Ignition failure
• 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 a buzzing spark ignition sound coming from the burner (Part #101) when water heater prepares for combustion.
• Listen for the double “clunk” sound coming from gas valve assembly (Part #102) when water heater goes into combustion.
• Check if there is leaking from heat exchanger (Part #401)
