Truma Combi 4E heater, gas and electric, for your motorhome, caravan or campervan: three modes, 4000 W on gas and 3800 W combined
The Truma Combi 4E heater adds 230 V electric heating rods to the Combi 4, so it can run on gas, on the campsite mains hook-up or on both sources at once. It also keeps the built-in 10-litre water heater, so you still get heating and hot water from a single appliance in your motorhome, caravan or campervan.
On a campsite you can heat with electricity alone, at 900 W or 1800 W depending on the fuse rating available. On the road, or far from any socket, you use gas instead, at 2000 W and 4000 W. And in very cold weather you can use combined mode (max. 3800 W), which according to Truma is intended for very low outside temperatures; on gas alone it reaches 4000 W.
It comes with the iNet X Panel 2 control panel, which has a capacitive touchscreen and which you can also operate over Bluetooth. Note, though, that the box does not include the exhaust or the water connection set, and fitting, including the electrical part, is a job for technicians.
Benefits of the Truma Combi 4E heater
- Three ways to heat: gas only, 230 V campsite electricity only, or both at once, with a maximum of 3800 W combined.
- In combined mode it gives priority to electricity, and the gas burner only comes on when more power is needed.
- In combined mode, if the 230 V supply is disconnected or fails, the heater switches to gas by itself.
- On the campsite hook-up you save gas and, according to Truma, electric mode is completely silent and produces no emissions.
- Electric power to suit you: 900 W (3.9 A) or 1800 W (7.8 A), depending on the fuse protection at the campsite.
- According to Truma, it heats the vehicle and the water particularly quickly and uses little energy.
- 10-litre stainless steel tank, with water heated by gas or by electricity and, in summer, without switching the heating on.
- Four warm-air outlets and, if the tank is empty, it keeps heating the living space.
- You control it from the panel or from the iNet X App over Bluetooth, with up to 6 timers.
- Weighs 15.5 kg without water, with the electric rods already built in.
Is it compatible with your motorhome, campervan or caravan?
Truma limits use of the Truma Combi 4E heater to motorhomes of vehicle class M1 and caravans of class O, and it also asks for a gas installation that complies with EN 1949. If your campervan is registered as a motorhome, it meets the first requirement; if it is a commercial vehicle (class N), you cannot fit it.
Size matters too, since the range is divided into small, medium and large vehicles. So the Combi 4E is for small and medium-sized ones and the Combi 6E for large ones. To use electric mode you also need a campsite hook-up with sufficient fuse protection.
Vehicle, space and electricity for the Truma Combi 4E heater
Start with the space and the hook-up, because both affect the installation. Truma also lists the vehicles in which you cannot install it.
| Requirement | What Truma says |
| Permitted vehicles | Motorhomes of vehicle class M1 and caravans of class O, with the gas installation carried out to standard EN 1949. |
| Vehicles not permitted | Coaches and buses (M2 and M3), commercial vehicles (class N), boats and other watercraft, hunting or forestry huts, weekend homes and canopies; nor is it allowed in trailers or vehicles that carry dangerous goods. |
| Vehicle size | Small and medium-sized. |
| Unit dimensions (L x W x H) | 510 x 450 x 300 mm |
| Minimum installation dimensions | 540 x 500 x 350 mm, with additional space for the gas connection, the water connections and the drain valve depending on the installation situation. |
| 12 V supply | The unit runs on 12 V; you will find the consumption in the technical specifications. |
| 230 V mains supply | For electric operation, check that the fuse protection of the campsite supply can handle the power you set: 900 W (3.9 A) or 1800 W (7.8 A). The cable reel must be fully unwound so that the cable does not overheat. |
| Controls and accessories | Only with the matching Truma control panels and accessories. The vehicle manufacturer decides where the room temperature sensor goes. |
So the type of vehicle, the space and the campsite hook-up are the three points to confirm first. If any of them is a problem, discuss it with your installer before you buy.
