Error FD 231

Safety precautions:

- If you smell gas at any time, do not touch the boiler. Open windows, turn off the gas supply at the meter if safe to do so, leave the building and call the gas emergency number immediately.

- Do not remove the boiler casing or touch internal components unless you are a Gas Safe qualified engineer. Mains voltage and gas components are hazardous.

- Work safely around electricity: switch off the mains before inspecting fused spurs or replacing fuses, and if you are unsure about electrical work, call a qualified electrician.

Initial checks a homeowner can do:

1. Check other mains-powered items in the house to confirm if there was a general power cut. If there was a recent power cut, wait until power is stable.

2. Check the boiler’s isolator switch or fused spur (usually next to or under the boiler). Ensure it is switched on and the local fuse hasn’t blown. Only replace external fuses when you are confident and using the correct type and rating.

3. Check the consumer unit (fuse box) for any tripped MCBs or blown fuses. Reset a tripped breaker and see if the boiler powers up.

4. Look at the boiler display for the FD 231 code and any additional cause code or a flashing triangle. Press the spanner/return or quick-info button (model dependent) to view a cause code if shown — note any numbers to tell the engineer.

5. Try a controlled reset: press and hold the boiler reset button (or follow the model-specific reset method from the manual) for about 3 seconds, then wait a few minutes for the boiler to attempt to restart.

6. If reset restores normal operation, observe the boiler for a while to ensure it remains stable. If the FD 231 does not return, the issue was likely a transient power interruption.

Specific diagnostic and next steps if the code persists:

1. If the boiler has no power but the rest of the house does, check the fused spur feeding the boiler. If that external fuse is blown, replace it with the correct rating. If a new fuse blows immediately, do not continue—this indicates an electrical fault; isolate the boiler and call a qualified electrician and Gas Safe engineer.

2. If the consumer unit and fused spur are OK but the boiler still shows FD 231 or won’t power up, do not open the boiler. The problem may be internal (internal fuse, wiring, PCB or lockout condition). These require a Gas Safe engineer to diagnose and repair.

3. If the boiler resets but repeatedly returns to FD 231, document when it happens (time, whether it followed a power dip, any other appliance issues) and call a Gas Safe engineer. Repeated power-related lockouts can indicate failing internal components or unstable supply.

4. If any other fault codes appear alongside FD 231, record them and tell the engineer—this helps diagnosis (for example, flame, fan or sensor codes indicate different underlying faults).

When to call a professional:

- Call a Gas Safe registered heating engineer if the simple checks and a reset do not clear FD 231, if the boiler has no power while the house supply is OK, or the code keeps returning. Do not attempt internal electrical or gas repairs yourself.

- If you suspect an electrical supply problem to the property (frequent dips/trips), contact a qualified electrician or your supply distributor in addition to booking a Gas Safe engineer for the boiler.

What to tell the engineer:

- Exact error code (FD 231) and any cause code shown in the info menu, whether the reset cleared it, whether the problem happened after a known power cut, and whether any fuses or breakers were tripped. Take a photo of the display if possible.

Final note:

FD 231 most commonly follows a mains interruption and is often cleared by a reset, but persistent or recurring FD 231 points to an underlying electrical or control fault that needs a qualified Gas Safe engineer and possibly an electrician. Do not open the boiler or attempt internal repairs yourself.