• Is it permissible to run one 75 mm return air pipe and two outlet pipes on the Viking Air?

    Viking Air needs two 75 mm pipes in both ends. Using a single pipe would overheat the unit.

  • Before contacting a Wallas professional, please check the following items:

    Fuel, fuel filter, and fuel pump

    Are you using the correct fuel type?

    Is the freezing point of the fuel type high enough for the current weather condition? 

    Has water entered the fuel tank? 

    Is the fuel moving in the fuel line, is the pump pumping fuel, are the connections tight?

    Is the fuel filter blocked? 


    Operating voltage, overheat protection, fuses

    Is the battery fully charged? Operating voltage must be above 12 V in GB heaters and 10 V in Viking/Spartan/40 EA during the start-up phase, measured from the unit’s adapter.

    Are the main power cables and joints securely connected? 

    Are joints, fuses, or fuse holders oxidized?


    Exhaust pipe

    Does combustion air have access to the unit?

    Is there a blockage in the exhaust pipe?


    Warm air ducting

    Are the warm air hoses flattened and restricting the air flow?

    Are the warm air vents open?


    If above mentioned items are all working, but the unit doesn’t start or operate, please contact the nearest authorized Wallas-Marin distributor or Service Center. Have your product name and serial number ready.

  • If water has entered the fuel tank, what do I need to do?

    – Diesel stored in tanks can become contaminated by water (usually condensate). If this happens, 3% to 5% isopropyl alcohol can be added to the fuel, but ONLY in the case of this being fuel that will be used solely in the heating system.

    If your Wallas product’s diesel supply is the same as the main engine, DO NOT add isopropyl alcohol to the fuel. Adding alcohol to fuel can eliminate natural lubricity from the fuel. While fuel lubricity is not important to Wallas products, it is critical to diesel engine fuel injection systems. Wallas diesel products will tolerate most diesel fuel additives used by diesel engines. 

  • The heater makes unusual noise? What do I need to do?

    – Check the battery voltage, tighten all joints in the fuel line, make sure that fuel is not contaminated (dieselbug) and the fuel filter is not blocked.

  • My heater is locked and won’t operate. What do I need to do?

    – Heater lock is a safety feature that alarms you if something is not operating properly. Heater will also lock after 2-3 unsuccessful starts.

    GB heaters and stoves with PI Control panel: All three lights on the top of the panel flash and the heater cannot be operated. Inspect the heater for any issues to make sure it is safe to continue using it. If you need help, please reach out to your distributor. Once the issue has been resolved, follow the steps in the product manual for unlocking.

    Spartan Series, Viking Series, 40 EA heaters: A lock icon is displayed on the screen and the heater cannot be operated. Inspect the heater for any issues to make sure it is safe to continue using it. If you need help, please reach out to your distributor. Once the issue has been resolved, follow the steps in the product manual for unlocking.


  • What is the best way to clean the blower lid on my Wallas stove?

    – Wipe the blower lid with a damp cloth or a soft sponge. Use regular hand wash dish detergent if needed. Wipe with a damp cloth and dry with a microfiber cloth. If there is grime, a stainless steel detergent can be used. Always brush along the metal grain to avoid leaving any marks. Don’t use harsh brushes or detergents. 

  • How can I keep my Wallas stove looking like new?

    – Wipe it down after each use. Pour a few drops of ceramic cleaning detergent on a cold surface and wipe with paper towels. Wipe with a damp cloth and dry with a clean dry cloth. If you need to scrape off spills from the ceramic surface, use ceramic cleaning detergent and a cleaning spatula – never an abrasive sponge or chemically harsh detergents such as an oven cleaner or stain removers.

  • What should I do with my Wallas unit when I store my boat for winter?

