Daikin 8H-02 fault code
Daikin Altherma heat pumps
What it means
Overheating mixed water circuit (thermostat)
The mixed circuit's safety THERMOSTAT operated. This is a hard safety device, not a sensor reading — something let the circuit get genuinely hot.
UK models this code applies to
From the Daikin service literature we hold (Daikin Altherma 3 M installer reference guide 4P685228-1B §14.4.2) — not a scraped list.
Altherma 3 M class 4 reversible (EBLA04E2V3)Altherma 3 M class 6 reversible (EBLA06E2V3)Altherma 3 M class 8 reversible (EBLA08E2V3)Altherma 3 M class 4 heating only (EDLA04E2V3)Altherma 3 M class 6 heating only (EDLA06E2V3)Altherma 3 M class 8 heating only (EDLA08E2V3)Altherma 3 M class 9 reversible (EBLA09D3V3)Altherma 3 M class 11 reversible (EBLA11D3V3)Altherma 3 M class 14 reversible (EBLA14D3V3)Altherma 3 M class 16 reversible (EBLA16D3V3)Altherma 3 M class 9 heating only (EDLA09D3V3)Altherma 3 M class 11 heating only (EDLA11D3V3)Altherma 3 M class 14 heating only (EDLA14D3V3)Altherma 3 M class 16 heating only (EDLA16D3V3)Altherma 3 M class 9 reversible 3-phase (EBLA09D3W1)Altherma 3 M class 11 reversible 3-phase (EBLA11D3W1)Altherma 3 M class 14 reversible 3-phase (EBLA14D3W1)Altherma 3 M class 16 reversible 3-phase (EBLA16D3W1)Altherma 3 M class 9 heating only 3-phase (EDLA09D3W1)Altherma 3 M class 11 heating only 3-phase (EDLA11D3W1)Altherma 3 M class 14 heating only 3-phase (EDLA14D3W1)Altherma 3 M class 16 heating only 3-phase (EDLA16D3W1)Altherma 4 H 4 kW R290 (EPSKS04A)Altherma 4 H 6 kW R290 (EPSKS06A)Altherma 4 H 7 kW R290 (EPSKS07A)
Now the harder half: proving what caused it
8H-02 names a symptom, not a root cause. In the app, the same code opens a guided investigation: what to measure first, the expected values for your exact model, and an honest verdict — including “nothing in this machine is broken” when that's what the readings say.
Chase this code in the app →