U6
Worcester Bosch
Flame Detection / Gas Valve Control Fault
Boiler shows U6, often related to flame detection or gas valve control.
Advertisements
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Advertisements
Possible Causes
Faulty gas valve, Faulty flame sensor, PCB output fault to gas valve, Incorrect earthing or polarity
How to Fix / Troubleshooting
Safety first: Turn off power and gas supply if you suspect a gas fault. Do not attempt to adjust the gas valve.
- Check other gas appliances: Confirm they operate normally.
- Reset once: Try a single reset. If U6 returns, stop resetting.
- Engineer tasks: A Gas Safe engineer should test gas valve operation, check flame sensor signal, verify correct earthing and polarity, and replace the gas valve or PCB as required.
Advertisements
Repair Difficulty
Professional Required
5/5
Advertisements