HVACopediaRinnai combi boiler error codes
42 codes with causes and test steps.
| Code | Meaning | Severity |
|---|---|---|
| 021 | DHW continuous operation time exceeded | Low |
| 100 | Air intake/exhaust blockage or full condensate trap | Critical |
| 110 | Ignition failure | High |
| 120 | Flame failure (flame lost during operation) | High |
| 140 | Overheat switch tripped (heat exchanger overheating) | Critical |
| 150 | Venturi control fault | High |
| 161 | High DHW outgoing water temperature | Critical |
| 170 | Venturi blockage / position mismatch | High |
| 180 | Gas valve air/fuel adjustment limit reached | High |
| 190 | Electrical grounding / short in DC circuit | High |
| 210 | Data transfer error | Medium |
| 220 | Gas valve position not detected (reed switch) | Medium |
| 250 | Condensate pump switch tripped (accessory) | High |
| 303 | Secondary system thermistor fault | Medium |
| 310 | Freeze protection thermistor fault | Medium |
| 321 | Outgoing (DHW) water temperature thermistor fault | Medium |
| 331 | Plate heat exchanger thermistor fault (DHW) | Medium |
| 341 | DHW inlet thermistor fault | Medium |
| 353 | CH supply thermistor fault | Medium |
| 363 | CH return thermistor fault | Medium |
| 380 | Exhaust thermistor fault | Medium |
| 393 | Outdoor temperature sensor fault | Medium |
| 400 | Water pressure sensor communication fault | Medium |
| 430 | High or low system water pressure | High |
| 443 | Low water cut-off (LWCO) activated | High |
| 520 | Gas solenoid valve circuit – flame after valve close | Critical |
| 540 | High exhaust (flue gas) temperature | Critical |
| 610 | Combustion fan motor speed fault | High |
| 631 | DHW recirculation pump – insufficient flow | Medium |
| 651 | Water flow control valve fault | Medium |
| 661 | Bypass valve fault | Medium |
| 670 | Three-way valve fault | Medium |
| 681 | DHW supply temperature abnormality | Medium |
| 700 | PC Board fault | High |
| 710 | Gas solenoid circuit – valve position mismatch | High |
| 720 | Flame rod fault | High |
| 763 | 0-10V external control input over-voltage | Medium |
| 890 | Freeze condition detected | High |
| 999 | PC Board / software mismatch | High |
| FFF | Maintenance performed marker | Low |
| LC | Lime condition – flush plate heat exchanger | Low |
| SS | Service Soon reminder | Low |
Models covered
IP060160CIP090099CIP090160CIP090199CIP120199CIP150199CIP175199CIP199199C
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.