Truma CP plus
Official technical documentation and workshop diagnostics for CP plus.
Technical Specifications
Operating Voltage8 V – 16.5 V DC
Power Consumptionmax. 65 mA (100% background lighting) / 6.5 mA – 10 mA (stand-by) / 3 mA (Off)
Dimensions Cutout92 x 103 x 40 mm
Master Troubleshooting & Diagnostics Matrix
| Error Code / Indicator | Symptom / Meaning | Step-by-Step DIY Fix | Suggested Actions |
|---|---|---|---|
W 17 H | Warning Water overheat condition (woc) Possible Cause: Water temperature inside the container has exceeded normal limits | Switch heater off and allow it to cool. Fill the water container with water. | DIY Safe |
W 18 H | Warning Air overheat condition Possible Cause: Not all warm air ducts are connected, warm air outlets are blocked, or circulated air intake is blocked | Make sure that all warm air ducts are connected to the heater, check whether warm air ducts are damaged or kinked, remove the blockage in the circulated air intake and ensure that the installation space is sufficiently ventilated. | DIY Safe |
W 402 H | Warning Air overheat condition Possible Cause: Warm air ducts disconnected, blocked, or circulated air intake obstructed | Make sure that all warm air ducts are connected to the heater, check whether warm air ducts are damaged or kinked, remove the blockage in the circulated air intake and ensure that the installation space is sufficiently ventilated. | DIY Safe |
W 24 H | Imminent low voltage / battery voltage too low < 10.4 V Possible Cause: Supply voltage has dropped below acceptable thresholds | Check the function with the motor running, check the power supply unit or other batteries. Charge battery and check contacts, replace old battery. | DIY Safe |
E 29 H | Power consumption of the FrostControl heating element too high Possible Cause: Electrical fault or short circuit in the FrostControl heating element | Must be replaced by an authorized service agent. | Professional Intervention Required |
W 42 H | Window switch detects open window Possible Cause: Window above cowl is open while heater is operating | Close window above cowl. | DIY Safe |
W 412 H | Window switch detects open window Possible Cause: Window above cowl is open | Close window above cowl. | DIY Safe |
E 43 H | 12 V power supply faulty (overvoltage) Possible Cause: Excessive voltage supplied at the appliance 12 V input | Check the 12 V power supply at the appliance input under load; to test, disconnect the power supply unit and the solar system from the on-board power supply. | DIY Safe |
W 301 H | 12 V power supply faulty (overvoltage) Possible Cause: Voltage exceeds safe operating limits | Check the 12 V power supply at the appliance input; to test, disconnect the power supply unit and the solar system from the on-board power supply. | DIY Safe |
E 540 H | 12 V power supply faulty (overvoltage) Possible Cause: Input voltage too high | Ensure 12 V power supply under load at appliance input / check for AC voltage components (disconnect power supply unit and solar system from on-board power supply). | DIY Safe |
W 45 H | 230 V power supply faulty Possible Cause: Mains supply issue or blown 230 V fuse or overheating protection triggered | Check the 230 V power supply at the appliance input. Have an expert check the 230 V fuse and replace it if necessary. Reset the 230 V overheating protection (see Combi operating instructions). | DIY Check / Tech Fallback |
W 407 H | 230 V power supply faulty Possible Cause: Mains voltage missing or internal 230 V fuse blown | Check the 230 V power supply at the appliance input. Have an expert check the 230 V 10 AF fuse and replace it if necessary. | DIY Check / Tech Fallback |
W 164 H | 230 V power supply faulty Possible Cause: Mains supply fault or blown internal T10AH fuse | Check the 230 V power supply at the appliance input. Reset the 230 V overheating protection. Have an expert check the 230 V T10AH fuse and have it replaced if necessary. | DIY Check / Tech Fallback |
E 111 H | Fault in the electronics Possible Cause: Internal electronic error or unstable 12 V supply input under load | Check the 12 V power supply at the appliance input under load; to test, disconnect the power supply unit and the solar system from the on-board power supply. If the issue remains unresolved, contact an authorized service agent. | DIY Check / Tech Fallback |
E 112 H | Flame out or not detected, Flame unstable during operation, Gas supply interrupted Possible Cause: Interruption in gas supply or incorrect operating pressure | Check that the gas supply has the correct operating pressure. | DIY Safe |
E 122 H | Lack of fuel due to low tank level, tank is empty and / or vehicle is on a slope Possible Cause: Fuel tank empty or vehicle tilted preventing fuel pickup | Fill tank with fuel and then fill the fuel line (see operating instructions / initial start-up). | DIY Safe |
W 255 H | Heater has no 12 V power supply or no connection between heater and control panel Possible Cause: Power cable disconnected or control panel bus communication fault | Check the 12 V power supply at the appliance input; to test, disconnect the power supply unit and the solar system from the on-board power supply. Check the control panel cable and make sure there is connection between the heater and the control panel. | DIY Safe |
W 302 H | 12 V power supply faulty (low voltage) Possible Cause: Battery voltage has dropped too low | Charge battery and check contacts, replace old battery. | DIY Safe |
W 160 H | 12 V power supply faulty (low voltage) Possible Cause: Low battery voltage or high resistance on supply line | Ensure 12 V power supply under load at appliance input, charge battery and check contacts, replace old battery, or switch off high-consumption appliances. | DIY Safe |
