Your Worcester Bosch boiler showing the C6 error code usually means there is a problem with the fan that helps remove combustion gases safely. This fault stops the boiler from running to protect your home.
What does the Worcester Bosch Boiler C6 Error Code mean?
The Worcester Bosch Boiler C6 Error Code means the fan is not running at the correct speed or there is an airflow issue. The boiler detects this and locks out for safety so harmful gases are not mishandled. You may lose heating until the problem is sorted.
It is a common alert on Greenstar models and often relates to the fan, flue or wiring.
What causes the C6 Error Code on your Worcester Bosch Boiler?
The C6 error code on your Worcester Bosch boiler is typically caused by fan problems, blockages in the flue or air intake, or electrical issues that affect fan speed. These stop safe airflow and trigger the safety response.
Faulty or Slow Running Fan
The fan that expels gases can wear out, seize or run too slowly after years of use. This is one of the most frequent causes of the C6 fault code.
How to Fix
- Try resetting the boiler once by pressing and holding the reset button.
- Listen for fan noise when the boiler starts. Unusual sounds or silence suggest a problem.
- If the error returns, call a Gas Safe registered engineer to test and replace the fan if needed.
- After repair, the engineer will check airflow and reset the system.
Blocked Flue or Air Intake
Leaves, debris, snow or nests can block the flue terminal or air intake, restricting airflow and making the fan work incorrectly.
How to Fix
- Safely inspect the external flue outlet for visible blockages.
- Clear any leaves or debris carefully without damaging the pipe.
- In winter, check for ice and thaw gently if safe.
- Have a Gas Safe engineer confirm the flue is clear and correctly installed.
Wiring or Control Board Problems
Loose, damaged wiring to the fan or issues with the control board can send wrong signals about fan speed.
How to Fix
- Reset the boiler to rule out a temporary glitch.
- Do not attempt internal wiring checks yourself.
- Contact a Gas Safe registered engineer for proper diagnosis and repair.
- The engineer will test connections and the board, replacing parts as necessary.
Persistent fan faults like the Worcester Bosch C6 error often lead to repeated repairs. At Eazy Heat we frequently recommend that UK homeowners and landlords consider a new boiler installation, which can save money and bring more reliable performance over time.
When should you call a professional for your Worcester Bosch Boiler C6 Error Code?
Basic external checks are fine, but fan, wiring or flue work needs a Gas Safe registered engineer. They ensure safe repairs and proper testing.
How to prevent future C6 errors on your Worcester Bosch Boiler
Keep the flue terminal clear and have annual servicing to maintain the fan and airways. Good maintenance reduces faults and supports efficiency. UK boiler statistics show serviced systems have fewer breakdowns and help manage energy costs.
Upgrade to a Reliable Boiler with Expert Installation from Eazy Heat
If your Worcester Bosch C6 error code keeps returning, it may be more than a simple fan fault. While replacing a worn fan or clearing a blocked flue can often restore normal operation, recurring C6 errors can indicate that your boiler is ageing and becoming increasingly unreliable. Frequent repairs can quickly become more expensive than investing in a modern replacement.
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FAQs
Can a blocked flue cause the C6 code in summer?
Yes, debris or nests can block it year round. Regular external checks help prevent this.
Does resetting fix the C6 error permanently?
A reset may clear it temporarily, but recurring codes need professional diagnosis.
Will insulating the flue help with C6 faults?
It can reduce condensation issues, but professional inspection is best for persistent problems.
Are older Worcester Bosch models more likely to show C6?
Yes, as fans and components wear. Upgrading often improves reliability.
What should landlords do about repeated C6 errors?
Arrange prompt repairs to maintain safety certificates and tenant comfort. A new installation may be cost effective long term.