AU Focus 2kW MZ Diesel Heater — How to Use, Prime, Maintain & Troubleshoot

AU Focus 2kW MZ Diesel Heater — How to Use, Prime, Maintain & Troubleshoot

AU Focus 2kW MZ Diesel Heater — How to Use, Prime, Maintain & Troubleshoot

The AU Focus 2kW MZ diesel heater is a 12V, ducted warm-air heater commonly fitted to caravans and campers. This guide covers everyday operation (MZ Bluetooth controller), first-start priming, shutdown, maintenance, and the most common fault codes.

Quick Highlights

  • Heat output: 2kW
  • Typical power draw: ~36W running (higher during ignition)
  • Average diesel use: ~0.36 L/h
  • Operating range: -41°C to +50°C (altitude: < 4,000m)
  • Startup & shutdown cycles: allow the full cycle to reduce smoke/carbon build-up

Safety Notes (Read First)

  • Diesel fuel only.
  • Exhaust must vent outside and must not leak — carbon monoxide risk if not installed correctly.
  • Keep combustibles away from the exhaust; it runs extremely hot and needs clear space.
  • Don’t interrupt the cool-down cycle (don’t cut power) or you can cause excessive smoke and carbon build-up.

Before You Start (Especially First Use)

  1. Check fuel level and avoid running out — re-priming can take time.
  2. Confirm the heater’s air inlet/outlet vents are not blocked.
  3. Make sure your battery is healthy. The heater needs strong 12V supply, especially during ignition.

How to Turn the Heater On

  1. Short press the Power button to start.
  2. On startup, the heater runs a preparation cycle (about 3 minutes). You’ll then see a flame icon and feel heat from the duct once combustion starts.

Choosing a Heating Mode (MZ Controller)

Option A: Manual Heat (ROOM) — Set a steady heat level

  1. With the heater running, short press the round dial to toggle modes until the screen shows ROOM.
  2. Turn the dial to set the output level (Level 1 to Level 10).

Option B: Thermostat Mode (SET) — Maintain a target temperature

  1. Short press the round dial to toggle until the screen shows SET.
  2. Turn the dial to choose your target temperature (8°C to 36°C).
  3. The heater will automatically increase/decrease output to reach the target. When it reaches the set temp, it can stop burning fuel, then re-ignite when the temperature drops a few degrees.

How to Turn the Heater Off (Important)

  1. Short press the Power button to shut down.
  2. Allow the shutdown/cool-down cycle to complete (typically 3–5 minutes).

Priming the Fuel (First Install / After Running Out of Fuel)

If the heater is new, has been drained, or has run out of fuel, you may need to prime the fuel line so diesel reaches the heater.

  1. Turn the heater on.
  2. Enter the EN menu: press and hold the Settings button, then press and hold the Power button at the same time. Release when the screen shows EN00.
  3. Rotate the dial to EN07 (prime). The display shows “-P-”. The pump runs for 90 seconds and then moves to normal start mode.
  4. If fuel hasn’t arrived after the first prime cycle, you can run prime again.
  5. Don’t over-prime — it can cause excessive exhaust smoke.

Useful Settings on the MZ Controller

  • F0: Clock (may reset if power is disconnected)
  • F1: Timer start time (auto start)
  • F2: Timer running time (auto stop after set duration)
  • F3: Toggle timer function on/off
  • F4: Language & voice (or no voice)
  • F5: Temperature calibration (-9°C to +9°C)
  • F6: Fuel tank size (enables the fuel-remaining indicator). After refuelling, hold FUEL LEVEL RESET for 7 seconds while heater is on.
  • F7: Pump rate 16U/22U (many MZ controllers are preset to 22U)
  • Bluetooth: app name often shown as airheaterble with default password 1234 (if unchanged)

Troubleshooting (Common Fault Codes)

E01 / E02 — Startup failure / No fuel

  • Check the tank has diesel and prime if needed.
  • Inspect fuel line, clamps, and fuel filter; check for air leaks/blockages.
  • If it hasn’t been used for months, consider fuel contamination and try fresh diesel.

E03 — Power / voltage supply issue

  • Ensure battery voltage is in range (12V heaters commonly require stable voltage during ignition).
  • On startup/shutdown the glow plug load can draw higher amps — connect directly to a healthy battery to reduce voltage drop.

E09 — Overheating

  • Check heater air inlet/outlet for obstructions and ensure warm air can flow freely.

Tip: The controller’s EN menu often includes a “last error code recorded” screen (commonly EN01) which can help diagnose intermittent faults.

Simple Maintenance

  • Monthly: run the heater on high for at least 15 minutes to keep everything circulating.
  • Keep the exhaust as short as practical to help reduce carbon build-up.
  • Avoid running out of fuel to reduce the need for re-priming.
  • Always allow the full shutdown cool-down cycle to complete.