Vaillant · ecoTEC exclusive
F.55 boiler fault code
ecoTEC exclusive combi
What F.55 means
F.55 indicates CO sensor fault. The manual warns that some shared-table codes may not be visible on every product variant.
Emergency guidance
If you smell gas, a CO alarm sounds, anyone feels unwell, or there is an unsafe flame, leave and call 0800 111 999 from outside.
Open the emergency safety guideWhen to contact an engineer
Your boiler has shut down for safety. Don't keep resetting it. Leave it off and get a Gas Safe engineer to check it.
Renting? Report it to your landlord or housing provider first. They are responsible for gas safety and boiler repairs, and the repair should not cost you.
Source and provenance
- ecoTEC exclusive combi Installation and Maintenance Instructions · 0020193968_05 · Appendix E, F.55, printed p. 57
installation and maintenance instructions
0020193968_05