    – We recommend the following if the unit has a separate fuel tank than the main fuel tank

    Empty the fuel tank

    Clean the fuel tank and change the fuel filter

    Re-fill the tank with clean new fuel when you start using your boat again


    – We recommend the following if the unit extracts fuel from the main fuel tank

    Change the fuel line filter

    Carry out the winter storage instructions recommended by the boat/engine manufacturer

  • I don’t need the heater during the hot summer months. Do I need to do something?

    – If possible, occasional use of the unit will keep it functional.

  • Do I need to take my Wallas unit to be serviced annually?

    – We recommend that Wallas units are serviced by an authorized Wallas distributor or service center after the first 500 hours of use, and then every 2000 hours/3 years, whichever comes first. We also recommend that you check the exhaust pipes for blockages/leaks annually.

  • How can I turn the heater on remotely?

    – Wallas GB heaters can be turned on remotely with a remote control (additional accessory), which is an online based tool. Wallas products that have the Advanced Control Panel (Viking Series, Spartan Series, 40 EA) can be paired with a Wallas mobile app and be controlled remotely. While you are near the boat, the connection works through a short-distance wireless connection without any additional equipment needed. If you would like to access the heater for instance from home, you can do it with the mobile app through a WiFi connection, if your boat has a router. 

  • Is there any exposed flame in Wallas diesel heaters?

    – No, the air-diesel mixture creates combustion, which takes place in a closed chamber with no exposed flame. The combustion system is fully closed. 

  • Can exhaust fumes leak into the indoor space and do I need to have a CO detector?

    – The coaxial exhaust system in the Wallas heaters is very safe because of the duplex pipes. The inner pipe blows the exhaust gases outside and the combustion air is taken from outside through the outer layer. This solution also cools the exhaust system, and usually, no additional insulation is needed. The exhaust system is fully closed. We always recommend a CO detector in the boat/vehicle. It is a standard and required equipment in new boats as well. 

  • Since the fuel is extracted from the main fuel tank, can the heater drain the whole tank?

    – It is stated in the installation manuals, that fuel pickup should be shorter than the total height of the fuel tank to allow some fuel reserve on the bottom of the tank. If this is done correctly, the heater will never drain the tank. Also, the fuel consumption in Wallas heaters is very low 0,1-0,5l/h (0.02-0.13 gal./h).

  • Can Wallas heaters be used for floor heating?

    – Yes, when it is installed in cottages, tiny houses, and liveaboards. Wallas 40 EA is a perfect solution for floor heating and for producing domestic hot water.

  • Could more than one heater be installed for a large space?

    – Absolutely. Since there are many options, we always recommend discussing installation with a professional Wallas distributor to determine the most optimal solution.

  • Do Wallas products need a power supply?

    – Wallas products need a 12 V battery to operate, but they use a very low amount of power. They need a 12 V minimum to start. Starting current will typically surge to 7-9 amps and then settle to 8-10 amps, which can drop the available voltage momentarily. If available power drops below 11.6 V, the unit may go into the shut down cycle (Viking and Spartan heaters 10 V). Some users may need to start their main engine to ensure the available voltage is sufficient to start the device. In this case, usually power wires are too thin or the connection to the battery is oxidized. Once the device is running, it will continue to run on a battery but with a voltage well below 12 V, amps typically ranging between 0.5-4.5.

  • Are all Wallas heaters type approved for recreational vehicles?

    – Wallas XC Duo is a type-approved stove-heater for camper vans. Other Wallas heaters are primarily marine heaters, but they are also suitable for camper vans if they are installed retrofitted. 

  • Can I Install a Wallas product myself?

    – We always recommend having a Wallas professional install our products to avoid improper installation that can cause injury or property damage, but it is possible to install them yourself if you are technically oriented and able to follow the installation instructions in the Wallas-Marin product manual in detail. Wallas-Marin warranty is not valid if the installation instructions in the product manual and country-specific regulations have not been followed. It is the responsibility of the owner and the installer to determine which requirements and standards apply to specific installations. 

  • How long does a typical boat heater installation take?

    – Typically, a Wallas heater can be installed within 1 day. Careful planning saves on installation time.