Truma Combi 4E & 6E:
The Definitive Guide
Heating and hot water in one compact unit. Why it remains the gold standard for UK professional builds.
What is the Truma Combi?
The Truma Combi is a dual-function appliance that provides both blown-air space heating and a 10-litre hot water reservoir. It is designed to be installed internally, usually under a bed or inside a bench seat, and uses a balanced flue system that vents through the side of the vehicle.
For UK van builders, the "E" variants (4E and 6E) are the most popular because they include integrated 230V electric heating elements. This allows you to heat your van and water using gas while off-grid, or using shore power when plugged in at a campsite — saving your LPG for when you really need it.
Gas, Electric & Mixed Modes
Gas Mode
Uses LPG (Propane/Butane). Fastest heating time and works anywhere.
Electric Mode
Uses 230V shore power. Silent operation and saves LPG fuel.
Mixed Mode
Combines both gas and electric for maximum heating boost in winter.
Combi 4E vs 6E
| Feature | Combi 4E | Combi 6E |
|---|---|---|
| Heat Output (Gas) | 2000W / 4000W | 2000W / 4000W / 6000W |
| Heat Output (Electric) | 900W / 1800W | 900W / 1800W |
| Gas Consumption | 160 - 320 g/h | 160 - 480 g/h |
| Water Capacity | 10 Litres | 10 Litres |
Amplios Verdict: For almost all MWB and LWB conversions (Sprinter, Crafter, Transit), the Combi 4E is perfectly adequate. The 6E is only necessary for extra-large expedition trucks or poorly insulated vehicles intended for deep winter use in Northern Scandinavia or the Alps.
Hot Water System
The integrated 10-litre water tank is made of high-quality stainless steel. It can heat water from 15°C to 60°C in approximately 20 minutes (using gas). One of the best features of the Combi is that it can heat the cabin without heating the water, or heat the water without heating the cabin — perfect for summer showers.
FrostControl Safety Valve
Every Truma Combi includes a FrostControl valve. This mechanical safety valve automatically opens and drains the water tank if the ambient temperature drops below 3°C, preventing ice from damaging the internal tank.
CP Plus vs iNet X
CP Plus (Standard)
The classic digital control panel with a rotary push-button. It allows for precise temperature setting, timer programming, and fan speed control. Reliable and intuitive.
iNet X (Modern)
A full colour touchscreen that acts as a central hub. It offers app connectivity, over-the-air updates, and much more detailed diagnostic information if the system encounters a fault.
Is it right for your van?
If you want a "one-stop" solution for both heating and hot water, and you have the budget for a premium installation, the Truma Combi is the winner. However, it does require a dedicated LPG installation (gas locker, copper pipework, Gas Safe sign-off).
If you are building a smaller "weekender" van or want to avoid gas entirely, you might consider the **Truma VarioHeat** (heating only) or a diesel-powered alternative like the **Webasto Air Top**.