An Air Heater for Bush Camping

A space heater is a necessity for winter camping most places in Australia. And the best for us appears to be an air heater running off the vehicle's diesel fuel tank.

The Eberspächer Airtronic diesel heater handled by Dometic in Australia is a high quality system. After consulting Dometic's Technical Manager in Brisbane, we purchased a 2-outlet D2 kit with rheostat controller from CARAC .

The specifications for the Airtronic D2 are:

During installation, we replaced the rheostat controller with a mini-controller, from Autoteile-Discount24.de, because of constraints on location and aesthetics: the rheostat controller requires a lot of clear depth behind the facia, and it looks more in place in a bus or truck.

The Heater in Operation

The following information is extracted from a document (2.3 MB) on the Espar Web Site. Espar is the Canadian arm of Eberspächer. The document also contains good installation, troubleshooting and parts information.

On start up the indicator light on the controller illuminates and the following sequences take place:

• The control unit does a systems check of the glowplug, flame sensor/temperature sensor, fuel metering pump and control unit
• Glowplug is energized and starts preheating the combustion chamber
• Hot air fan/blower starts slowly and begins to accelerate
• After a delay of approx. 20 s the fuel pump delivers fuel
• Ignition will take place as the fuel/air mixture begins to burn
• Hot air fan/blower speed and fuel delivery are slowly increased
• Once flame sensor has detected a flame the glowplug will switch off, after approx. 15 s
• After another 120 s, the heater will have reached maximum power.

The temperature is monitored constantly at the heater's hot air inlet.

• This temperature is compared to the set temperature on the adjusting dial of the controller
• The heater cycles through Boost, High, Medium and Low heat modes to maintain the desired temperature
• If the desired temperature is exceeded while the heater is operating in Low heat mode the heater will switch into "standby" mode
• The heater will re-start once heat is required again.

Once switched off manually, the heater begins a controlled cool down cycle.

• Indicating light(s) on controller will go off
• Fuel pump stops delivering fuel
• The glowplug is re-energized for a 40 s after-glow to burn off any combustion residue
• The hot air fan/blower continues to run for 4 min and automatically switches off.

My experiences installing the heater in the A'van Applause 500 are given in the Installation Web Page.

During sustained use, it is important to not allow the heater to switch on and off. Otherwise, uneven temperatures and high current consumption during startup and shutdown occur each time the heater cycles. By adjusting the thermostat down and if necessary admitting some outside air, an operating point can be found where the heater runs at a low level all the time.

The Airtronic D2 heater operates very well. We are pleased.

Fault Lockout Mode — a non-issue

There are basically two operational errors that can trigger fault mode:

• failure to start (no fuel, no combustion air)
• over heating (air intake covered, air outlet covered).

For the system to lock the user out, it would have to log 255 consecutive errors of the same type. [However, if the system logged 254 consecutive failures to start and the then 1 over-heat failure, the 254 failures to start would be deleted and the count would begin again.] So, yes, it is possible for the system to lock up, but this would have to be extremely rare.

As for running out of fuel, restarting with a refilled tank is simple since the fuel metering pump is self-priming.

Reference: http://www.bushtrackerownersforum.com/viewtopic.php?t=938

Heavy Maintenance

This Web site has a lot of information (with pictures) on maintenance, fault finding and repair of the Airtronic Heaters.

LINKS

• Eberspächer http://www.eberspacher.com
• Espar http://www.espar.com
• Dometic Australia http://www.dometic.com.au
• CARAC http://www.carac.com.au
• Autoteile-Discount24 http://www.autoteile-discount24.de

Eberspächer Airtronic D2 Diesel Heater

The Airtronic D2 2-outlet kit is similar to this single outlet kit but with a "Y" duct fitting and extra ducting. (Photo courtesy of David Nye)

The table in the Applause is on a raised floor. The Airtronic D2 is installed in the floor behind the driver's seat, and hot air inlet and outlet are pointed into the main passageway.

The Airtronic mini-controller is conveniently located below the Trauma hot water controls at the bedside. A clock with date, thermometer and touch-pad light is also located there.

A yellow stoneguard hides the fuel metering pump and filter for the Airtronic heater

The only visible sign of the diesel air heater: twin exhausts!