Compressor does not run (UKL = 0 V)

Possible cause: Interruption in the connection between battery and electronics, faulty main switch, or blown additional supply line fuse. Establish a secure connection, replace the main switch, or replace the supply line fuse

Compressor does not run (UKL <= UOFF / Battery voltage too low)

Possible cause: Loose cable connection, poor contact (corrosion), low battery capacity, or too small cable cross section. Clean/secure connections, charge or replace the battery, or replace the cable with a correct cross-section according to the manual gauge chart

Compressor does not run (Ambient temperature too low)

Possible cause: Usage when ambient temperature is below +16 °C. Only operate the freezer at an ambient temperature of more than +16 °C

Compressor runs constantly or for a long time

Possible cause: Thermostat sensor has no contact on the vaporiser, faulty thermostat, iced-over vaporiser, or insufficient ventilation. Secure the sensor, replace the thermostat, defrost the vaporiser, or move the freezer to improve ventilation and clean the condenser

Poor cooling, interior temperature increases

Possible cause: Condenser is dirty, defective fan, or exhausted battery capacity. Clean the condenser, replace the fan, or charge the battery

Unusual noises (Loud humming)

Possible cause: A component of the refrigerant circuit cannot move freely and touches the wall, or a foreign body is jammed between the cooling unit and the wall. Carefully bend the component away from the obstruction or remove the foreign body

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Dometic • Freezer / Refrigerator

Dometic CoolMatic CRF-50

Q: Compressor does not run (UKL <= UOFF / Battery voltage too low)

Possible cause: Loose cable connection, poor contact (corrosion), low battery capacity, or too small cable cross section. Clean/secure connections, charge or replace the battery, or replace the cable with a correct cross-section according to the manual gauge chart

Q: Compressor does not run (Ambient temperature too low)

Possible cause: Usage when ambient temperature is below +16 °C. Only operate the freezer at an ambient temperature of more than +16 °C

Q: Compressor runs constantly or for a long time

Possible cause: Thermostat sensor has no contact on the vaporiser, faulty thermostat, iced-over vaporiser, or insufficient ventilation. Secure the sensor, replace the thermostat, defrost the vaporiser, or move the freezer to improve ventilation and clean the condenser

Q: Poor cooling, interior temperature increases

Possible cause: Condenser is dirty, defective fan, or exhausted battery capacity. Clean the condenser, replace the fan, or charge the battery

Q: Unusual noises (Loud humming)

Possible cause: A component of the refrigerant circuit cannot move freely and touches the wall, or a foreign body is jammed between the cooling unit and the wall. Carefully bend the component away from the obstruction or remove the foreign body

Official technical documentation and workshop diagnostics for CoolMatic CRF-50.

Technical Specifications

Electrical12 V DC or 24 V DC, Average power consumption: 45 W, Cut-off voltage: 10.4 V (12 V) / 22.8 V (24 V), Cut-in voltage: 11.7 V (12 V) / 24.2 V (24 V), Minimum supply line fuse: 15 A (at 12 V) / 7.5 A (at 24 V)

Gas Or PressureRefrigerant circuit contains R134a

Capacities DimensionsCapacity: 47 l (approx. 50 l), Dimensions (WxHxD): 448 x 527 x 543 mm, Weight: 25 kg, Constant inclination: max. 30°, Maximum relative air humidity: 90%, Ambient operating temperature range: +18 °C to +32 °C (Compressor starts at > +16 °C)

