Error F0 237

Safety precautions:

- If you smell gas, evacuate the property immediately and call your local gas emergency number. Do not operate electrical switches or the boiler.

- Do not open the boiler casing or attempt internal electrical or gas repairs unless you are a qualified, registered engineer. Live electrical work and gas equipment are dangerous.

- If the boiler shows signs of burning smell, smoke, or water leaking into electrical areas, isolate the electricity at the consumer unit and call a Gas Safe engineer.

Initial homeowner checks you can safely do:

1) Record what you see: write down the exact fault code (F0 237), any other codes or flashing lights, when it started, and any recent events (power cut, storms, service work).

2) Single reset: try one reset of the boiler using the manufacturer’s reset button or via the control panel. Wait 5–10 minutes after reset for the boiler to attempt a restart. Do not repeatedly reset the boiler; one attempt is acceptable for diagnosis.

3) Check mains power and fuses: ensure the boiler is receiving mains power (other appliances working, consumer unit fuse not tripped). If the boiler lost mains briefly it can cause control errors.

4) Check external controls: confirm the room thermostat, programmer/timers and any wireless controls are calling for heat and have batteries/power. Disconnecting or incorrect signals from external controls can sometimes appear as internal errors.

5) Check system pressure: note the pressure gauge. If pressure is very low (below ~0.8–1.0 bar) top up the system to the recommended level per the user manual (follow your boiler manual or manufacturer video for filling instructions). Low pressure can cause various fault codes; however F0 237 is generally an internal fault, but it’s worth ensuring the basic operating conditions are correct.

6) Look for obvious external issues: check for visible water leaks around the boiler, wet or corroded wiring to external controls, or blocked condensate pipe (in freezing weather). Photograph any visible damage and the boiler display to show the engineer.

Specific diagnostic steps and what to tell the engineer:

1) If the reset clears the fault and the boiler runs normally for a while, still note the occurrence and monitor closely. Intermittent internal errors often indicate developing electronic or connection faults.

2) If the fault returns or persists after one reset, stop further resets and prepare to call a qualified engineer. Before they arrive, note any other error codes, LED flash patterns, and exactly what happened before the fault (power outage, service, freeze, heavy rain, etc.).

3) Do not attempt to test or disconnect ignition leads, the gas valve, PCB connectors, or internal sensors yourself. These components are live or gas-related and must only be checked by a Gas Safe engineer.

4) If you are a qualified engineer: check wiring and plug connections to the PCB and burner control/KIM module, examine the PCB for burn marks or damaged components, run the diagnostic service mode and log failing tests (sensor tests, ignition sequence, gas valve operation). Typical engineer actions for F0-type internal errors include checking connector continuity, replacing a faulty control unit or KIM/plug-in module, or replacing a failed gas valve or ignition module if verified faulty.

When to call a professional and what to request:

- Contact a Gas Safe registered engineer (or the manufacturer service team) if the fault remains after the single reset and basic checks, or immediately if you smell gas, see smoke, or have leaks. Provide the engineer with the exact model, serial number, the F0 237 code, any other codes or LED flash patterns, a description of recent events, and photos of the display and surrounding installation.

- Ask the engineer to check the boiler control PCB, burner control unit/KIM, gas valve and wiring/connectors as part of their diagnostic. Because F0 237 is an internal control-type fault, replacement of the control board or a module may be required and should be performed by a qualified technician.

Important notes:

- Do not repeatedly reset the boiler; repeated resets can mask the problem or cause further issues.

- Do not attempt internal electrical or gas repairs unless you are a competent, registered engineer.

- No repair cost estimates are provided here; the correct remedy depends on the engineer’s diagnosis (faulty connector vs. PCB vs. gas valve/component).