Red light on mother board flashes 4 on an Armstrong Air Ultra V Tech 91 furnace.Post created: 2016-02-25 Type of Equipment: Furnace Views: 56
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On 2016-02-25 Gary wrote:
A red light flashing 4 times on this furnace indicates "Limit or Rollout Switch Open". You may need a new limit switch. It's always a good idea to have a heating contractor do this sort of repair. If you'd like to have a contractor take a look at this, we can help you find one, here.