A.O. Smith fault code C02
Fault code C02 on an A.O. Smith water heater (including BFC) means: Control error message: Incorrect reference voltage of the AD converter. 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 C02 on an A.O. Smith water heater indicates: Control error message: Incorrect reference voltage of the AD converter.
Fixing fault code C02: step by step
- Switch the appliance off at the mains for 30 seconds (unplug it), then switch it back on.
- Is it about communication with the thermostat? Then check the thermostat connection and wiring.
- Reset the appliance once. If the code comes straight back, do not keep resetting it.
- If the code comes back, the PCB or burner control unit is probably faulty. Have the appliance read out first to be sure.
Applies to
A.O. Smith BFC, 100, 120, 28, 30, 50, 60, 80.
Fault code C02 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:
- C02 on ADMR, 115, 135, 40, 50, 60: Appliance control error message. Incorrect reference voltage of the AD converter.
- C02 on Innovo, IR 12-160, IR 12-200, IR 20-160, IR 20-200, IR 24-245: Incorrect reference voltage of the AD converter/EEPROM read fault/50 Hz fault/Internal communication fault/Gas valve relay fault/Safety relay fault/Ignition relay fault/RAM fault/EEPROM fault/EEPROM content does not match the software version/Processor software fault/Ionisation circuit fault.
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. If the code keeps coming back, view the A.O. Smith parts:
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 C02 mean?
Control error message: Incorrect reference voltage of the AD converter.
How do I fix fault code C02 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 C02?
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 C02 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 →