Gas, regulator and driving
Even if you have mains electricity, the gas side still has to be installed correctly. To heat while you drive you need a safety shut-off device, such as the MonoControl CS regulator, and with two cylinders Truma recommends the DuoControl CS vertical or the DuoControl CS horizontal.
| Topic | What Truma says |
| Gas and pressure | LPG (propane / butane) at 30 mbar. The service pressure of the supply and that of the unit (rating plate) must match. |
| Regulator | Regulating devices to DIN EN 16129 (in vehicles), with a fixed outlet pressure of 30 mbar and a flow rate that covers at least the maximum consumption of all appliances. Truma recommends the MonoControl CS and, with two cylinders, the DuoControl CS. |
| Cylinders | Upright, drawing gas in the vapour phase; you must not draw it in the liquid phase. |
| Cold | At temperatures around 0 °C or below, the regulator or the changeover valve must work with the EisEx regulator heater. |
| While driving | Safety shut-off device in accordance with UNECE Regulation 122, e.g. the MonoControl CS. Without it, you keep the cylinder closed and put up warning signs in the gas locker and near the control panel. |
| When not to use it | Never during refuelling, in car parks, garages or on ferries: switch it off at the control panel, and it must not be possible to switch it on remotely. |
So electric mode is for the campsite, and heating while driving always depends on gas and its regulator. Also, the conditions for the cowl, the water and the warm-air ducts are in the installation section.
Technical specifications of the Truma Combi 4E heater
Truma's documents call it the Combi 4 E; these are its official figures. Because the dimensions, the gas and the service pressure affect the installation, they already appear in the compatibility table.
| Specification | Value |
| Water capacity | 10 litres (stainless steel tank) |
| Water heating time from approx. 15 °C to approx. 60 °C | water heater only: approx. 23 min (EN 15033); heating + water heater: approx. 80 min |
| Pump pressure / system pressure | max. 2.8 bar / max. 4.5 bar |
| Air flow (free-blowing, without ducting) | max. 249 m³/h with 3 outlets; max. 287 m³/h with 4 outlets |
| Standby heat consumption | 8.6 g/h in gas operation (EN 15033) |
| Quiescent current at 12 V | approx. 0.001 A |
| Heating the water only, at 12 V | max. 0.5 A |
| FrostControl heating element (optional) at 12 V | max. 0.4 A |
| Protection type | IPX1 |
| 12 V fuse | 10 A fast-acting, 5 x 20 mm |
| Rated heat output on gas (automatic stages) | 2000 W / 4000 W |
| Gas consumption | 160 – 335 g/h |
| Data according to EN 624 | Qn = 4.8 kW (Hs), 345 g/h, C13, I3 B/P(30) |
| Consumption at 12 V, heating + water heater | 1.2 – 6.5 A |
Electrical, combined and weight data for the Truma Combi 4E heater
Because the 230 V rods add these figures, we have put them in a separate table. That way you can compare the electric and combined output with the output on gas.
| Specification | Value |
| Output in electric operation (230 V) | 900 W / 1800 W |
| Output in combined operation (gas + electric) | max. 3800 W |
| Consumption at 230 V | 3.9 A (900 W) or 7.8 A (1800 W) |
| 230 V fuse | 10 A fast-acting, tripping delay “H” |
| Weight without water | 15.5 kg (with peripherals: 16.0 kg) |
It weighs 15.5 kg without water, which is more than the Combi 4, at 14.4 kg. According to Truma, the figure with peripherals includes the control panel, the bracket, the cables, the flexible hoses, the fixing material and the FrostControl, although not everything comes in the box.
How the Truma Combi 4E heater works
It is a blown air heater with a built-in water heater and, in addition, 230 V electric heating rods. The Truma Combi 4E heater therefore lets you choose between three energy sources:
- Gas only (propane or butane), for stand-alone use: the unit chooses the output stage it needs by itself.
- 230 V electricity only, for stationary use on the campsite: you preselect 900 W (3.9 A) or 1800 W (7.8 A) depending on the fuse rating available.
