ServiceNomad RV · Knowledge
Norcold NO CO Error Code
The NO CO error on Norcold refrigerators indicates 'No Cooling'—the control board has detected that the refrigerator is not cooling properly despite running. This error typically appears after the fridge has been operating for some time without achieving proper temperatures, suggesting issues with the cooling system, power supply, or temperature sensors. Understanding what triggers NO CO helps you determine whether the issue is a failed cooling unit, control board fault, or environmental problem.
What the NO CO Error Indicates
Norcold's NO CO error is triggered when the control board detects that the refrigerator has been running for an extended period (typically 8-24 hours depending on model) without reaching proper operating temperatures. The board monitors thermistor readings and compares them to expected values. If the fridge remains too warm despite continuous operation, the board assumes a cooling failure and displays NO CO. This error is designed to alert you to a serious problem before food spoils. It does not pinpoint the exact cause—it simply indicates the end result (no cooling). Further diagnosis is needed to determine whether the issue is with the cooling unit, control board, power supply, or installation environment.
Cooling Unit and Absorption System Failures
Norcold refrigerators use absorption cooling technology, which relies on a sealed ammonia/hydrogen system to transfer heat. If the cooling unit develops a leak or becomes contaminated (from incorrect installation angle, overheating, or age), it loses effectiveness and eventually fails completely. A failed cooling unit cannot be repaired—it must be replaced, which is often cost-prohibitive compared to replacing the entire fridge. A technician will inspect the cooling unit for signs of yellow staining (indicating ammonia leakage), check that the unit is properly leveled (RVs must be within 3-6 degrees of level for absorption fridges to work), and verify the burner or heating element is operating correctly. They'll also check that the cooling fins and coils are not blocked by frost or debris.
Airflow and Ventilation Issues
Absorption refrigerators require proper airflow to dissipate heat from the condenser. If the exterior vents are blocked (by insect nests, debris, or poor installation), heat buildup prevents effective cooling and can trigger NO CO errors. Inadequate ventilation can also cause the cooling unit to overheat and fail prematurely. A technician will inspect the lower intake vent and upper exhaust vent for obstructions, verify the cooling fans (if equipped) are operating, and check that there's adequate clearance around the fridge for proper air circulation. In some cases, adding a fan to the vent system can improve cooling performance and prevent NO CO errors.
Power Supply and Control Board Issues
Norcold fridges operate on propane, 120V AC, or 12V DC depending on mode selection. If the selected power source is not delivering adequate energy, the fridge will run but won't cool properly. For example, low propane pressure, weak 12V DC voltage, or insufficient 120V AC voltage can all cause poor cooling and eventual NO CO errors. A technician will test voltage at the fridge (should be 11.5-14.5V DC or 115-125V AC depending on mode), verify propane pressure is correct (11 inches water column), and inspect the control board for faults. If the board is misreading temperatures or failing to properly control the cooling system, it may need replacement.
⚠️ Safety Notes
- If you smell ammonia (strong, pungent odor) near the fridge, shut it down immediately—this indicates a cooling unit leak and potential health hazard.
💡 Prevention Tips
- Keep exterior fridge vents clear of debris and inspect them annually for insect nests.
- Ensure your RV is reasonably level when parked to allow the absorption cooling unit to function properly.
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