Dometic CoolMatic HDC
Official technical documentation and workshop diagnostics for CoolMatic HDC.
Technical Specifications
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 connection cable between battery and electronics, defective main switch, or blown auxiliary inline fuse. | Establish connection, replace main switch, or replace inline fuse. | DIY Safe |
N/A | Compressor does not run with battery voltage too low (UKL <= UTIL) Possible Cause: Low battery voltage, loose cable connection, poor connection (corrosion), low battery capacity, or cable cross-section too small. | Charge battery, fix/clean connection, replace battery, or replace cable with correct cross-section according to manual charts. | DIY Safe |
N/A | Compressor does not run despite sufficient voltage (UKL >= UTIL) Possible Cause: Ambient temperature too high, insufficient ventilation, dirty condenser, defective fan, or electrical interruption inside the compressor. | Relocate refrigerator, clean condenser, replace fan, or replace compressor. | DIY Check / Tech Fallback |
N/A | Compressor runs constantly (Inner temperature too cold on setting '1') Possible Cause: Thermostat sensor has no contact with the evaporator, or short circuit in thermostat line / defective thermostat. | Fasten sensor or replace thermostat. | DIY Check / Tech Fallback |
N/A | Cooling capacity reduced, inner temperature rises (Compressor runs long/constantly) Possible Cause: Frost layer forming on evaporator, ambient temperature too high, insufficient ventilation, dirty condenser, or defective fan. | Defrost evaporator, relocate refrigerator, clean condenser, or replace fan. | DIY Check / Tech Fallback |
N/A | Water inside or under the refrigerator Possible Cause: Water drainage channel is clogged, food items blocking the drain collector, or too much water in the air separator. | Clean drain using the provided cleaning tool, rearrange food items so they do not touch the back wall, and clean the air separator. | DIY Safe |
N/A | Unusual noises (Loud humming) Possible Cause: A component of the cooling circuit cannot swing freely (touching the wall) or foreign object jammed between cooling unit and wall. | Carefully bend component away or remove foreign object. | 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.