- Gas and electricity at once, the combined mode, which is only possible in heating operation.
In combined mode, when the power demand is low, for example to hold the temperature steady, electricity from the 230 V supply has priority. The gas burner only switches on when the power demand rises.
When the demand is higher, for example when heating the vehicle from cold or in low outside temperatures, Truma advises choosing gas or combined mode so that there is always enough power.
On the other hand, the unit heats the water with gas or with electricity, not with both at once: if you have selected combined mode, it uses electricity for the water and, if the 230 V supply is cut, it switches to gas by itself.
Sensors, heating without water and driving
While a room temperature sensor measures the air in the vehicle, internal sensors monitor the water. The unit reduces its output before it reaches the set temperature. With an empty tank you can heat the living space alone, on gas, on electricity or in combined mode.
When you drive, the fan-assisted burner keeps running on gas, but it requires the safety shut-off device from the table above. Electric mode, on the other hand, is intended for stationary use on the campsite.
iNet X Panel 2 control panel for the Truma Combi 4E heater
This version comes with the iNet X Panel 2, which controls the heating, the air-conditioning system and the Truma LevelControl. You operate it with the 4.3-inch capacitive touchscreen or with the free iNet X App. According to Truma, the automatic climate control and the timer also take care of the day-to-day regulation for you.
| Specification | Value |
| Display | TFT-LCD 4.3" touchscreen (capacitive) |
| Power supply | 12 V DC (8 V DC – 16 V DC) |
| Consumption | 1.5 W |
| Interfaces | TIN bus, CI bus, CAN bus and Bluetooth Low Energy (BLE) |
| Operating and storage temperature | -30 °C to 60 °C |
| Battery | CR 2032, service life of around 8 years; the app warns you when it needs replacing |
| Weight | approx. 190 g |
| Dimensions (L x W x H) | 89 x 118 x 31 mm |
| Protection | class III; front IP20, rear IP00 |
| Physical buttons | Home and Back |
| Phones connected at once (iNet X App over Bluetooth) | up to 3 |
| Timers | up to 6 |
| Appliances it controls | heating, air-conditioning system and Truma LevelControl |
| Remote control | with the iNet X Connect module (optional, not included) |
| Manufacturer's warranty | 24 months |
As you can see, it is a connected unit: it supports up to 3 phones at once and up to 6 timers. The app also warns you when the battery, which according to Truma lasts around 8 years, needs changing.
What it shows and how it is updated
The panel shows the indoor climate, the outdoor and indoor temperatures and error messages with suggested solutions; if you install the Truma LevelControl, it adds the gas level. You update it from the app when you have internet and Bluetooth, and an update can take up to 15 minutes.
If you leave the panel unused, after 60 seconds it goes to the lock menu and after another 60 to standby mode; phones can still control the appliances. Clean the screen with a non-abrasive cloth and water, or with mild soap. To control the heater remotely you also need the optional iNet X Connect module.
Installation and fitting of the Truma Combi 4E heater
Only qualified and authorised personnel (technicians), with the installation and operating instructions to hand, may fit, repair and inspect the Truma Combi 4E heater. Because there is also a 230 V mains connection, Truma warns of danger to life from electric shock when changing the fuse or the mains cables.
| Item | What the installer must allow for |
| Cowl | Do not block it, and Truma prohibits fitting covers over the cowl. When cleaning the vehicle, do not spray water directly at it. The unit needs an exhaust system, which is not in the box. |
| Opening window | If the cowl is near or below a window that opens, you need an automatic cut-off device; under EN 1949, a window switch if it is less than 30 cm away. |
| Warm-air ducts | Truma does not allow the unit to run without them. |
| Mains water | If you connect the vehicle to a mains water supply (external pressure), a pressure-reducing valve so that the water heater does not have to withstand more than 2.8 bar. |
| Solar installation | Under EN 1648, always a battery with a charge controller or a voltage regulator (11 V – 15 V; AC voltage ripple < 1.2 Vpp) between the panels and the heater. |
| Yellow label | The installer or the owner must stick the enclosed warning label in a place clearly visible to all users, e.g. the wardrobe door. |
| Mains cable | If the mains connection cable is damaged, the manufacturer, its customer service or a similarly qualified person must replace it, to avoid hazards. |
In short, before finishing, the installer must check the exhaust, water, window, electrics and label.
