Daikin Altherma fault A5-00

What it means

Pressure is too high in heating / domestic hot water, too low in cooling.

Likely causes

1. Water flow is too low
2. Closed stop valve in the refrigerant circuit
3. Clogged refrigerant circuit
4. Refrigerant overcharge or shortage
5. Non-condensables and/or humidity in the refrigerant circuit
6. Faulty refrigerant pressure sensor
7. Poor water flow through high pressure side plate heat exchanger
8. Incorrect refrigerant charge
9. High pressure switch confirmed faulty during checking procedure

Where to start

1. Check the water flow
2. Check that all stop valves of the refrigerant circuit are open
3. Check if the refrigerant circuit is clogged