The unit is a part of air-water heat pump Euronom Polaris with ExoTrol control unit. The issue presented itself as loud buzzing sound of two bypass relays not latching properly. Two large triacs (TPDV1240) that suppose to ramp up the voltage for a second was getting very hot as they had to carry all the motor current due to bypass relays not latching.
The solution was replacing all X-type capacitors as they had high ESR values and was way out of specs. I have replaced all 250v capacitors with 440v, to increase robustness.
The unit woks fine now but i suspect that the relays has been damaged to some extent and will not last very long. I will probably have to replace them as well.
As it was very difficult to find the correct relays for replacement i had to take some measurements in order to find some suitable replacements. After measuring coil voltage it seem to work at 48v AC, RMS. And after some googling i was able to find that probably relays in the circuit are Panasonic JM1AN-TMP-DC48V-F
Nesh TECH 