# XE90 Gas Furnance, LED 4 blinks



## thanksagain (Nov 10, 2011)

Hi, I'm new here and don't know how to post but Ive been reading this thread,

Someone mentioned the Open High Limit Switch on a Trane XE 90, (LED blinking 4 times) I think thats whats wrong with my unit, where is it located? There are two wires going to a sensor on the fire chamber but no reset switch, might that be it, do I replace it, just unscrew it and put a new one in? If it's not resettable.


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## paul52446m (Nov 11, 2011)

thanksagain said:


> Hi, I'm new here and don't know how to post but Ive been reading this thread,
> 
> Someone mentioned the Open High Limit Switch on a Trane XE 90, (LED blinking 4 times) I think thats whats wrong with my unit, where is it located? There are two wires going to a sensor on the fire chamber but no reset switch, might that be it, do I replace it, just unscrew it and put a new one in? If it's not resettable.


You might have to take some pic. with the doors off the furnace to get help on the limit switch If there is a small switch on the burner, burner box, or inducer these are small limit switches, some times reset able. If you have a down flow furnace with the blower near the top. you would probable find a hi limit switch back in there beside the blower or even screwed to the blower and some furnace have them there that are reset able.
Paul


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## Fitmiss (Nov 12, 2011)

paul52446m said:


> You might have to take some pic. with the doors off the furnace to get help on the limit switch If there is a small switch on the burner, burner box, or inducer these are small limit switches, some times reset able. If you have a down flow furnace with the blower near the top. you would probable find a hi limit switch back in there beside the blower or even screwed to the blower and some furnace have them there that are reset able.
> Paul



The question is why is your unit reaching high limit. It doesn't necessarily mean it is the high limit switch. In my situation, my blower wasn't going on so it was triggering the high limit because the unit was working too hard.


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