A.O. Smith fault code X57-XXXX
Fault code X57-XXXX on an A.O. Smith water heater (including Twister) means: (Lockout) Short circuit of the flame sensor: Electrical connection between the flame sensor and the tank or burner. Reset the appliance once. If the code comes back, a part is usually faulty, often a temperature sensor. 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 X57-XXXX on an A.O. Smith water heater indicates: (Lockout) Short circuit of the flame sensor: Electrical connection between the flame sensor and the tank or burner.
Fixing fault code X57-XXXX: step by step
- Reset the appliance once; a one-off measuring error will then clear.
- Where you can reach it without opening the sealed combustion section, check that the sensor plug is seated firmly and the wiring is undamaged.
- If the code comes back, the sensor or its wiring is usually faulty (short or open circuit). Sensors in the sealed combustion section should be replaced by a qualified heating engineer.
Applies to
A.O. Smith Twister, TWI 35-200, TWI 45-200.
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.
For fault code X57-XXXX, the part involved is usually in the category: burner.
Based on the cause, these original A.O. Smith parts fit (always check the type number of your appliance):
- A.O. Smith thermostat sensor € 159.01
- A.O. Smith sensor 0313301(S) € 179.40
- A.O. Smith sensor kit eco Honeywell 0313306(S) € 198.42
Further reading on this cause
Other A.O. Smith codes with the same cause
- 045 — Damaged wiring and/or defective sensor.
- 047 — Short circuit in the sensor circuit.
- 502 — Sensor fault: Sensor is not (correctly) connected.
- 503 — Sensor fault: Sensor is not (correctly) connected.
- 504 — Sensor fault: Damaged wiring and/or defective sensor.
- 512 — Sensor fault: Short circuit in the sensor circuit.
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 X57-XXXX mean?
(Lockout) Short circuit of the flame sensor: Electrical connection between the flame sensor and the tank or burner.
How do I fix fault code X57-XXXX 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 X57-XXXX?
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 X57-XXXX 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 →