Service manual

SERVICING
36
The equipment required to thoroughly evacuate the sys-
tem is a high vacuum pump, capable of producing a vacuum
equivalent to 25 microns absolute and a thermocouple
vacuum gauge to give a true reading of the vacuum in the
system.
NOTE: Never use the system compressor as a vacuum
pump or run when under a high vacuum. Motor damage
could occur.
WARNING
SCROLL COMPRESSORS: DO NOT FRONT SEAT THE
SERVICE VALVE(S) WITH THE COMPRESSOR OPER-
ATING IN AN ATTEMPT TO SAVE REFRIGERANT. WITH
THE SUCTION LINE OF THE COMPRESSOR CLOSED
OR SEVERALLY RESTRICTED, THE SCROLL COM-
PRESSOR CAN AND WILL DRAW A DEEP VACUUM
VERY QUICKLY. THIS VACUUM CAN CAUSE INTER-
NAL ARCING OF THE FUSITE RESULTING IN A DAM-
AGED OR FAILED COMPRESSOR.
A. HIGH SIDE VALVE
B. LOW SIDE VALVE
C. VACUUM PUMP
D. THERMOCOUPLE GAUGE
E. MANIFOLD GAUGE
F. CHARGING CYLINDER
C
A
B
E
D
HIGH VACUUM PUMP
LARGE DIAMETER
BRAIDED VACUUM
HOSES
TO
RELATED
GAUGE
PORTS OF
COND. UNIT
HIGH VACUUM
MANIFOLD
LOW SIDE
GAUGE
HIGH SIDE
GAUGE
DIAL-A-CHARGE
CHARGING CYLINDER
THERMOCOUPLE
VACUUM
GAUGE
F
EVACUATION
1. Connect the vacuum pump, vacuum tight manifold set
with high vacuum hoses, thermocouple vacuum gauge
and charging cylinder as shown.
2. If the service dill valves are to be used for evacuation, it
is recommended that a core remover be used to lift the
core for greater efficiency.
3. Start the vacuum pump and open the shut off valve to
the high vacuum gauge manifold only. After the com-
pound gauge (low side) has dropped to approximately
29 inches of vacuum, open the valve to the vacuum
thermocouple gauge. See that the vacuum pump will
blank-off to a maximum of 25 microns. A high vacuum
pump can only produce a good vacuum if its oil is non-
contaminated.
4. If the vacuum pump is working properly, close the valve
to the vacuum thermocouple gauge and open the high
and low side valves to the high vacuum manifold set.
With the valve on the charging cylinder closed, open
the manifold valve to the cylinder.
5. Evacuate the system to at least 29 inches gauge be-
fore opening valve to thermocouple vacuum gauge.
6. Continue to evacuate to a minimum of 250 microns.
Close valve to vacuum pump and watch rate of rise. If
vacuum does not rise above 1500 microns in three to
five minutes, system can be considered properly evacu-
ated.
7. If thermocouple vacuum gauge continues to rise and
levels off at about 5000 microns, moisture and non-con-
densables are still present. If gauge continues to rise a
leak is present. Repair and re-evacuate.
8. Close valve to thermocouple vacuum gauge and vacuum
pump. Shut off pump and prepare to charge.
S-103 CHARGING
Charge the system with the exact amount of refrigerant.
Refer to the specification section or check the unit name-
plates for the correct refrigerant charge.
An inaccurately charged system will cause future problems.
1. When using an ambient compensated calibrated charg-
ing cylinder, allow liquid refrigerant only to enter the high
side.
2. After the system will take all it will take, close the valve
on the high side of the charging manifold.
3. Start the system and charge the balance of the refriger-
ant through the low side. DO NOT charge in a liquid
form.
4. With the system still running, close the valve on the
charging cylinder. At this time, you may still have some
liquid refrigerant in the charging cylinder hose and will
definitely have liquid in the liquid hose. Reseat the liq-
uid line core. Slowly open the high side manifold valve
and transfer the liquid refrigerant from the liquid line hose
and charging cylinder hose into the suction service valve
port. CAREFUL: Watch so that liquid refrigerant does
not enter the compressor.
5. With the system still running, reseat the suction valve
core, remove hose and reinstall both valve core caps.
6. Check system for leaks.
NOTE: THIS CHARGING PROCEDURE CAN ONLY BE
DONE IN THE COOLING MODE OF OPERATION. ALL
MODELS WITH COMPRESSOR PROCESS TUBE AC-
CESS VALVE CAN BE PROCESSED IN HEATING CYCLE
IF THIS VALVE IS USED.