MasterCool R134a Operating Instructions

WARNING

• WEAR GOGGLES!!
• AVOID CONTACT WITH REFRIGERANT
• DO NOT VENT REFRIGERANT INTO
ATMOSPHERE

PRE-SERVICE INSTRUCTIONS

1. Close both valves on the manifold gauge set
by turning the high and low knobs clockwise.
2. The gauges are correctly calibrated at the
factory before shipment. If calibration is
required, insert a straight blade screwdriver
into the adjusting screw on the gauge face.
3. Attach the high and low couplers to the
male end of the red and blue hoses. If using
manual couplers, open the plunger by
turning the knob counter-clockwise prior to
connection to the system. If quick couplers
are used, pull the sleeves up to unlock
position before attaching to an A/C system.
NOTE: Attach 12 mm-m x 14 mm-f R1234yf
adapters (fig. II) to R1234yf couplers (fig. Q,R
or CC, DD) before connecting to the red and
blue hose.
4. Connect the red hose to the high side port and the blue hose to the low side port on the manifold gauge.

TROUBLESHOOTING TIPS

• Low side and high side pressure are low. Usually indicates a low charge.
• Low side pressure is low and high side pressure is high. Usually indicates a blockage in the system.(i.e.
expansion of valve or orifice tube.)
• Low side pressure is high and high side pressure is low. When accompanied by a vibrating gauge
needle, usually indicates faulty reed valves in compressor.
• Low side and high side pressures are high. Usually indicates an over charged system.

TESTING AND CHARGING

To properly diagnose the problem in the A/C system, first check the system's overall performance. This
includes testing the system's pressure and refrigerant flow. These conditions can be checked with the
manifold gauge set.
NOTE: Be sure that the hand valves on the manifold gauge set are in the closed position. Always
wear gloves and safety goggles when working with refrigerant.
1. Remove the protective caps from the system ports. Check for leaks at the ports.
2. Connect the low side service hose (blue) to the suction side of the compressor. Connect the high side
R134a/R1234yf MANIFOLD GAUGE SET

OPERATING INSTRUCTIONS

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