TradeAssistIQHome

Worcester Bosch Greenstar 4000 System fault 2949

No flame signal with high output

Gas boiler

What it means

May be caused by strong winds or flue gas recirculation. The burner starts automatically after purging.

Likely causes

  1. Strong winds
  2. Flue gas recirculation
  3. Incorrect CO2 settings
  4. Faulty burner/heat exchanger gaskets or inner flue gaskets
  5. Gas pressure dropping during full load
  6. Faulty ignition transformer
  7. Incorrect gas type
  8. Incorrect gas supply pressure
  9. Power supply fault
  10. Faulty electrodes/cable
  11. Faulty flue system
  12. Incorrect gas/air ratio
  13. Faulty external gas flow monitor (natural gas)
  14. Faulty burner
  15. Faulty air/gas ratio control valve
  16. Faulty gas valve
  17. Faulty seals around the burner, internal flue seals or case seals causing abnormal O2/CO2 readings
  18. Flue system integrity failure
  19. Combustion circuit fault
  20. Damaged or loose flue joints
  21. Obstructed or damaged flue terminal or terminal guard
  22. Modified flue gas system
  23. Damaged flue pipes or gaskets
  24. Leaking flue joints

Where to start

  1. Check the flue integrity
  2. Check the flue terminal position
  3. Check the CO2 settings and adjust if necessary

The full answer, free

  • 63 more checks in order
  • The readings and component tests from the manual
  • How to put it right, step by step
  • The manual page for this fault (page 76), right under the answer
Ask about 2949 freeCreate a free account

Safety: Isolate gas and power before you open the case. If you have been into the gas side, do a tightness test, and a combustion and flue check before you hand back. Gas Safe (UK) or RGI (Ireland) work only.

From the Worcester Bosch manual for the Greenstar 4000 System. Check the model on the data plate before you order parts.

Other Worcester Bosch Greenstar 4000 System fault codes