Truma CombiNeo 4
(E) / CombiNeo 6 (E)
The Truma CombiNeo is a combined warm air heater with an integrated water container (5.6 litre capacity) designed for installation in motorhomes and caravans. It supports gas, electrical, and mixed operational modes to provide efficient room heating and rapid hot water generation, even during vehicle transit.
View official manual on manufacturer's site ↗Technical Specifications
Master Troubleshooting & Diagnostics Matrix
| Error Code / Indicator | Symptom / Meaning | Possible Cause | Step-by-Step DIY Fix | Suggested Actions |
|---|---|---|---|---|
Appliance will not start | Gas supply disrupted or air in the gas line. | — | Confirm the gas cylinder and shut-off valves are open. It may take several attempts to draw gas fully through to the appliance. | DIY Safe |
W434H | Air bubbles have stopped appearing in the water container. | — | Switch off pressure pump, open FrostControl manually for about 15 seconds to drain approx. 2 litres of water, close FrostControl, switch pump back on, open hot water tap to bleed air, and wait briefly for the air bubble to rebuild. | DIY Safe |
Water's running straight back out - the water container won't fill | FrostControl is open. | — | Close FrostControl. | DIY Safe |
The water container won't drain even with FrostControl open | Bottom outlet of FrostControl or L-piece blocked, water pipe frozen, or aeration system blocked. | — | Check openings for dirt, slush, ice, or leaves and remove; thaw frozen water pipes; check venting hose for kinks or blockages. | DIY Safe |
Water drips/flows from elbow connection valve into venting hose | The elbow connection valve is scaled up or dirty. | — | Descale, clean, or replace the elbow connection valve. | DIY Safe |
Water is dripping/flowing from FrostControl floor outlet | Water pressure too high. | — | Check the pump pressure doesn't exceed 2.8 bar / 280 kPa, fitting a pressure reducer if it's on mains water. | DIY Safe |
Frequently Asked Questions
Q: Can the CombiNeo be operated while driving?
Yes, operation while driving is permitted provided that national regulations and rules are followed, and an appropriate safety shut-off device (such as Truma MonoControl CS or DuoControl CS) is installed.
Q: Why does FrostControl open automatically?
FrostControl opens automatically at temperatures below approximately 3 °C to protect the water system from frost damage, or in the event of overpressure in the system.
Q: How do I deal with winter operation using gas?
For operation at temperatures below 10 °C, propane must be used because butane stops vaporizing at around 0 °C.
Q: How often must the water container be descaled?
Descale the water container once a year, or whenever the control panel prompts you to.