Master Troubleshooting & Diagnostics Matrix

Error Code / Indicator	Symptom / Meaning	Step-by-Step DIY Fix	Suggested Actions
`N/A`	Compressor does not run (UKL = 0 V) Possible Cause: Interruption in the connection between battery and electronics, faulty main switch, or blown additional supply line fuse	Establish a secure connection, replace the main switch, or replace the supply line fuse	DIY Safe
`N/A`	Compressor does not run (UKL <= UOFF / Battery voltage too low) Possible Cause: Loose cable connection, poor contact (corrosion), low battery capacity, or too small cable cross section	Clean/secure connections, charge or replace the battery, or replace the cable with a correct cross-section according to the manual gauge chart	DIY Safe
`N/A`	Compressor does not run (Ambient temperature too low) Possible Cause: Usage when ambient temperature is below +16 °C	Only operate the freezer at an ambient temperature of more than +16 °C	DIY Safe
`N/A`	Compressor runs constantly or for a long time Possible Cause: Thermostat sensor has no contact on the vaporiser, faulty thermostat, iced-over vaporiser, or insufficient ventilation	Secure the sensor, replace the thermostat, defrost the vaporiser, or move the freezer to improve ventilation and clean the condenser	DIY Check / Tech Fallback
`N/A`	Poor cooling, interior temperature increases Possible Cause: Condenser is dirty, defective fan, or exhausted battery capacity	Clean the condenser, replace the fan, or charge the battery	DIY Check / Tech Fallback
`N/A`	Unusual noises (Loud humming) Possible Cause: A component of the refrigerant circuit cannot move freely and touches the wall, or a foreign body is jammed between the cooling unit and the wall	Carefully bend the component away from the obstruction or remove the foreign body	DIY Safe

Frequently Asked Questions

Q: What does climate class of SN (Sub Normal) mean?

The climate class SN (Sub Normal) defines the intended ambient temperature range for the absorption fridge's optimal operation.

Q: What’s the cooling performance in warmer ambient temperatures?

Cooling performance for absorption fridges is affected by warmer ambient temperatures. Ensure proper ventilation around the unit as detailed in the manual to maintain performance.

Q: How to operate an RMxxxx with a solar panel?

To operate an RMxxxx series absorption fridge with a solar panel, ensure the solar system provides adequate 12V DC power or sufficient battery storage to handle the power requirements, particularly when running on DC mode.

Q: My RMxxxx needs to be replaced. What would be an alternative?

When replacing an RMxxxx series refrigerator, look for current Dometic absorption or compressor models matching the physical dimensions and energy source requirements of your motorhome cutout.

Q: The refrigerator does not work In AC power mode?

Check if the vehicle is properly connected to the AC mains supply, verify that the AC fuse in the motorhome is intact, and ensure the refrigerator is switched on to AC mode on the control panel.

Q: The refrigerator does not work In DC power mode?

DC mode (12V) typically only works while the vehicle engine is running and the alternator is supplying power, preventing the vehicle starter battery from draining. Check the 12V DC fuses, vehicle ignition connection, and input voltage at the refrigerator terminals.

Q: The refrigerator does not work In GAS mode?

Ensure the gas cylinder valve is open, the main gas shut-off valves in the motorhome are open, and there is no air trapped in the gas line (try igniting another gas appliance first). Check if the igniter is sparking and that the burner is clean.

Q: In automatic mode: The refrigerator is being operated with gas although it is connected to The AC power supply?

In automatic energy selection mode, if the AC voltage is outside the acceptable tolerance range or unstable, the control system automatically switches to gas mode as a safety fallback. Check the AC supply voltage and connections.

Q: The refrigerator is not cooling adequately?

Verify that ventilation grilles are not blocked, check that the thermostat is set correctly, ensure the door seals tightly, do not overpack the interior restricting airflow, and verify that the selected energy source (AC, DC, or Gas) is actively functioning.

Q: WARNING type fault messages

WARNING type fault messages indicate a non-critical operational issue or prompt. Consult the user manual for the specific warning code displayed on the 10-series control panel to take corrective action.

Q: ERROR type fault messages

ERROR type fault messages indicate a critical system failure that stops the refrigerator from functioning safely on the current energy source. Check the specific error code on the display, troubleshoot the underlying power, gas, or ventilation issue, or contact customer service.