Frost and FrostControl
If the water freezes, the unit can suffer serious damage, because the Combi has no built-in frost protection. Truma's solution is the FrostControl valve, which is part of the FC TB (36100-01) or FC JG (36100-02) water connection set; that set is not in the box.
The valve works without electricity and drains the water heater when there is a risk of frost. It opens by itself below about 3 °C and you can only close it by hand when it is about 7 °C or more. When the vehicle is parked in frosty weather, always drain the water heater, because Truma's warranty does not cover frost damage.
230 V fuse and overheating protection
Before you open the electronics cover, you must disconnect the unit from the power supply at all poles. The 230 V fuse is inside, and you may replace it only with an equivalent one: 10 A, fast-acting with tripping delay “H”, as Truma specifies.
For 230 V operation, the heater also has a mechanical overheating switch. If the 12 V supply is interrupted during operation or run-on, it can trip. To reset it, let the heater cool down, remove the connection cover and press the reset button; then put the cover back.
What the box contains and the accessories you need
The version with the iNet X Panel 2 (Truma 33715-20) includes:
- Combi 4E heater with water heater.
- iNet X Panel 2 control panel.
- 6 m control panel cable.
You should also know what is not in the box: the following items, which you need to allow for before you arrange the installation. The contents do not list the warm-air ducts, although the unit cannot run without them.
- ZR 80 wall cowl or roof cowl, with its exhaust and combustion air pipes.
- FC TB (36100-01) or FC JG (36100-02) water connection set, the one that includes the FrostControl valve and the elbows.
- FrostControl and optional heating element (70070-01).
- iNet X Connect, the optional remote module.
- Warm-air ducts with their outlets.
- MonoControl CS or DuoControl CS gas regulator.
Official Truma part numbers for the exhaust
These are Truma's part numbers for the exhaust system. Use them as a guide with your installer, because none of them comes in the box.
| Part number | What it is | What it is for |
| 36240-01 | Complete ZR 80 wall cowl kit: inner cowl part, 1.1 m exhaust pipe, 1 m combustion air pipe and clamps (without the outer cowl part) | Routing the exhaust gases out through the vehicle wall |
| 34122-01 | Complete CD roof cowl kit: 3 m AA 3 exhaust pipe, 3 m ZR 80 combustion air pipe and clamps | Routing the exhaust gases out through the roof |
| 36140-01, 36151-01 / -05 / -08 / -09 / -10, 34051-01, 39320-00, 39580-00, 39590-00, 34070-01, 34080-01 | Loose parts: ZR 80 inner part, outer parts in cream, bianco, light grey, black and anthracite, DKC 2 roof cowl, pipes by the metre, clamp, 30 cm extension and SDDF wall bushing | Completing or extending the wall or roof cowl |
Official Truma part numbers for water, air and other accessories
Water, warm air and the window each have their own official part numbers, which Truma groups as follows.
| Part number | What it is | What it is for |
| 36100-01 | FC TB water connection set: FrostControl TB power-free drain valve, TB elbows for Ø 10 mm flexible water hoses and black PVC flexible hose (TB = barbed connection) | Connecting the water and draining the water heater if there is a risk of frost |
| 36100-02 | FC JG water connection set: FrostControl JG power-free drain valve, JG elbows for Ø 12 mm rigid pipe and transparent PVC flexible hose (JG = John Guest system) | The same as the one above, with rigid pipe |
| 70070-01 | FrostControl heating element with 1.5 m cable | Filling the water tank sooner, regardless of the ambient temperature |
| 34092-01 / 34310-01 | Black BGC elbow for connecting warm-air ducts (Ø 65 mm or Ø 72 mm) directly and black CB blanking cap | Connecting or closing off a warm-air outlet |
| 34030-34700 / 34020-01581 | Window switch for standard caravan opening windows, and narrow window switch | Switching the heater off when you open the window |
| 47000-00140 | Alternative iNet X room temperature sensor (e.g. FFC2); Truma cites it for the iNet X Panel control panel | Alternative sensor that connects directly to the control panel |
Truma also offers control panel cables in various lengths (maximum 10 m), and requires the window switch if the cowl is below an opening window or less than 30 cm from it.
