How to Use the Truma Aventa Air Conditioner in Your Mars Caravan

How to Use the Truma Aventa Air Conditioner in Your Mars Caravan

If your Mars caravan is fitted with a Truma Aventa roof air conditioner, this guide covers everything you'll actually use day-to-day — cooling, fan-only, reverse-cycle heating (on heat-pump models), and how to run it safely off the inverter when you're off-grid.

Controls vary slightly across the Aventa range (Compact, Compact Plus, Comfort). Some Mars vans use the handheld remote; others use the Truma CP plus control panel. The principles below apply to both.

Quick Highlights

  • Modes: Cooling, Automatic, Air Circulation (fan-only). Some models also include Heating (reverse cycle).
  • Temperature: Adjustable in 1°C steps, typically 16–31°C (model dependent).
  • Fan speeds: Low / Medium / High (Auto adjusts for you).
  • Comfort features: Sleep/Night mode, timer, ambient lighting (if fitted).
  • Power supply: 230–240V AC — mains, generator, or inverter (lithium-equipped vans).

What It Is & How It's Controlled

The Aventa is a 240V roof-mounted unit with an internal air distribution box (the ceiling vent you see), and either a handheld remote or a CP plus control panel as the user interface.

Handheld Remote (Most Mars Installs)

  • Point the remote at the IR receiver in or near the ceiling air distributor.
  • Press On/Off to start, then choose Mode → Temperature → Fan speed.

Truma CP Plus Control Panel (Some Installs)

Where fitted, the CP plus is the primary controller — follow the prompts on the panel for mode, temperature and fan instead of using the handheld remote.

Power Sources — Mains, Generator, Inverter

Mains Power

The preferred option for longer runs. Connects via the 240V inlet. No drain on the battery system.

Generator

Make sure the generator is correctly rated for the aircon's starting and running load, connected via a compliant 240V lead, and warmed up per the manufacturer's instructions before you switch the aircon on.

Inverter (Lithium-Equipped Mars Vans)

Many Mars caravans with large lithium banks and a 2000–3000W pure sine wave inverter are set up so the aircon circuit can run from the batteries via the inverter. Important guidelines:

  • Running the aircon from the inverter pulls a lot of current — use it for short bursts, not all-day continuous running.
  • Monitor battery state-of-charge on your Redarc/Projecta display while running off-grid.
  • Confirm your inverter is switched on and configured to supply the aircon circuit — per your Mars handover instructions.
  • Switch off other heavy 240V loads (microwave, kettle) when running the aircon on inverter.
  • If you're unsure whether your van supports aircon-on-inverter, check your model documentation or contact Mars support before trying.

Before You Run It

  • Ventilate first: open up briefly to dump hot air, then close everything for cooling.
  • Park smart: shade and blinds make a massive difference.
  • Power check: confirm 240V is live (mains, generator running, or inverter on and configured).
  • RCD and breakers: main 240V RCD and aircon breaker both ON.
  • Airflow: ceiling outlets and roof intake unobstructed.
  • Filters: reasonably clean (see Cleaning section).
  • If running on inverter: battery healthy — well above 50% on most setups.

How to Cool the Van

  1. Press On/Off.
  2. Select COOL mode.
  3. Set the temperature — start around 22–24°C for comfort.
  4. Pick a fan speed — High for fast pull-down on a hot day.
  5. Adjust the air distributor vents to spread cool air evenly.

Humid days tip: keep doors and windows closed and run a higher fan speed — that reduces condensation forming on the distributor.

How to Heat — Heat-Pump Models Only

Some Aventa models (commonly the Aventa Comfort) include reverse-cycle heating. If your controller shows a HEAT option, you can run it like home reverse-cycle aircon.

  1. Power on.
  2. Select HEAT mode.
  3. Set a modest target temperature (19–21°C).
  4. Choose a fan speed or use Auto.

Our Recommendation for Heating

Mars caravans fitted with a diesel heater should use the diesel heater as the primary heat source — especially off-grid. Reverse-cycle through the aircon draws a lot of power (a problem on inverter) and is less efficient at very cold ambient temperatures. The diesel heater uses diesel for heat and only a small 12V load for fans, which is far more efficient off-grid.

Use the Aventa's Heat mode as a backup, or when you're on mains and conditions are mild. If your unit shows no HEAT option, it's a cooling-only model — use the diesel heater.

Fan-Only / Air Circulation

Moves and filters cabin air without active cooling or heating. Useful for:

  • Ventilation at night
  • Reducing stuffiness
  • Spreading warm air from the diesel heater front-to-back when running together
  1. Select AIR CIRCULATION (or Fan).
  2. Choose your fan speed.

Sleep / Night Mode

Reduces fan and compressor speed for quieter overnight operation. Look for the Sleep or Night function on your remote.

Timer

Most Aventa remotes let you schedule Timer ON and Timer OFF (commonly up to 24 hours ahead). Handy for pre-cooling the van before bed or auto-shutoff overnight.

Turning the Aircon Off

  1. Press the Power button.
  2. The compressor stops; the fan may run briefly to cool internal components.
  3. Once stopped, switch off mains, generator or inverter as part of your normal pack-up.

Don't rapidly cycle the aircon — allow a few minutes between restarts to protect the compressor.

Cleaning & Maintenance

  • Filters and panels: clean or replace at least every 12 months — more often in dusty conditions.
  • Washable panels: remove, rinse under clean/lukewarm water, dry fully, refit.
  • Never run without filters — reduces performance and risks internal damage.
  • Roof inlets/outlets and condensation drains: keep clear of leaves and debris.
  • Wipe only: soft, damp cloth. No harsh cleaners. Never pressure-wash into the aircon openings or steam-clean.
  • Off-season: short runs in both cooling and (if fitted) heating modes keep the components in good shape.

Quick Troubleshooting

  • Not cooling enough: doors/windows closed? Filters clean? Roof airflow clear? Try a higher fan speed.
  • Moisture on the ceiling distributor: close everything up and run a higher fan speed.
  • Water dripping from the distributor: check for blocked condensation drains or debris around the roof outlets.
  • Remote not responding: replace batteries, confirm line-of-sight to the IR receiver.
  • Fault light or error: power cycle. If the fault persists, contact Mars support or Truma.
  • RCD trips when aircon starts: usually undersized generator or an issue with the aircon circuit — book service.

When to Contact Support

Stop using the unit and contact Mars or an authorised Truma service agent if you see:

  • Breakers or RCDs repeatedly tripping when the aircon starts
  • No cooling or heating even though the unit appears to be running
  • Burning smells, smoke, or visible damage
  • Unusual loud or grinding noises
  • Water leaking inside the van from around the air distributor

Include in your ticket: Mars model and VIN, power source in use (mains/generator/inverter), the mode, set temperature and fan speed at the time, and any error codes or lights shown on the unit or remote.

Safety Notes

  • Use suitable power sources — stable shore power is best.
  • No DIY repairs — covers, internal electrical, and refrigerant work are all licensed-tech jobs.
  • Don't pressure-wash or steam-clean any part of the aircon system.