For posterity. The problem is an error in Junkers Carapur Midi stoves (in my case ZWB24-1RE23S5300), but each ZWB24 series has the same design when it comes to this error. Error d5 is caused by accumulation of condensate (two options here - dirty siphon or condensate drain), damage to the condensate accumulation sensor (or short circuit of the cables to this sensor) or damage to the electronics itself - but this is rare. The most common cause is contamination on the sensor itself, catching moisture that shortens it, or corrosion of the sensor itself, which leads to the same error. All you need to do is clean or replace the sensor itself - the cost at the beginning of 2023 is approximately PLN 65. This can be solved TEMPORARILY, but only if we are sure that the condensate is drained without any problems (you need to clean the siphon and the drainage pipe) and check whether water is not rising in the siphon. We then disconnect one of the connectors on the condensate accumulation sensor (located in the upper part on the right side under the top cover), usually two blue wires or a blue and black wire. After disconnecting, the problem with the d5 code will disappear, but the failure will remain - no, this is not a complete solution to the problem. I DO NOT RECOMMEND leaving it without cleaning or replacing the sensor - this may cause greater problems (costs) if the condensate drain is clogged, because the condensate will get into the condensing unit and may leak onto the stove and damage the electronics and other servo mechanisms.
