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Heating  Heating

Brand

AO Smith AO Smith List all brands

Type:

ATI-340H-N Outdoor (T-H3S-OS) view ATI-340H-N Outdoor (T-H3S-OS) List all types

Error code:

721
List all errors


Error code: 721

Cause of error code 721

False flame detection

Solution for error code 721

• For indoor models, check if condensate drain is installed on the vent collar of the water heater.
• Check ifthere isleaking fromheat exchanger(Part #401)


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