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Heating  Heating

Brand

AO Smith AO Smith List all brands

Type:

ATI-310C-N view ATI-310C-N 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), burn marks on the computer board (Part #701), and/or soot on the flame rod (Part #108).
• Check if there is leaking from heat exchanger (Part #401).


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