The Truma W407H code is a specific warning displayed on the CP+ control panel for a Truma combi boiler, indicating an interruption in the 240V electrical supply to the caravan or motorhome while the boiler is set to operate on electric mode.
Understanding the Truma W407H Warning Code
This code specifically highlights an issue with the mains electricity connection to your leisure vehicle when your Truma combi heating and hot water system is attempting to run on its electric heating element. It typically appears prominently on the Truma CP+ digital control panel, alerting you to a power supply problem affecting the boiler's electric operation.
Common Causes of the W407H Code
The primary reason this warning arises is when the 240V mains power supply to your caravan or motorhome is unexpectedly disconnected or interrupted while the Truma combi boiler is configured to use its electric heating function.
Typical scenarios that can trigger the W407H code include:
- Disconnected Shore Power: The main 240V hook-up cable to your caravan or motorhome is unplugged from the supply pedestal or the vehicle, often inadvertently.
- Tripped Circuit Breaker: A circuit breaker, either at the campsite hook-up point or within your vehicle's consumer unit, has tripped due to an overload or fault, cutting off the 240V supply.
- Power Outage: A general electricity outage at the campsite or home location where your vehicle is connected.
- Faulty Connection: A loose or damaged 240V connection or cable preventing a stable power supply to the vehicle.
| Warning Code | Description | Primary Cause |
|---|---|---|
| W407H | Interrupted 240V electric supply to Truma combi boiler while in electric mode. | 240V mains power to the caravan/motorhome disconnected or unstable when the boiler is set to use electric. |
Impact and Solutions for W407H
When the W407H code is displayed, your Truma combi boiler will likely cease operation on its electric heating element. While it might automatically attempt to switch to gas operation if available and configured, it will not provide heat or hot water via electricity until the supply issue is resolved.
To address the W407H warning and restore electric operation of your Truma combi boiler, follow these troubleshooting steps:
- Check 240V Connection: Ensure the main hook-up cable is securely connected at both the leisure vehicle inlet and the external supply pedestal or home socket.
- Inspect Circuit Breakers: Verify that all relevant circuit breakers, both on the external supply pillar (if applicable) and within your caravan or motorhome's internal consumer unit, are in the "on" position. Reset any tripped breakers by switching them fully off, then back on.
- Confirm Power Supply: If on a campsite, check if other appliances are receiving power or if there's a general site power issue. You might also ask a neighbor if they are experiencing similar issues.
- Verify Boiler Settings: Confirm that your Truma combi boiler is correctly configured for electric operation (e.g., selecting 850W or 1700W on the control panel) and not attempting to draw power it isn't receiving.
- Restart System: Once the 240V supply is confirmed and restored, you may need to reset or restart your Truma CP+ panel or the entire boiler system to clear the warning code. This can often be done by cycling the power to the Truma control panel or holding down the reset button if available. Consult your specific Truma user manual for precise reset procedures for your model.
By systematically checking your electrical connections and power supply, you can usually resolve the W407H warning and restore full functionality to your Truma combi boiler's electric heating mode.
