Error C6 215

Safety precautions:

1. If you smell gas, get everyone out of the building immediately and call the gas emergency number. Do not stay in the property and do not try to fix anything.

2. Do not open the boiler casing, attempt electrical measurements, or replace gas-related components unless you are a qualified Gas Safe engineer. Working on gas appliances is dangerous and illegal for unqualified people.

3. Avoid repeated resets. Repeatedly forcing the boiler to run while a safety fault exists can create unsafe conditions or mask the real issue.

Initial homeowner checks you can do (safe, non-intrusive):

1. Note the exact fault code and any other codes or lights shown on the boiler display. Take a photo for the engineer.

2. Turn the boiler off at the normal control or on the room thermostat and wait 5–10 minutes, then turn it back on and observe whether the C6 215 returns. One power cycle can clear transient electronic faults.

3. Check the external flue terminal is clear of obvious debris, nests, snow, ice or other blockage. A blocked flue can change fan loading and cause faults.

4. Check external condensate pipe (if visible) for freezing or blockage in cold weather — blockages can affect operation. If frozen, thaw carefully following safe guidance (do not pour hot water directly into plastic pipe joints; pour warm water gradually).

5. Check around the boiler for signs of water ingress or damp at the fan connector or wiring (water or corrosion can cause faulty signals). Do not attempt to open the boiler to inspect internal connectors.

6. If the boiler was recently worked on or a power surge occurred, record that information as it may help diagnosis.

If initial checks and a reset do not clear the fault, contact a Gas Safe registered engineer. What the engineer will do (diagnostic and repair steps they will follow):

1. Verify fault history and reproduce the fault safely in service mode. Record exact codes and service menu data.

2. Inspect the fan assembly and impeller for mechanical damage, shaft play or seized/worn bearings. Replace the fan if bearings are worn or impeller damaged.

3. Check the fan electrical connector, harness and cable for corrosion, damage or loose pins. Repair or replace the plug/cable if faulty.

4. Measure supply to the fan and the fan speed/signal at the control board to confirm whether the motor or the PCB/speed sensing circuit is at fault.

5. Inspect associated sensors and the air pressure switch that monitors flue/airflow to ensure correct functioning and no restrictions in the flue.

6. Check for moisture ingress or blocked condensate/drainage that could affect electronics and clear or repair as required.

7. If the fan and wiring are OK, test and if necessary replace the control PCB or burner control unit if it is producing erroneous fan speed readings. Restore any service settings after replacement.

8. After repair, the engineer will run the boiler, verify correct fan speed and safe flue evacuation, clear the fault code and confirm normal operation.

Important final notes:

1. Because this fault involves the combustion and flue system, it should be repaired by a Gas Safe registered heating engineer. Do not attempt internal electrical or mechanical repairs yourself.

2. When you call the engineer, give them the boiler model (Worcester Bosch GB162), serial number if available, the exact fault code (C6 215), a brief description of any recent events (power cuts, storms, freezing) and the photos you took of the display. This speeds diagnosis and helps ensure they bring the right parts.

3. If the boiler locks out and you need heating or hot water, the engineer can advise whether a temporary safe workaround is possible, but safety limits will often prevent a temporary run until the fault is fixed.