Carrier Container Refrigeration Unit 69NT40-511-8

Turn unit off and disconnect main power.

Disconnect water pressure switch tubing by loosening the two flare nuts.

Install one-quarter inch flare cap on water-cooled condenser inlet tube.

Ensure availability of materials

Cleaning and De-scaling Procedure

Drain and flush the water circuit of the condenser coil.

Clean water tubes with Oakite No. 22 to remove mud and slime.

Prepare an ice-water bath at 0°C (32°F)

Ensure the ohmmeter is calibrated and ready for use

Sensor Placement and Initial Check

Place the sensor in the ice-water bath

Check air temperature/data readout on the control panel

Is the air temperature/data readout 0°C (32°F)?

Select the method for temperature stabilization

Set the unit 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

Enter the temperature indicated by the resistance thermometer

Is the temperature difference more than 0.6°C (1°F) when compressor cycles off?

Operate the unit in cooling mode for at least 20 minutes

Check the front oil sight glass for foaming after 20 minutes of operation

If oil is foaming excessively, check the refrigerant system for flood-back of liquid refrigerant

Turn unit off to check the oil level

Is the oil level between the bottom to one-eighth level of the sight glass?

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 where 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