F.035
The air/flue pipe is blocked.
Vaillant ecoTEC Plus Combi
Possible cause
Air intake pipe blocked
Measure
Check and, if required, replace the air intake pipe.
Possible cause
Gas flow pressure too low
Measure
Check the gas flow pressure and the external gas pressure switch.
Possible cause
Fault in the flue gas route caused by recirculation or flue gas blockage
Measure
Check the entire flue gas route.
Possible cause
Condensate in the combustion chamber due to a blocked condensate discharge
Measure
1. Check and, if required, clean the condensate discharge pipe including the siphon.
2. Check that the condensate discharge has been installed correctly.
3. Check the combustion chamber (electrodes, insulating mats, burner).
4. If required, replace the insulating mats in the combustion chamber.
Possible cause
Condensate pump (if fitted) defective
Measure
Check and clean the condensate pump. Replace the condensate pump, if required.
Possible cause
Insufficient combustion air supply
Measure
Check the combustion air supply.
Possible cause
Control electrode defective
Measure
Check and, if required, replace the control electrode.
Possible cause
Burner defective
Measure
Check and, if required, replace the burner.
Possible cause
Gas valve assembly defective/incorrect spare part gas valve assembly
Measure
Check and, if required, replace the gas valve assembly.