Daikin Altherma fault E8-00

What it means

Compressor running current exceeds standard value for 2.5 seconds, indicating an overvoltage/overcurrent condition on the power input.

Likely causes

1. Outdoor temperature is out of operation range
2. Faulty compressor or miswiring of the compressor power supply cable
3. Faulty inverter PCB
4. Faulty or disturbance of the power supply (power supply MUST be within range of nominal operating voltage ±4%)
5. Power drop
6. Short circuit
7. Faulty refrigerant pressure sensor
8. Poor water flow through high pressure side plate heat exchanger
9. Incorrect refrigerant charge
10. Compressor guard timer active
11. Special software control activated - water loop temperature is too low causing ONLY the backup heater to operate
12. Faulty compressor winding
13. Faulty expansion valve
14. Faulty suction thermistor
15. Blockages in refrigerant circuit
16. Faulty discharge pipe thermistor
17. Worn or damaged compressor dampers causing vibration/noise
18. Normal inverter control behavior when target temperature achieved
19. Flammable refrigerant remaining dissolved in compressor lubricant
20. Wrong assembly during repair
21. Excessive heat applied during brazing near compressor pipes

Where to start

1. Check the outdoor temperature
2. Perform a check of the compressor
3. Perform a check of the inverter PCB