MasterCool 99903 Operating Instructions Manual page 4

4-WAY DIGITAL VALVE BODY CONFIGURATION
LOW
LOW
LOW
VAC REF
LOW
REF
IMPORTANT NOTES FOR SERVICING AC/R SYSTEM
LOW
A system that has been opened or one that is found to be excessively low on refrigerant pressure as a
result of a leak, must be fully evacuated by means of recovery/recycling and deep vacuum. A system
that has been evacuated must be repaired, leak tested and evacuated again before charging.
DIAGNOSING THE SYSTEM PRESSURE AND TEMPERATURE
VAC
1. Make sure all valves on the manifold are closed.
2. Connect the blue and red hose from the low and high side of the manifold to the system.
3. Start the system and allow some time for the true pressure reading on the manifold to appear and
stabilize.
CHARGING
1. Verify that all valves on the manifold are shut completely.
2. Turn the A/C system and manifold ON.
3. Connect the other end of the yellow hose to Refrigerant Gas supply.
4. Open refrigerant valve and low side valve slowly and start charging. (Follow refrigerant
manufacturer's instructions for proper dispensing. Use an electronic scale for accurate charging
(Mastercool #98210-A)
5. When charging is finished, close the valve on the tank and allow some time for the refrigerant to be
evacuated from the hoses and manifold.
6. Close the low side & refrigerant valve and disconnect the hose(s) from the system.
VACUUM GAUGE OPERATION (SEE FIG.B)
• Press the POWER button to turn the unit ON. Allow 10 seconds for the unit to initialize.
• Close all valves.
• Connect the high side and low side hoses to the system and the yellow or black hose to the vacuum
pump.
• Connect the vacuum cable to the manifold. Connect the other end of the vacuum gauge to the system.
(An additional TEE fitting (Mastercool #99333) or an isolation valve may be required.)
Press the VACUUM button and select the desired unit.
Press ENTER to confirm.
FIG. B
CONNECT TO
SYSTEM OR
TO LOW SIDE
(BLUE)
• Start the vacuum pump and open high, low and vacuum valves. The vacuum countdown will start
from atmospheric pressure 00000. Depending on the size of the system, the lines on the LCD
display will disappear one by one. Once all
lines have disappeared, the numerical reading will appear on the LCD. The numbers descend
from 25000 MICRONS or corresponding units.
4
HIGH
= CLOSED
HIGH
Monitoring
= OPEN
HIGH
VACUUM
CONFIGURATION
Vacuuming
HIGH
Charging
VACUUM CABLE
PUMP
TO RECOVERY/
VACUUM OR
TO HIGH SIDE
REFRIGERANT
(RED)
SUPPLY (YELLOW)
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VAC
LOW
LOW
LOW
VAC
LOW
LOW
LOW
VAC
LOW
VAC
VACUUM SELECT
LOW HIGH
REF
VAC
REF
HIGH
HIGH
DIAGNOSTIC
Vacuuming
CONFIGURATION
HIGH
Monitoring
REF
REF
HIGH
HIGH
CHARGING
CONFIGURATION
Vacuuming
Charging
REF
HIGH
Charging
TO VACUUM PUMP
(BLACK)
LOW
LOW