Hello everyone.
I will probably get the Vaillant "RecoVair 275" in my house. Before that, I tried to find some experiences online to see if the system has any major defects. If you can even say that. Overall, most "end customers" seem to be satisfied. Except for the failure of a circuit board. To save you an expensive troubleshooting, I’m copying the error solution from another forum here. I hope this helps you....
I also had the same error. Sudden total failure of the system. Remote control showed nothing anymore. First, I also measured the voltage on the bus (thanks for the tip!). Since it was not 5V, the new main board was ordered: €257.30 - that hurts. But at least the device worked again with it. Now I had the old board on the desk and was about to dispose of it when curiosity got me. The result of a quick inspection was that the 25V electrolytic capacitor (C4 on the board: a can, 20 mm high and 12 mm diameter - I can’t upload a photo right now) was swollen, or rather the bottom lid was already popping out. This happens when the capacitor dries out - the liquid electrolyte inside the capacitor has diffused out. This happens faster or slower depending on the temperature of the capacitor during operation. The original capacitor is a CapXon from the KM Series Standard 105°C. According to the datasheet, this type has a lifetime of 2000 hours when operated at 105°C. The lifetime doubles according to the 10K rule for every 10°C below this nominal temperature. The external temperature of the power supply, which is located directly next to the defective electrolytic capacitor, measures over 70°C in operation with a contactless thermometer. The uncertainty of the thermometer might be large, so let’s agree on 65°C (which is easier to calculate :). Since this is 40°C below the nominal temperature, the expected lifetime is 2000h x 2 x 2 x 2 x 2 = 32000h. As one year has about 8000h and the device runs more or less continuously, I come to 4 years that the capacitor can only last under these conditions. Our system is now 5 years old and the systems mentioned above in this thread also. Next, I ordered a new capacitor at Conrad with the following data:
Capacity: 1000µF
Rated voltage: 25V
Lead spacing: 5mm
Max. temperature: 125°C - with that it should last 4 times longer than the original part
Cost of this luxury capacitor: €1.29 (the one with 105°C like the original part is already available for 21 cents)
After replacing this one capacitor, the system runs again with the old board. The data from the memory is also still there.
I conclude that the layout engineer of this board did not consider the temperature problem. I do not want to accuse anyone of intent here. I will ask Vaillant what they say about it. This is definitely not a quality feature and there should be widespread failures after a few (4-6) years, only to buy the next board with the same problem for €250 (+ technician cost). That's why service technicians always have the board with them right away...
Hello,
I also had problems with the control of the ventilation system. After I disconnected the system from power for about half a day over New Year's and wanted to put it back into operation, there was no display on the remote control anymore and the fans ran at full speed. Thanks to Sonnenhaus2’s tips, I took a closer look at the board. Visually, the electrolytic capacitors looked okay. However, only a voltage in the mV range appeared at the output for the remote control. I replaced both capacitors (1000µF 50V & 25V). Now the system and remote control are working again. For your information - there are about 20V at the output to the remote control (fluctuates a bit, surely because of some eBUS signal overlay). I previously also had problems with the bypass control, which I have turned off for months so that the system would keep running at all. Now that works again too!
Really great how penny parts are installed here that then precisely expire right after the warranty period. But it’s surely all just coincidence...
There is still one phenomenon on the board - but unfortunately I can’t say if that was already there before the failure. There is a quiet clicking shortly after switching on that does not stop. I suspect it comes from the relay of the error out switch. It is not disturbing and cannot be heard from outside when the board is installed. But maybe one of you has a tip.