Thanks @JGrimm for your detailed answer and photos. I’ve checked my heaters with the ohm-meter and impedances are really different, so looks like the heater itself is damaged (burnt, cracked or shorted). The left one reads 29.3 ohms while the right one just reads 11.2 ohms (exactly the same as yours, @fodi )
I attach the photo I’ve just sent to tech support in case it can help anyone else.
Thank you all, great community this one!!!
It worked! I simply exchanged the heater by itself with it’s wires from the heater 1 left side they sent me onto the right side! The heaters are exactly the same, on the right the fan is just upside down. But the only thing I needed to exchange was the heater!
Glad to hear you figured out the problem. I didn’t have an ohm meter in my apartment to check. Its at my parents house.
Great idea changing only the heaters!!!
Good to hear your problem is also resolved. I just wanted to write that heater #1 is on the left, while heater #2 is on the right on your picture (and you had problems with #2), but you figured it out as well. .