E 541 H | 12 V power supply faulty (low voltage) Possible Cause: Input voltage too low | Ensure 12 V power supply under load at appliance input, charge battery and check contacts, replace old battery. | DIY Safe |
W 303 H | Risk of low voltage. Battery voltage too low < 10.4 V Possible Cause: Battery state of charge is critically low | Check the function with the motor running, check the power supply unit or other batteries. Charge battery and check contacts, replace old battery. | DIY Safe |
W 401 H | Hot water mode with empty water container Possible Cause: Water heating activated while container is empty | Switch heater off and allow it to cool. Fill the water container with water. | DIY Safe |
W 408 H | Gas supply interrupted in mixed mode Possible Cause: Gas pressure drop or empty gas bottle while operating in mixed mode | Check that the gas supply has the correct operating pressure. Start the heater in gas mode, acknowledge the fault and switch to mixed mode. | DIY Safe |
E 507 H | Gas supply interrupted Possible Cause: Gas supply failure or incorrect pressure | Check that the gas supply has the correct operating pressure. | DIY Safe |
E 607 H | Maximum number of fault resets reached / heater is blocked Possible Cause: More than 4 resets attempted within 15 minutes | Wait 15 minutes and reset fault. | DIY Safe |
E 621 H | Room temperature sensor or cable faulty Possible Cause: Damaged room temperature sensor wire or loose plug connection | Check the cable for the room temperature sensor and plug connections. Replace the room temperature sensor if faulty. | DIY Safe |
E 624 H | FrostControl heating element has a short circuit Possible Cause: Electrical short circuit in FrostControl heating element | Must be replaced by an authorized service agent. | Professional Intervention Required |
E 132 H | FrostControl heating element has a short circuit Possible Cause: Short circuit detected in FrostControl heating element circuit | Ensure 12 V power supply under load at appliance input / check for AC voltage components (disconnect power supply unit and solar system from on-board power supply). If the issue persists, contact an authorized service agent. | DIY Check / Tech Fallback |
E 632 H | 230 V overheating protection has triggered Possible Cause: Mains heating element overheated | Reset the 230 V overheating protection (see Combi operating instructions). | DIY Safe |
E 131 H | No connection between heater and control panel Possible Cause: Communication bus cable disconnected or damaged | Connect the heater and the control panel securely. | DIY Safe |
W 150 H | Warm air temperature exceeded Possible Cause: Blocked air ducts or restricted circulated air intake | Make sure that all warm air ducts are connected to the heater, check whether the warm air ducts are damaged or kinked, remove the blockage in the circulated air intake and ensure that the installation space is sufficiently ventilated. | DIY Safe |
W 151 H | Water temperature exceeded in heater mode Possible Cause: Empty water container or restricted warm air/circulated air flow | Switch heater off and allow to cool, fill water container with water. Make sure that all warm air ducts are connected and clear of blockages. | DIY Safe |
E 152 H | Water temperature exceeded in hot water mode Possible Cause: Water container empty during hot water operation | Switch heater off and allow to cool, fill water container with water. | DIY Safe |
E 162 H | Window above cowl open (window switch) Possible Cause: Safety switch triggered by open window near exhaust cowl | Close window above cowl. | DIY Safe |
W 163 H | One of the temperature switches has opened Possible Cause: Appliance overheated due to restricted airflow | Allow the heater to cool. If this occurs frequently, contact an authorized service agent. | Professional Intervention Required |
W 170 H | Imminent low voltage < 11.5 V Possible Cause: Supply voltage dropping toward threshold | Ensure 12 V power supply under load at appliance input, charge battery and check contacts, replace old battery. | DIY Safe |
W 423 H | Initial filling required (filling function at initial start-up) Possible Cause: Boiler system unprimed during initial start-up | Activate initial filling by setting a heating request with temperature settings 30 °C. | DIY Safe |
W 424 H | Initial filling active Possible Cause: Boiler is currently running initial priming cycle | Do not switch the heater off or interrupt the power supply during initial filling. | DIY Safe |
E 560 H | Heater will not start (locked after fifth error acknowledgment) Possible Cause: Repeated failed start attempts resulting in lockout | Check the fuel supply at the appliance input. If the issue remains unresolved, contact an authorized service agent. | DIY Check / Tech Fallback |
E 561 H | Cannot restart heater. Maximum number of start attempts reached – operating lock is activated Possible Cause: Operating lock activated due to consecutive failed start attempts | Contact an authorized service agent. | Professional Intervention Required |
E 565 H | Heater will not start, flame repeatedly not detected Possible Cause: Fuel delivery issue or air in fuel lines | Check the fuel supply at the appliance input. | DIY Safe |
E 8 A | IR receiver unplugged or cable broken Possible Cause: Infrared receiver connection disconnected or damaged | Check the connection of the IR receiver. | DIY Safe |
E 17 A | Voltage dip at 230 V power supply Possible Cause: Mains supply voltage drop affecting air conditioning system | Check 230 V power supply. | DIY Safe |