Mastercool 90413 4-way Valve Digital Manifold - Manual (Page 5)

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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.
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LOW
VAC REF
HIGH
VACUUM CABLE
TO LOW SIDE
(BLUE)
TO HIGH SIDE
(RED)
TO VACUUM PUMP
(BLACK)
CONNECT TO
SYSTEM OR
PUMP
FIG. B
TO RECOVERY/
VACUUM OR
REFRIGERANT
SUPPLY (YELLOW)
• 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.
NOTE: The unit will shut down after 15 minutes automatically. Press the POWER button
again. Allow 30-45 seconds for initializing and the correct vacuum reading to appear.
Once the target vacuum is reached, close the vacuum valve and disconnect the vacuum
gauge port from the system. Press the
POWER button to turn the unit off. (If pressure,
temperature or deep vacuum is being used for an extended period of time turn the
unit off and turn back on again when reading is required.)
WARNING!! Never stop the vacuum pump unless the vacuum gauge
is disconnected. Failure to do so may cause oil to enter the sensor
chamber.
IMPORTANT: When checking a system for leaks under high vacuum (less than 1000
microns), connect the vacuum gauge directly to the system. If additional connec-
tions are required use copper tubing (do not use rubber hoses) and high vacuum
shut-off valves. Standard hoses and manifold gauge set shut-off valves may have
a small amount of leakage under high vacuum. When initiating a high vacuum test,
the vacuum gauge reading may “drift” higher until the system has equalized. After
this short stabilization period (5 minutes) the vacuum reading should hold steady. An
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