Platform & Control Notes
IBC uses different controllers: SFT/SFC show 'Fxxx' codes; older DC-series show short numbers (1, 4, 5, 8, 18, 19, sensor groups 10–14 / 20–24); newer SL 'G3' boilers show plain-text messages on a touchscreen. The code you see depends on your controller.
Model Families & Platforms
- SFT & SFC Series (Fire-tube combi/heating)
- DC Series (Dual-pass condensing)
- SL G3 Series (Touchscreen condensing)
Diagnostic Characteristics & Common Service Topics
IBC boilers utilize specific display codes and safety lockouts to protect the heat exchanger, combustion system, and hydronic loop. Everyday issues like pressure loss, flame sensing errors, or circulator faults trigger specific responses depending on the controller generation.
| Code | Meaning | Action Required |
|---|---|---|
| F004 / display 4 (No flame at start-up) | Boiler did not establish flame on start-up / ignition failure. | Confirm the gas valve is open; one reset is OK. If it repeats, call a pro to check gas pressure, igniter, and grounding. |
| F005 / display 5 (Flame lost during operation) | Flame established but lost during firing (poor/dropped flame signal). | Combustion fault — call a pro to check gas pressure under load, flame sensor, grounding, and flue/air piping. |
| F003 / flue sensor 18-19 (Flue gas temp too high) | Flue gas temperature exceeded its limit (or flue sensor open/short on DC). | Call a pro. Excess flue temperature usually means the heat exchanger needs cleaning — a combustion/flue issue. |
| F008 / display 8 (Incorrect fan speed) | Combustion fan not running at the commanded speed. | Call a pro. Fan/combustion component — a tech should check or replace the fan. |
| F010 / F011 (Heat-exchanger sensor S0) | Heat-exchanger temperature sensor (S0) out of range / open or shorted. | Tech task — check wiring and replace the heat-exchanger sensor. Not a homeowner repair. |
| DC 10–14 / 20–24 (Supply S1 / return S2 sensor) | Supply (S1) or return (S2) temperature sensor out of range; boiler won't light. | If it appears on a very cold start it may clear as the unit warms. Persistent S1/S2 faults need a pro to test/replace the sensor. |
| DC display 1 (Temperature too high) | Boiler water temperature too high / overheat hold. | Confirm the system isn't air-bound and zones/valves are open. If it persists, call a pro to bleed/check the pump and flow. |
| F018 (Flue/air duct blocked) | Air-intake and/or flue (exhaust) is obstructed. | Check the outside vent terminals for snow/ice/debris and clear obvious blockage. Internal vent work and re-light = call a pro (flue safety). |
Complete Error Code Library
For the complete searchable error-code lookup table for IBC equipment (including all 11 codes, exact lockout causes, and technician actions), visit the Phillips Hydronics Error Code Library.
Related Symptom & Diagnostic Guides
Sources & Documentation
- error-codes.json — https://www.ibcboiler.com/support/TIPortal/Content/Troubleshooting/SFT-199_models/Fault_codes_SFT_models.htm