Truma UltraRapid Hot Water System – Basic Operation

Truma UltraRapid Hot Water System – Basic Operation

The Truma 14L hot water system gives you stored hot water for washing, showering and general use around the van. Depending on your setup, it may run on gas, 240V power, or both together.

Before You Turn It On

  • Make sure the hot water system is filled with water before operating it.
  • Check that the drain valve is closed.
  • Turn on your water pump or connect to mains water and open a hot tap until water flows steadily. This confirms the tank is full.
  • Remove the external cowl cover before operating the unit.

Important: Never operate the Truma hot water system without water in the tank.

Gas Operation

  1. Remove the external cowl cover.
  2. Open the gas bottle and make sure the gas isolation valve is on.
  3. Turn the Truma unit on at the control switch.
  4. Select the temperature setting if your controller allows it.

If there is air in the gas line, the unit may not ignite straight away on first use. If that happens, switch it off, wait a few minutes, then try again.

Heating Time

As a guide, the 14L system generally takes around 20 to 25 minutes to heat the water.

Using Hot Water

Once the water is up to temperature, you can use the hot taps and shower as normal. As hot water is used, cold water enters the tank, so water temperature will gradually reduce over time.

Turning the Unit Off

  • Turn the unit off at the internal control switch.
  • If you have been using gas, you can then turn off the gas supply if required.
  • Once the unit is no longer in use, refit the external cowl cover.

Important Notes

  • Always remove the cowl cover before use.
  • Always refit the cowl cover before travelling.
  • Never run the system without water in it.
  • If frost is expected, drain the system to help prevent damage.
  • If connected to high-pressure mains water, a pressure reducer may be required depending on the setup.

If the Unit Does Not Heat

  • Check that the tank is full of water.
  • Check that the cowl cover has been removed.
  • Check the gas bottle is on and has gas.
  • Check 12V power is available for ignition and controls.
  • If using 240V mode, make sure the van is connected to mains power and the electric switch is on.

If the unit still does not operate correctly, refer to the Truma manual or contact Mars Campers for support.


    • Related Articles

    • Mains Water Connection and Filling Fresh Water Tanks – Basic Operation

      Your Mars van can generally be used in two ways for water: Mains water – when connected directly to a park or site tap. Tank water – when using the van’s onboard fresh water tanks and pump. Connecting to Mains Water Locate the mains water inlet on ...
    • Dometic Cassette Toilet – Basic Operation

      The Dometic cassette toilet is simple to use and designed for everyday convenience while travelling. This guide covers the basic operation of the toilet from inside the van. Before You Use the Toilet Make sure the cassette is correctly installed. ...
    • Jockey Wheel, Safety Chains and Breakaway System – Basic Operation

      Before towing, make sure the van is correctly connected to the vehicle and that the jockey wheel, safety chains and breakaway system are all secured properly. Jockey Wheel The jockey wheel is used to raise and lower the drawbar when connecting or ...
    • Electric Awning – Basic Operation

      Your Mars van may be fitted with an electric awning to give you quick and easy shade at the push of a button. Before You Extend the Awning Make sure the area beside the van is clear. Check there are no trees, poles or other obstacles in the way. Make ...
    • AU Focus Diesel Heater – Basic Operation

      The AU Focus diesel heater is designed to keep your van warm and comfortable in colder conditions. It uses diesel as the fuel source and 12V power to run the electronics, fan and start-up process. Before You Start Make sure there is enough diesel in ...