Baxi Baxi 200/400/600/800 Combi 2 & System 2 Baxi 600/800/Assure System 2 and 600 Combi 2 platform fault E.01.12
Temperature measured by return sensor greater than flow temperature
Gas boilerWhat it means
Permanent fault requiring reset, indicating the return sensor is reading a higher temperature than the flow sensor, suggesting sensor positioning or operation issue.
Likely causes
- Sensor/connection problem
- Incorrect sensor positioning
Where to start
- Check that the sensors are positioned the correct way round
- Check that the flow sensor is in the correct position
- Check the return temperature in the boiler
The full answer, free
- 12 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 73), 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 Baxi manual for the Baxi 200/400/600/800 Combi 2 & System 2 Baxi 600/800/Assure System 2 and 600 Combi 2 platform. Check the model on the data plate before you order parts.
Other Baxi Baxi 200/400/600/800 Combi 2 & System 2 Baxi 600/800/Assure System 2 and 600 Combi 2 platform fault codes
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- AC004Failed start-up attempts after last maintenance
- DC004Number of burner start-ups for DHW mode
- DC005Number of burner start-up hours for DHW mode
- E.01.04Flame loss detected five times in 24 hours (with burner on)
- E.01.17No water circulation (permanent)
- E.01.20Maximum flue gas temperature reached
- E.04.08Maximum safe temperature value reached
- E.04.10Burner failed to ignite after 4 attempts
- E.04.11VPS gas valve test failed
- E.04.12Ignition failure for monitoring parasitic flame
- E.04.14Temperature difference between set point and burner varies more than 60s compared to...
- E.04.15Flue gas exhaust pipe blocked
- E.04.17Fault in gas valve control circuit
- E.04.23Gas valve check valve internal stoppage
- E.04.24Gas family not detected during the automatic detection function
- E.04.54Fault in gas valve control circuit
- GC007Failed start-up attempts
- H.01.05Maximum temperature difference value between flow and return reached
- H.01.08Flow temperature increase in heating mode too quick (10 minute stoppage)
- H.01.18No water circulation (temporary)
- H.01.21Flow temperature increase in domestic water mode too quick (10 minute stoppage)
- H.02.09Partial stoppage of the boiler, signal indicating blocking input active or frost...