Your issue is probably related to the measuring PCB in the controller. Please follow the three steps below to determine if the measuring PCB is defect and return to us with your findings:

  1. Open the circuit breaker of the generator with the controller in question. 
  2. With the generator running and the breaker open. Go to view “V1” on the DEIF display and read out the busbar and generator voltages to see if there are differences in the voltage readings on the three phases. When cursor is under V1 you can scroll up and down using the navigation arrows.
  3. Measure the generator (terminal 79, 81 and 83) and busbar (terminal 85, 87 and 89) voltages on the controller terminals and compare with the display readings.


If the above voltmeter readings show different values compared to the readings on the display, the measuring PCB is worn-out, and we can provide you some options on how to move on from here.  See GPU-3, PPU-3 and PPM-3 faulty uP PCB request : Support ( for further actions.


DEIF products are based on electronics, which normally have an expected lifetime of minimum 10 years at operating temperatures up to 40°C. For higher temperatures lifetimes for electronics will in general be halved for every 10°C the temperature exceeds the 40°C.