Troubleshooting; Troubleshooting - Test A, Protection Cut-Out; Troubleshooting - Test B, Fan Over Current Cut-Out; Troubleshooting - Test C, Motor Start Error - Norcold DC558 Service Manual

Troubleshooting

Troubleshooting - Test A, Protection Cut-Out

For proper operation, the unit's DC supply voltage:
At 12 VDC nominal input must be:
• Above 12.2 VDC to start.
• Remain between 10.9 VDC to 17 VDC to continue opera-
tion.
At 24 VDC nominal input must be:
• Above 25.2 VDC to start.
• Remain between 23.8 VDC to 31.5 VDC to continue op-
eration.
1. Perform the "Diagnostic Pre-checks".
2. Verify that the supply voltage is correct:
• Remove the unit from its enclosure, leaving the DC supply
connected.
• Inspect the fuse on the positive DC lead connected to the
module terminal "+".
Is the fuse good?
• Yes: Go to next step.
• No: Replace the fuse, test the unit.
3. With the thermostat 6) in the "OFF" position, check the voltage
at the DC connector. Is the voltage between 12.2 VDC and 17
VDC (12 VDC nominal input) or between 25.2 VDC and 31.5
VDC (24 VDC nominal input)?
• Yes: Go to next step.
• No: Repair DC supply voltage, test unit.
4. With the thermostat 6) in the 5 position, check the voltage at the
DC connector. Is the voltage between 10.9 VDC and 17 VDC
(12 VDC nominal input) or between 23.8 VDC and 31.5 VDC
(24 VDC nominal input)?
• Yes: Go to next step.
• No: Repair DC supply voltage, test unit.
5. With the thermostat 6) in the 5 position, check the voltage at the
control module's (+) terminal. Is the voltage between 10.9 VDC
and 17 VDC (12 VDC nominal input) or between 23.8 VDC and
31.5 VDC (24 VDC nominal input)?
• Yes: Replace control module, test unit.
• No: Repair unit power cord, test unit.
www.norcold.com

Troubleshooting - Test B, Fan Over Current Cut-Out

1. Perform the "Diagnostic Pre-checks".
2. Remove the unit from its enclosure leaving the DC power sup-
ply connected.
3. With the thermostat 6) in the 5 position, check that the condens-
er fan is working.
Is the fan working?
• Yes: Replace cooling unit.
• No: Go to next step.
4. Check for DC power at the control module's "+" terminal.
Is the voltage correct?
• Yes: The fan has failed. Replace cooling unit.
• No: Replace control module.

Troubleshooting - Test C, Motor Start Error

1. Perform the "Diagnostic Pre-checks".
2. Remove the unit from its enclosure leaving the DC power sup-
ply connected.
3. Turn unit OFF for minimum of three (3) minutes to allow internal
system pressures to equalize.
4. Turn the unit ON.
Did code 3 return?
• Yes: Replace cooling unit.
• No: Repair complete.
11
SERVICE MANUAL