A.O. Smith fault code F05
Fault code F05 on an A.O. Smith water heater (including Innovo) means: Flame fault: Recirculating flue gases caused by an incorrect roof or wall terminal. Reset the appliance once. If the code comes back, a part is usually faulty. You can check the water pressure and settings yourself; leave work on gas-carrying parts to a certified gas engineer.
After a safety alert (gas, flue gas, combustion), reset no more than once and call in a certified gas engineer. If you smell gas, call your national gas emergency number or 112 immediately.
Cause
Fault code F05 on an A.O. Smith water heater indicates: Flame fault: Recirculating flue gases caused by an incorrect roof or wall terminal.
Fixing fault code F05: step by step
- Check that the gas valve at the appliance is open and that other gas appliances, such as the hob, are getting gas.
- Check that the condensate trap under the appliance is filled and clean; a blocked condensate drain can make the boiler lock out.
- Check outside that the air intake and flue are clear (leaves, a nest, ice or snow).
- Reset the appliance once. If the code comes straight back, do not keep resetting it.
- If the fault keeps returning, the ignition or ionisation electrode is usually worn or dirty. It sits in the sealed combustion section: have it replaced by a qualified heating engineer.
Applies to
A.O. Smith Innovo, IR 12-160, IR 12-200, IR 20-160, IR 20-200, IR 24-245, IR 24-285, IR 32-245, IR 32-285.
Fault code F05 on other A.O. Smith series
The same code does not mean the same thing on every series. Check the rating plate to see which series you have:
- F05 on Innovo, IR 12-160, IR 12-200, IR 20-160, IR 20-200, IR 24-245: Flame fault: Gas supply insufficient.
- F05 on Innovo, IR 12-160, IR 12-200, IR 20-160, IR 20-200, IR 24-245: Flame fault: Supply voltage too low.
- F05 on ADMR, 115, 135, 40, 50, 60: Too many flame faults detected. Incorrect roof terminal, recirculation of flue gases.
- F05 on BFC, 100, 120, 28, 30, 50: Too many flame faults detected: Incorrect roof or wall terminal / Recirculation of flue gases.
Matching parts
A.O. Smith parts are available from Instalpunt; shipping to EU countries from €12.95 (€16.95 for more distant countries), usually 3–5 working days.
This message does not point directly to one faulty part. These are the parts that most often fit this appliance:
- A.O. Smith ionisation pin after September 2009 € 43.49
- A.O. Smith glow plug for e.g. Innovo IR32-380L 0311990(S) € 96.49
- A.O. Smith fan adapter € 101.93
Fix it yourself or call an engineer?
Always consult the manual for your appliance and work safely. If in doubt or if the fault comes back, call in a qualified professional. A question about a part? Write to us at info@instalpunt.nl.
Frequently asked questions
What does A.O. Smith water heater fault code F05 mean?
Flame fault: Recirculating flue gases caused by an incorrect roof or wall terminal.
How do I fix fault code F05 on an A.O. Smith water heater?
First check the cause described above. Then restart the appliance using the reset button. If the message comes back, a part usually needs replacing or the fault needs to be repaired by a qualified professional.
Which parts do I need for A.O. Smith fault code F05?
That depends on the exact cause. In the A.O. Smith parts overview at Instalpunt you will find the current price and stock for each part.
Can I fix fault code F05 myself?
You can reset the appliance and check things like the water pressure or settings yourself. Work on gas-carrying parts must be left to a certified gas engineer.
All A.O. Smith water heater faults and codes at a glance →