TradeAssistIQHome

Worcester Bosch Greenstar 4000 System fault 2950

No flame signal following starting procedure

Gas boiler

What it means

No flame signal detected following starting procedure. Burner restarts automatically after purging.

Likely causes

  1. Low gas pressure at full load
  2. Incorrect CO2 settings
  3. Faulty burner/heat exchanger gaskets
  4. Faulty ignition transformer
  5. Incorrect gas type
  6. Incorrect gas supply pressure
  7. Power supply fault
  8. Faulty electrodes/cable
  9. Faulty flue system
  10. Incorrect gas/air ratio
  11. Faulty external gas flow monitor (natural gas)
  12. Faulty air/gas ratio control valve
  13. Faulty non-return valve in burner hood assembly
  14. Faulty seals around the burner, internal flue seals or case seals causing abnormal O2/CO2 readings
  15. Flue system integrity failure
  16. Combustion circuit fault
  17. Use or storage of cleaners containing chlorine or hydrogen halide (spray cans, primers, cleaners, paint, glue) near appliance
  18. Build-up of dust

Where to start

  1. Check gas pressure whilst burning at full load
  2. Check CO2 settings, adjust if necessary
  3. Check burner and heat exchanger gaskets

The full answer, free

  • 41 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 2950 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