Overview
F0 287 on a Worcester Bosch GB162 indicates an internal fault with the burner control unit (sometimes called the KIM). In Worcester fault-code terms F0 signals an internal electronic/control error and the three-digit cause number narrows it down to the burner control module itself. This means the boiler has detected a problem inside the ignition/burner control electronics and has usually locked out to prevent unsafe operation. Severity is moderate to high: the boiler will likely not operate until the fault is cleared and, because this involves burner control/electronics, it is not a routine DIY repair. The fault can be caused by a defective control module, water/wiring damage, loose connectors, software/watchdog failures or an incorrect replacement module fitted previously. Homeowners can perform some basic checks and a single reset attempt, but diagnosis and any replacement of the KIM/control board should be done by a qualified Gas Safe engineer.
Possible Cause: The burner control unit, or KIM, has an error.
Troubleshooting Steps
Safety precautions:
1. If you smell gas, do not operate switches or the boiler. Turn off the gas supply at the meter if you can do so safely, ventilate the area and call the gas emergency number and a Gas Safe engineer immediately.
2. If the boiler is in a locked-out state and there are signs of water leak, burning, scorched wiring, or heavy corrosion, switch the electrical supply to the boiler off at the isolator and do not attempt internal repairs.
3. Do not attempt to replace PCBs, ignition modules, gas valves or any gas-carrying components unless you are a Gas Safe registered engineer.
Initial homeowner checks you can safely do:
1. Note the exact fault code shown (F0 287) and any other codes or flashing triangles. Press the spanner/return button to view the three-digit cause code if available and write it down or take a clear photo of the display.
2. Check that the boiler has mains power: confirm the boiler isolation switch is on and other house circuits are working. A recent power cut or surge can trigger internal faults.
3. Try a single controlled reset: on GB162 press and hold the reset button or follow your manual (usually press and hold for about 3 seconds). Wait for the boiler to attempt a restart. If the fault clears and the boiler runs normally, monitor it for recurrence. Do not repeat resets more than once or twice if the fault persists.
4. Visually inspect (from outside only) around the boiler for signs of water leak, corrosion, damp at the base or wet wiring/connections. Also check for obvious damage to the flue area and for recent trades or work that might have disturbed wiring.
If the fault persists after the checks and one reset:
1. Record and photograph the display showing F0 287 and any cause codes, plus the boiler serial/model plate and any visible damage. Also note the sequence of events (power cut, heavy rain, freezing conditions, recent service, etc.).
2. Contact a Gas Safe registered Worcester Bosch engineer and give them: boiler model (GB162), serial number, exact fault code F0 287, any cause code from the info menu, history (power loss or water ingress), and the photos you took. This helps speed diagnosis.
What the engineer will typically do (for information only):
1. Isolate electrical and gas supplies, remove the outer cover and inspect the burner control box/KIM for water ingress, corrosion, burnt components or loose connectors.
2. Check connector pins and ribbon cables, measure voltages and signal lines, and test related sensors and the heat control module compatibility. They may check watchdog/relay/resistor circuits referenced in service literature.
3. If the control module/KIM is faulty or the watchdog/software error cannot be cleared, the engineer will replace the burner control unit or PCB with the correct Worcester part and re-run commissioning and safety checks.
Important final notes:
1. F0 287 is not a normal do-it-yourself repair. After basic safe checks and one reset attempt, call a Gas Safe engineer. Repeated resetting can mask a real safety fault and may lead to further damage.
2. If there is any sign of gas smell, severe water ingress or electrical burning, isolate power and gas and call emergency services/Gas Safe immediately. When you call a service engineer, provide the exact code and any cause code and the circumstances leading to the fault to reduce diagnostic time.
Helpful Resources
Boiler Manual
Download the official PDF manual for the Worcester Bosch GB162 Boiler.