Carrier Container Refrigeration Unit 69NT40-511-10

Checking the Refrigerant Charge

Set the controller set point to -25°C (-13°F)

Ensure the suction modulation valve is fully open

Connect the gauge manifold to the compressor service valves

Is the unit equipped with a receiver?

Partially block the condenser coil inlet air

Raise compressor discharge pressure to approximately 12 kg/cm² (175 psig)

Is the refrigerant level between the sight glasses?

Open door and remove chart nut and platen.

Push voltage indicator test switch. Is the voltage indicator in the red or white zone?

Replace battery if voltage indicator points to the red or white zone.

Place recorder bulb in ice bath for 10 minutes.

Rotate the chart by hand and check the stylus indicated temperature.

Is adjustment required for the stylus?

Ensure power to the unit is OFF and power plug disconnected

Disconnect the suction modulation valve coil wires by unplugging the connector

Test each lead’s resistance to ground using a digital ohmmeter

Is there a ground short present?

Inspect the length of wiring for damaged or exposed wires and replace if necessary

Check coil’s resistance using a digital ohmmeter set to low range

Is the coil’s resistance below five ohms?

Plug in the connector for the modulation valve

Turn unit power OFF and disconnect power supply

Remove and save any cover over wiring and probe holder, if present

Cut cable 5 cm (2 inches) from shoulder of defective sensor and discard the defective probe only

Save cap and grommet assembly for reuse on the replacement probe

Cut one wire of existing cable 41 mm (1-5/8 inches) shorter than the other wire

Cut one replacement sensor wire (opposite color) back 41 mm (1-5/8 inches)

Remove the protective guard from lower section of the unit.

Remove all refrigerant using a refrigerant recovery system.

Locate the compressor junction box and remove wiring.

Disconnect wiring from compressor terminals and remove compressor junction box.

Remove bolts from service valve flanges.

Remove compressor plate mounting bolts.

Remove compressor and mounting plate.

Remove high pressure switch (HPS) from compressor and check operation of switch.