating from the system begins as soon as the
pump starts. The refrigeration system must be kept under
vacuum until the reading on the low-pressure gauge
indicates vacuum (0 absolute, -1 atm., -760 mm hg). In any
case it is advisable to keep the pump running for about 30
minutes. (Figure 3)
If considerable leakage occurs, it will be necessary to stop
the vacuum pump and to add a small quantity of Freon to
the system. If vacuum should not be obtained (pressure
gauge can't fall to 1 atmosphere), start the refrigeration
unit and find the leakage with special leak-finder. When the
defective soldering point is visible, repair it after opening
the extension tube valve and reestablishing the normal
outside pressure inside the group.
Because the melted alloy is sucked into the tubes and
blocks them, the pressure must be rebalanced when
vacuum is in the system when soldering. As soon as the
CHARGE TUBE
FEMALE
EXTENSION
HANSEN
MALE HANSEN
SOLDERING POINT
Figure 2
PRESSURE
GAUGE
Figure 3
vacuum operation is over, add the quantity in grams of
R-134a to the refrigeration system. Remember that every
system has an exact quantity of R-134a that can be added
with a tolerance of ±5 grams. (Figure 4)
Before performing this operation (if the vacuum pump and
refilling cylinder are connected), make sure that the valve
placed between the vacuum pump and the refilling tube is
closed in order to keep the Freon for addition to the system.
(Figure 5)
FILLING OR
CHARGE TUBE
TO THE REFRIGERATION
SYSTEM
TO THE
VACUUM
PUMP
In addition, check the graduated scale on the cylinder for
the quantity of R-134a to be added, for example, if we
have 750 grams of Freon in the cylinder and must add 140
grams to the group, this amount will be reached when
R-134a has dropped to 610 grams, remembering that the
indicator shows a lower limit of meniscus. Do this after
choosing the scale corresponding to the gas pressure
different scales reported as the same gas pressure
indicated by the pressure gauge on the top of the column.
To make R-134a flow into the system, open the valve
placed at the base of the cylinder connected to the filling
tube. The amount of Freon cannot be added to the system
all at once because it may cause a blocking of motor-
compressor. Therefore, proceed by adding the original
quantity of about 20-30 grams and close the valve
immediately.
The pressure rises and the motor compressor must start
sucking the gas and lowering the pressure again. Open the
valve again, maintaining the same manner until reaching to
the quantity of R-134a established for the system being
charged. When the system is running, the suction pressure
must be stabilized between 0.30 to 0.6 (0.10 to 0.4)
atmosphere.
- 3 -
TO THE R-134a CYLINDER
TO THE REFRIGERATION
SYSTEM
Figure 4
VALVE TO BE OPENED
WHEN REFILLING
TO THE CHARGE
CYLINDER
VALVE TO BE CLOSED
AFTER VACUUM
Figure 5
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