Ten years after their release, Eberspacher / Espar Airtronic D2 and D4 have finally received an update. Named Airtronic S2 (D2L) and M2 (D4L), the two new heaters pack state-of-the-art technology in the same footprint, while significantly reducing fuel and electricity consumption. However, can they be called worthy successors to the last-decade’s heaters of choice? Let us find out.
Here are the links to Brand new high altitude kits:
The changes
Eberspacher Airtronic S2 and M2 sport a long list of features and changes from the previous version. We will go through them one by one to give you a clear picture of the improvements made. Short on time? You can find a quick summary at the bottom of the article.
Same case, easier installation
Espar Airtronic S2 and M2 come in a black plastic case identical to their predecessors. While that may not not sound like much of a change, the feat is actually impressive considering the number of improvements the heaters have received. It also means you will have no trouble replacing your old heater with a new one. Installation positions, mechanical interfaces, spare and repair parts all remain the same.
What has changed is the installation. With Eberspacher Airtronic D2 and D4, you had to do all the wiring yourself. This was both a blessing and a curse: you could easily adapt the wires to your vehicle; but it also led to installation errors, sometimes requiring a professional to install the heater for you. The wire harnesses of S2 and M2 come prepared for you, which greatly simplifies the installation process and reduces the need for specialised tools. And because the wires are generously long, you should have no issues fitting them to your vehicle.
Much quieter pump
The new pump contains one small but significant change for acoustic performance: a dampener. Thanks to it, the droning tick-tick sound has been greatly reduced. You will still hear some noise at startup, but during normal operation the heater will be barely audible.
Integrated altitude kit (up to 3,000 m / 9842.52 feet)
Espar Airtronic S2 and M2 include a new pressure sensor that continuously adjusts the speed of the air intake turbine and the frequency of the fuel pump. This ensures safe and efficient operation between the sea level and up to 3,000 meters / 9843 feet of altitude. That said, the old altitude kit promised safe operation up to 4,000 meters, so this remains one area wanting for improvements. Do not try to bring these heaters to the heights of Himalayas just yet.
Double the life span
Espar Airtronic S2 and M2 come with a new brushless motor, which is much more reliable than the one found in classic versions of Airtronic D2 and D4. The bearing design has been revised, making the part larger and sturdier. This has allowed Eberspächer to increase the life span of the new heaters to 5,000 hours—a huge improvement over the 2,000 to 3,000 hours advertised before. As a result, Airtronic S2 and M2 should last longer and lead to significant money savings in the long run.
Stepless control of heating performance
Besides reliability, another benefit of the brushless motor is its stepless control of the heat flow. The predecessors of Airtronic S2 and M2 had four pre-set power levels; now, the wattage of the heaters can be adjusted along the entire power range: from 850 watts / 2900BTU to 2,200 watts / 7500BTU for the S2 and from 900 watts / 3070BTU to 4,000 watts / 13650BTU for the M2. This makes it easier to adapt the heaters for your passenger compartment.
More environmentally friendly
The last but not least advantage of the brushless motor is its eco-friendliness. Stepless adjustment of power gives you more precise control over the heater’s performance, reducing waste. On the other end, manufacturers are now able to change power thresholds, which lets them better follow today’s or future environmental standards.
Starts at -46°C / -50.8°F
The previous generation of Airtronic heaters had serious issues starting from a temperature as low as -25° C / -13° F, even when running on arctic fuel. Though, to be fair, they worked without problems down to -50° C / -58° F once en route. Espar Airtronic S2 and M2 are able to start at much colder temperatures—on paper, at least. In reality, you should expect the real numbers to be slightly lower, depending on the fuel and additives used.
New and more intuitive Easystart Pro control
In many ways, the new Easystart Pro control resembles Easystart Timer. It is a high-end version that allows up to three programmable positions to control heating at a selected time or over a time range. However, its ergonomics have been completely revised and improved. You no longer need to be an engineer or have the manual in front of you to turn the heating on. Everything is simplified.
Another feature of note is that the Easystart Pro control incorporates a temperature sensor. It allows measuring the temperature directly in the passenger compartment where the control is located. There is no longer a need to put a remote sensor. However, the option to do so is still fully supported.
Airtronic S2 and M2 can be used with other controls, too. If you wish, you can install the Easystart Remote+ or any other older generation control instead. It is also possible to control the heater via a phone.
CAN bus protocol with simpler error codes
The new heaters incorporate the CAN bus protocol—the same as the one used for diagnosing many of the cars. This makes heating diagnostics even simpler with easy to understand error codes. When the time for servicing arrives, you (or your service technician) will come to appreciate this feature.
Here is a quick summary of the improvements in Airtronic S2 (D2L) and M2 (D4L):
- Same case, easier installation
- Much quieter pump
- Integrated altitude kit (up to 3,000 m -
- Life span doubled to 5,000 hours
- Stepless control of heating performance: from 850W to 2,200W (From 2900BTU to 7500BTU) for the S2 and from 900W to 4,000W for the M2 (from 3070BTU to 13650BTU)
- More environmentally friendly
- Starts at up to -46° C
- New and more intuitive Easystart Pro control
- CAN bus protocol with simpler error codes
Conclusion
It is time to return to our initial question: can Eberspächer Airtronic S2 and M2 be called worthy successors to Aitronic D2 and D4? In our eyes, absolutely. While not exactly revolutionary, they manage to improve on almost all of the important areas, providing a natural continuation to a respectable line of products. If you are looking for a quiet, reliable, and convenient air heater, Airtronic S2 and M2 should prove an enticing choice for protecting yourself from the elements.
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