AUTOTERM AIR 4D diesel air heater for marine use is an autonomous 12 V heating system with a Marine Small Set for heating and dehumidifying cabins in boats, yachts, and vehicles. The heater delivers 1.0–4.0 kW of heating power and a heated air volume of 70–168 m³/h.
The heater uses diesel according to EN 590 or HVO100 according to EN 15940. Fuel consumption is between 0.12 and 0.514 l/h, while the electrical power consumption for this 12 V variant is 10–57 W. Integrated sensors and safety systems monitor, among other things, the flame and overheating, and automatically stop the heater if a fault is detected. The control unit also features an altitude sensor for operation at altitudes up to 4,200 m above sea level, and the model is designed for operation at temperatures down to −45 °C.
The heater itself measures 402 × 157 × 188 mm and weighs 5.5 kg. The intake for the air to be heated is Ø83 mm, and the hot air outlet is Ø100 mm. The air duct system must start with at least Ø90 mm, which requires a suitable adapter at the Ø100 mm outlet. The first meter after the hot air outlet must be routed as straight as possible without sharp or 90° bends. For installations with multiple outlets, at least one outlet must remain permanently open.
The heater is mounted horizontally on a flat surface with the mounting flange as the contact point. There must be at least 50 mm of free space at the air intake, 150 mm at the hot air outlet, and 60 mm above the unit. The combustion air connection is Ø26 mm, and the exhaust connection is Ø24 mm. Exhaust gases must be routed completely outside the vessel or vehicle, and the outlet must be positioned so that water can drain freely. For marine installation, the heater must be protected against seawater, rainwater, condensate, dirt, heavy vibrations, and contamination from oil, fuel, or engine exhaust.
The power supply should be connected directly to the vessel's battery or auxiliary battery and must remain connected until the heater's cooldown cycle is complete. The supply system uses 25 A fuses. The heater can be operated with compatible panels such as Simple Control, OLED Control Panel, Comfort Control, Push Control, and Touch Control. An analog panel with item no. 50.251.11, a digital panel with item no. 50.251.01, and a 5 m extension cable with item no. 50.251.12 can be used as supplementary control equipment.
The Marine Small Set includes a cable for the fuel pump with connector, fuel dosing pump, air intake pipe with silencer, 1.8 m cable for the control panel, Ø24 mm thermal insulation, exhaust silencer with mounting kit, 1 m exhaust pipe, 1.5 m nylon fuel hose, and mounting brackets. An air distribution kit with three outlets is available as item no. 50.254.63, while the kit with four outlets has item no. 50.254.64. Exhaust adapters 50.255.01, 50.255.02, and 50.255.03 can be used for the Ø24 mm exhaust system.
The recommended boat length is 10–12 m in Mediterranean climates and 8–10 m in Nordic climates. The AIR 4D is certified according to UNECE R10 and R122.
Key featuresAutonomous diesel-powered air heater with marine mounting kit
12 V DC and 1.0–4.0 kW heating power
Heated air volume of 70–168 m³/h
Fuel consumption of 0.12–0.514 l/h
Electrical power consumption of 10–57 W
Integrated fault, flame, and overheating sensors
Product dimensions of the heater: 402 × 157 × 188 mm
Recommended for boats of 8–10 m in Nordic climates and 10–12 m in Mediterranean climates
Certified according to UNECE R10 and R122
