Solar · Error codes
What do Sunsynk codes F35, F42, F43, F47 and F48 mean?
Short answer
They are grid protection codes: F35 no grid (power cut or tripped supply), F42/F44 low voltage, F43 high voltage, F47 over-frequency and F48 under-frequency. The inverter disconnects to meet grid rules and reconnects when the supply is normal (Sunsynk fault document, March 2024, checked 24 September 2026). Frequent trips need installer and DNO checks.
Last checked 24 September 2026 · 1 source
In more detail
- Older ECCO manual v3 wrongly labels F48 as 'DC bus bar voltage too low' - F56 is the low-battery code.
- Check for power cuts and tripped breakers first.
The facts, dated
- 01Sunsynk 2024 document defines F48 AC_UnderFreq_Fault; ECCO manual v3 description table conflicts.
manufacturer · UK · checked 24 September 2026 · hg-technical.herholdts.co.za
Sources
- hg-technical.herholdts.co.za — hg-technical.herholdts.co.za/Technical/02%20Sunsynk/Technical/Fault%20Codes%20Ca…
Last checked: 24 September 2026