Daikin Altherma fault E5-00

What it means

Compressor overload is detected.

Likely causes

1. Closed stop valve in the refrigerant circuit
2. Faulty discharge pipe thermistor or connector fault
3. Faulty outdoor unit fan motor
4. Faulty compressor or miswiring of the compressor power supply cable
5. Faulty expansion valve
6. Faulty 4-way valve
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. Bad contact between refrigerant loop and inverter heat sink
14. Lack of refrigerant
15. Faulty suction thermistor
16. Blockages in refrigerant circuit
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 that all stop valves of the refrigerant circuit are open
2. Perform a check of the discharge pipe thermistor
3. Perform a check of the outdoor unit fan motor