Daikin Altherma fault EC-00

What it means

Domestic hot water tank thermistor measures a too high temperature.

Likely causes

1. Increased water temperature due to an external heat source
2. Faulty domestic hot water tank thermistor
3. Faulty hydro PCB
4. Faulty room thermistor
5. Deviation of thermistor (higher temperature measured than actual).
6. Bad contact between sensor and pipe
7. Deviation of outlet water after backup heater thermistor (lower temperature measured than actual)
8. Deviation of thermistor (lower temperature measured than actual)
9. Incorrect refrigerant charge
10. Faulty expansion valve control
11. Faulty suction thermistor
12. Blockages in refrigerant circuit
13. Faulty discharge pipe thermistor
14. Domestic hot water tank thermistor measures a higher temperature than actual (component failure)

Where to start

1. Check the water circuit for an external heat source (see 4.3 Water circuit)
2. Perform a check of the domestic hot water tank thermistor (see 3.21 Thermistors)
3. Perform a check of the hydro PCB (see 3.12 Hydro PCB)