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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:

121
List all errors


Error code: 121

Cause of error code 121

Loss of flame

Solution for error code 121

• Check if the Hi-limit switch (Part #412) is properly functioning.
• Check for connection/breakage of wires (Part #413, 708, 709, 710, 712), burn marks on the computer board (Part #701), and/or soot on the flame rod (Part #108).
• Check ifthere isleaking fromheat exchanger(Part #401)


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