Ideal Logic Heat fault FA
Flow/return reversed
Gas boilerWhat it means
Alternating 'F' and 'A' on display indicates the flow and return pipes are reversed.
Likely causes
- Flow and return pipework connected incorrectly / reversed
- Flue components still not properly assembled, fixed or supported after rectification attempt
- Continued obstruction of flue or flue terminal
- Seals still displaced or not properly rectified
- Flue components not assembled, fixed or supported correctly
- Flue or flue terminal obstructed
- Seals on flue extensions displaced during installation
- Combustion products and inlet air mixing due to flue defect
- Displaced seals, e.g. on flue extensions
- Combustion products leaking into inlet air path
- Incorrect gas/air ratio setting at minimum rate
- Combustion problem
- Flue gas contamination
- Faulty gas valve adjustment
Where to start
- Re-check flue assembly, fixing, support and obstructions after rectification
- Insert analyser probe into air inlet test point (where available) and allow readings to stabilise
- Allow readings to stabilise and record O2/CO2 values
The full answer, free
- 16 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 51), right under the answer
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 Ideal manual for the Logic Heat. Check the model on the data plate before you order parts.