ServiceNomad RV · Knowledge
Norcold RV Refrigerator Not Cooling
When your Norcold absorption refrigerator runs but fails to cool, the issue is almost always related to the heat exchange cycle—either insufficient heat is reaching the boiler, airflow around the cooling fins is blocked, or the refrigerant mixture inside the sealed system has failed. Unlike residential compressor fridges, absorption refrigerators have no moving parts and rely on precise heat and airflow management to function.
How Absorption Cooling Works
Norcold absorption refrigerators use heat (from propane flame or electric heating element) to boil an ammonia-water solution. The ammonia vapor rises through the cooling unit, condenses back to liquid while releasing heat, and then re-evaporates inside the food compartment to absorb heat. This cycle requires the boiler to reach a specific temperature and for the condenser coils on the exterior to dissipate heat effectively. If any part of this cycle is disrupted—not enough heat at the boiler, blocked airflow preventing heat dissipation, or refrigerant contamination—the fridge will run but produce no cooling.
Blocked Cooling Fins and Airflow
The exterior cooling fins (visible from outside the RV behind a vent cover) must have unobstructed airflow to dissipate the heat generated during the absorption cycle. If these fins are caked with dust, blocked by wasp nests, or surrounded by nearby items that restrict airflow, the cooling unit cannot reject heat and the cycle fails. The fridge will run warm or hot even though it's operating. A technician will remove the exterior vent cover and inspect the cooling fins. Cleaning is done with compressed air or a soft brush—never use high-pressure water, which can bend the delicate fins. In hot climates, adding external fans to force airflow across the fins can significantly improve cooling performance.
Propane Flame Quality and Electric Element Function
When running on propane, the flame should be steady, blue, and centered on the boiler flue. A yellow, flickering, or weak flame indicates incomplete combustion—often caused by a clogged burner orifice, spider webs in the flue, or improper propane pressure. This weak flame cannot generate enough heat to drive the cooling cycle. When running on electric mode (120V AC), the heating element must reach full temperature. If the element is partially burned out or if voltage is low, the boiler won't get hot enough. A technician can test element resistance with a multimeter and verify proper voltage at the element terminals.
Cooling Unit Failure (Sealed System)
If airflow is good, heat source is functioning, and the fridge still won't cool, the sealed cooling unit may have failed. This happens when the internal refrigerant mixture becomes contaminated with hydrogen or when a leak allows ammonia to escape. Once the sealed system fails, no amount of cleaning or heat adjustment will restore cooling—the entire cooling unit must be replaced. Cooling unit replacement is expensive (often $800-1500 in parts alone) and labor-intensive. Some owners opt to install an aftermarket compressor-based cooling system instead, which is more reliable and efficient in hot climates.
⚠️ Safety Notes
- Never operate the refrigerator on propane mode while driving or refueling—this is a fire hazard.
- If you smell ammonia (sharp, pungent odor), turn off the refrigerator immediately and ventilate—ammonia leaks can be dangerous in enclosed spaces.
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