Who is the Truma Combi 4E heater for?
The Truma Combi 4E heater suits you if you move between the road and the campsite and want to choose your energy source. For example, if any of these situations sounds familiar:
- You spend long periods on campsites with electric hook-up and prefer to save gas.
- You travel in winter and want to combine gas and electricity when the cold bites.
- Your motorhome or caravan is small or medium-sized.
- Noise bothers you and you value the fact that, according to Truma, electric mode is quiet.
- You want to control the heating from your phone, with up to 6 timers.
- Your campervan is registered as a motorhome (class M1); the heater cannot be fitted in a commercial vehicle (class N).
Maintenance, cleaning and warranty for the Truma Combi 4E heater
To keep the Truma Combi 4E heater working well, clean the installation space at least once a year and have specialist technicians check the unit's cleanliness. Also use the safety and drain valve, at least twice a year, to remove limescale. For safety, children must not carry out maintenance or cleaning.
Sterilise and descale the tank regularly. Products sold in camping shops are suitable and, against limescale, so are commercial descalers, vinegar essence or citric acid: pour them in through the water inlet, leave them to work and rinse thoroughly with clean water.
To combat micro-organisms, Truma adds a complementary thermal method, in gas operation: with the water at 60 °C the burner switches off, and if you leave the unit switched on for at least another 30 minutes without drawing hot water, the residual heat takes it to 70 °C.
Solar panels and smell of gas
With solar panels, Truma requires a battery with a charge controller or a voltage regulator between them and the heater. When disconnecting the battery, disconnect the charge controller first. If you smell gas, put out all flames, do not use electrical switches or phones, ventilate, get everyone out, close the cylinders and do not use the installation again until technicians have checked it.
Manufacturer's warranty
The manufacturer covers material or manufacturing defects for 24 months with a voluntary warranty. It is valid in the European Union, Iceland, Norway, Switzerland and Turkey, and Truma or an authorised Service Partner handles it and decides whether to repair or replace. It is a manufacturer's warranty, so it does not replace the statutory one, and frost damage is excluded.
Frequently asked questions
What is the difference between gas, electric and combined mode on the Truma Combi 4E heater?
On gas, the heater runs independently of the mains, at 2000 W or 4000 W. On electricity, however, it uses the campsite's 230 V at 900 W or 1800 W. Finally, in combined mode it uses both sources (max. 3800 W), gives priority to electricity and lights the burner only when more power is needed.
Can I use the Truma Combi 4E heater while driving?
Yes, on gas, provided the installation has a safety shut-off device, such as the MonoControl CS regulator. If it does not, you must keep the cylinder closed while driving, with warning signs. Electric mode, on the other hand, is intended for stationary use on the campsite.
What happens if the campsite power is cut?
With combined mode selected, if the 230 V supply is disconnected or fails, the heater automatically switches to gas operation.
Combi 4E or Combi 6E: which one do I need?
It depends on the size of the vehicle: the Combi 4E is for small and medium-sized vehicles and reaches 3800 W combined, while the Combi 6E is for large vehicles and reaches 6900 W. Both also weigh 15.5 kg without water and share the same dimensions.
What else do I need to buy to install it?
The box does not include the exhaust system or the water connection set with the FrostControl, nor the warm-air ducts. You also need a gas regulator such as the MonoControl CS, and a qualified installer, because Truma only allows fitting by technicians.
