F0Ideal
Ideal F0: no water flow thermistor
Checked against Ideal's own documentation: Ideal Heating: what does my boiler fault code mean?. Last reviewed October 2026. How we check
Check these first, then call an engineer
Ideal's general fault code guide describes F0 as: no water flow thermistor.
What you can safely do
- Reset the boiler once, as Ideal advises.
Call a Gas Safe engineer if
- F0 comes back. Ideal says an engineer visit will be needed: quote the code when you call.
Find a Gas Safe engineer near you
Opens the official Gas Safe Register search.
Applies to Ideal boilers (Ideal's general fault code guide). Codes can differ between models, so check your manual.