Vaillant · ecoFIT pure System
F.73 boiler fault code
ecoFIT pure system
What F.73 means
Fault: Water pressure sensor not connected or has short-circuited
Safe check: Note the code shown on the display. Do not open, adjust or repeatedly reset the boiler. Contact a Gas Safe registered engineer.
Gas Safe registered engineer: The code remains or returns after the step above, or no home step applies; arrange diagnosis by a Gas Safe registered engineer.
Find a Gas Safe engineerA boiler fault code alone is not a gas or carbon-monoxide emergency. If you smell gas, a CO alarm sounds, or someone has possible carbon-monoxide symptoms, leave and call 0800 111 999 from outside.
Official source: Vaillant ecoFIT pure System Installation and maintenance instructions · Appendix D “Overview of fault codes”, F.73, printed p.47