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5 Flashing Light on United Technologies electronic furnace controls series 1018

Does anyone have any idea what 5 flashing lights mean on the series 1018 UT furnace controller. The manual that I have list 1 to 4 flashing lights, but not 5 flashing lights. I thought maybe the control was bad, so I swapped it out and got the same thing with the other controller. I figure it has something to do with flame sensing signal. Does anyone know what this error is referencing.


  • Tim McElwain
    Tim McElwain Member Posts: 4,506
    edited November 2017
    Some controls will give that signal when the igniter (Hot Surface Igniter) is not giving off sufficient microamps. Try changing the igniter. Also make sure you have a good ground and that polarity is correct.
  • Patrick_Henry
    Patrick_Henry Member Posts: 2
    It turned out the gas valve was the problem. It keep dropping out. I guess the 5 flashing lights indicates flame loss after ignition or unsustainable flame after several successful ignitions. The controller is sensing the flame is there, but then looses the flame signal and tries to restart the burn. After the 3rd try of a continuous burn and flame out, it displays the 5 flashing lights.