Carrier Container Refrigeration Unit 69NT40-511-17

Filter-Drier Replacement Process

Evacuate the unit as per section 6.5

Open the manual liquid line valve

Turn unit start-stop switch OFF

Frontseat both suction and discharge service valves to isolate compressor

Remove the refrigerant from the compressor

Disconnect wiring from defective switch

Remove the high pressure switch by turning counterclockwise

Verify switch settings before installation

Select the method for temperature stabilization

Set the unit's set point to 0°C (32°F)

Allow the unit to pull down to 0°C (32°F)

Enter the number of compressor ON-OFF cycles observed

Record the temperature indicated by the thermometer when the compressor cycles off

Does the temperature differ from 0°C (32°F) by more than 0.6°C (1°F)?

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

Ensure no mixing of refrigerants with air for leak testing.

Avoid exposing pressurized, air-rich mixtures of refrigerants to ignition sources.

Use R-134a electronic leak detector for finding leaks.

Use soapsuds for locating large leaks only.

Charge the system with refrigerant to build up pressure between 2.1 to 3.5 kg/cm² (30 to 50 psig).