Appliance hub
Ideal Boiler Fault Codes
Browse the available Ideal boiler fault codes in one place, then open the exact code page for the documented meaning, evidence limits and safe next steps.
Definitions can vary by model and region. Some codes remain unconfirmed; check the complete display, exact model and the page's sources before taking action.
Browse the parent brand page: Ideal or compare across brands in the boiler codes across brands.
Fault codes
18
Code categories
9
Guides linked below
3
Code pages to start with
Browse code categories
Codes awaiting confirmation
5 pages in this category. Open C6 as one example and check its model limits.
PCB and control codes
3 pages in this category. Open F9 as one example and check its model limits.
sensor codes
3 pages in this category. Open F5 as one example and check its model limits.
ignition codes
2 pages in this category. Open L2 as one example and check its model limits.
fan and flue codes
Open F3 for the documented meaning and its limits.
flame-loss codes
Open F2 for the documented meaning and its limits.
Code categories in this library
Counts refer to published code pages, not how often an appliance develops a fault.
unconfirmed (5)
PCB and control (3)
sensor (3)
ignition (2)
fan and flue (1)
flame-loss (1)
More code pages
F9 meaning and guidance
PCB fault on the documented Instinct2 models
C6: model confirmation needed
Meaning unconfirmed; exact model documentation is required
F5 meaning and guidance
Return-thermistor fault in Ideal’s documented F5 guidance
C0 meaning and guidance
BCC activation fault
C2 meaning and guidance
BCC chip fault
C5: model confirmation needed
Meaning unconfirmed; exact model evidence required
C7: model confirmation needed
Meaning unconfirmed; exact model evidence required
D4: model confirmation needed
Meaning unconfirmed; exact model evidence required
F1 meaning and guidance
Low water pressure
F2 meaning and guidance
Flame loss or ignition fault
F3 meaning and guidance
Fan fault
F4 meaning and guidance
Flow-thermistor fault
All fault codes in this cluster
18 code pages currently available for this brand and appliance. A severity label does not establish whether an appliance is safe to use.
| Code | Meaning | Issue type | Severity |
|---|---|---|---|
| C0 | BCC activation fault | pcb control | Not assessed |
| C2 | BCC chip fault | pcb control | Not assessed |
| C5 | Meaning unconfirmed; exact model evidence required | unconfirmed | Not established |
| C6 | Meaning unconfirmed; exact model documentation is required | unconfirmed | Not established |
| C7 | Meaning unconfirmed; exact model evidence required | unconfirmed | Not established |
| D4 | Meaning unconfirmed; exact model evidence required | unconfirmed | Not established |
| F1 | Low water pressure | pressure level | Not assessed |
| F2 | Flame loss or ignition fault | flame loss | Not assessed |
| F3 | Fan fault | fan flue | Not assessed |
| F4 | Flow-thermistor fault | sensor | Not assessed |
| F5 | Return-thermistor fault in Ideal’s documented F5 guidance | sensor | medium |
| F6 | Outside-sensor fault | sensor | Not assessed |
| F9 | PCB fault on the documented Instinct2 models | pcb control | Not assessed |
| HF | Meaning unconfirmed; exact model evidence required | unconfirmed | Not established |
| L1 | Flow-temperature or no-flow lockout | overheat | Not assessed |
| L2 | Flame loss or ignition lockout | ignition | Not assessed |
| L5 | Excessive resets in the checked Ideal FAQ | power control | Not assessed |
| L6 | False-flame lockout | ignition | Not assessed |
Useful guides
Boiler Fault Codes: When to Stop and Call a Professional
First separate an emergency from a routine fault. A code needs the exact model and full display; it cannot by itself establish a safe reset or identify a part to replace.
When to Call an Appliance Engineer
Use the exact manual for permitted owner checks. Recurring faults, unsafe symptoms and work inside the appliance need appropriate professional help; emergencies need immediate action.
Why Your Boiler Keeps Losing Pressure
Use the pressure target and filling instructions for your exact boiler and installation. Repeated pressure loss needs investigation; a low reading alone does not identify a failed component.