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A.O. Smith Appliances
A.O. Smith Appliances

A.O. Smith Appliance Error Codes

A. O. Smith is proud to be known as one of the world's leading providers of water heating and water treatment solutions. As a leader, they refuse to sit quietly. Each and every day at A. O. Smith, they are working on developing state of the art solutions that are pushing new boundaries and paving the way in our industry.


Water Heater Error Codes

CODE: 03 (031), One time 
PROBLEM: Incorrect dipswitch settings. 
FIX: Check for the proper settings on the computer board. 

CODE: 10 (101), Five times 
PROBLEM: Warning for the "991" error code. 
FIX: Check for blockage in the vents, the distance between the intake and exhaust terminals are per instructions and remove if there is grease or dirt in the gas burner and fan motor. 

CODE: 11 (111), Three times 
PROBLEM: The ignition failure. 
FIX: Check is the Hi-limit switch properly functioning that there is no loose or broken wire connections, no soot on the flame rod or damaged computer board. Can you hear a buzzing spark ignition from the burner or two clunk sounds from the gas valve? 

CODE: 12, 121, Three times 
PROBLEM: Flame loss. 
FIX: Check for the proper settings on the computer board. 

CODE: 31, 311, Two times 
PROBLEM: Outlet thermistor failure. 
FIX: Check is there a loose or breakage in wire connection or debris on the thermistor. 

CODE: 32, 321, Two times 
PROBLEM: Inlet thermistor failure. 
FIX: Debris on the thermistor, loose or broken wire connection. 

CODE: 331, Two times 
PROBLEM: Mixing thermistor failure. 
FIX: Debris on the thermistor, loose or broken wire connection. 

CODE: 341, Two times 
PROBLEM: Exhaust thermistor failure. 
FIX: See error code 331, 321 and 311. 

CODE: 39, 391, Two times 
PROBLEM: Problem with the air-fuel ratio rod - AFR. 
FIX: Check for the soot on the AFR rod, wire connection, and breakage. 

CODE: 441, Two times 
PROBLEM: Problem with the flow sensor. 
FIX: Check the wire connection, wire breakage and debris on the flow sensor impeller. 

CODE: 51, 55, 510, 551, Six times 
PROBLEM: Abnormal gas solenoid valve. 
FIX: Check for connection and wire breakage or computer board failure (burn marks). 

CODE: 61, 611, Four times 
PROBLEM: Fan motor fault. 
FIX: Check for connection/breakage of wires, corrosion or frozen connectors, fan motor covered with the dust, burn marks on the computer board. 

CODE: 651, Four times 
PROBLEM: Flow adjustment valve fault. 
FIX: Connections or breakage of wires of the flow adjustment valve, scale buildup on the motor drive which gets locked, water leakage. 

CODE: 661, Four times 
PROBLEM: Bypass valve fault (only model 540). 
FIX: Connections or breakage of wires of the flow adjustment valve, scale buildup on the motor drive which gets locked, water leakage. 

CODE: 70, 701, One time 
PROBLEM: Problem with the computer board. 
FIX: Check for connection and breakage of wires, burn marks on the computer board, and power supply to the unit. 

CODE: 711, One time 
PROBLEM: Gas solenoid valve drive circuit failure. 
FIX: See error codes 111 and 121. 

CODE: 72, 721, Six times 
PROBLEM: False flame detection. 
FIX: Check if the condensate drain is installed on the vent collar of the heater. Is there leaking from the heat exchanger? 

CODE: 74, 741, 751 
PROBLEM: Miscommunication between the water heater and remote controller. 
FIX: Check if the remote controller is the right type, also connections between the water heater and remote. 

CODE: 761 
PROBLEM: Miscommunication in Easy-Link System. 
FIX: Check the connections between water heaters. 

CODE: 99, 991, Five times 
PROBLEM: Improper gas combustion. 
FIX: Is the water heater set for the right elevation? Look for the blockage in the vent system and ensure if the distance between the intake and exhaust is not too small. Check if there are any foreign particles or grease on the gas burner and fan motor. Is the surrounding air contaminated?



A.O. Smith Appliance Error Codes

A.O. Smith appliance fault codes

A.O. Smith appliance diagnostic codes

A.O. Smith appliance error symbols

A.O. Smith appliance common faults


Product Reviews:

I bought a lifetime warranty water heater 19 years ago. It sprung a leak an
I bought a lifetime warranty water heater 19 years ago. It sprung a leak and A.O. Smith gave me a brand new water heater at no cost. I called A.O Smith and they gave me a return authorization number. I took that and the old water heater back to Lowe's. Lowe's gave me a store credit for a water heater comparable to the one I bought in 2000. I paid $269 back in 2000 and Lowe's gave me a store credit for $500. I added another $200 and bought an A.O. Smith heat pump water heater. They do not offer lifetime warranties anymore but hopefully my new one will last another 19 years. My new one has a 10 year warranty.
Published: September 24, 2019
Scott of New Freedom, PA
Source: consumeraffairs.com

Installed an A.O. Smith water heater about a year ago for a customer. The u
Installed an A.O. Smith water heater about a year ago for a customer. The unit failed at the dielectric fitting. After speaking to their customer service they issued a full exchange at Lowe's. I was expecting a hassle at Lowe's and it was painless. Great customer service all the way around. Thanks.
Published: January 16, 2019
Bruce of Sarasota, FL
Source: consumeraffairs.com

After 5 years of great service our water heater started acting up. The plum
After 5 years of great service our water heater started acting up. The plumber says 15 days until they can come out to fix, A. O. Smith stood behind the warranty and sent the much needed parts next day. I mean the very next day at no cost not even for shipping. I've never dealt with a warranty issue this easily. Simple install, Great company, great customer service. I look forward to many more years using their products.
Published: November 1, 2019
S. of Anza, CA
Source: consumeraffairs.com

If you look at Consumer Reports, EVERY SINGLE WATER HEATER regardless of co
If you look at Consumer Reports, EVERY SINGLE WATER HEATER regardless of company or brand is junk and easily breaks. So how you do buy a water heater? Do without a water heater? Boil water instead? Also consider many THOUSANDS of these are sold without problem, so occasionally there is a bad apple. Luck of the draw. I just got a AO Smith but I had one before that lasted for years. I just converted to gas so who knows. Yes I'm nervous... but Rheem also had its share of complaints so it's all luck of the draw. I won't be getting tankless -- the more parts and components, the more can break. I do agree you should get one with the longest warranty possible.
Published: February 25, 2018
Luke of Winter Haven, FL
Source: consumeraffairs.com

Hello. I have a A. O. Smith 50 Gal Gas Water Heater. I personally installed
Hello. I have a A. O. Smith 50 Gal Gas Water Heater. I personally installed it in 1990. The only thing that I had to do is replace the thermocouple once. It has never leaked or had any other problems. This is probably unheard of but true. 27 years and still no problems. I am going to replace it soon only because of its age. True story. I don't know if the new A.O. Smith Water Heaters are as good as the one I have, but I will buy another of the same.
Published: December 14, 2017
Dennis of Michigan City, IN
Source: consumeraffairs.com

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