# Common wire



## Hastingsheatguy (11 mo ago)

I have a 9 year old lennox s280 furnace. The issue I am having is the heat will quit working without giving an error. It even does it with the thermostat jumped out. The only way I can get it to work is by removing the common wire at the control board and the thermostat. I find it odd that it has worked fine for 9 seasons and just now become an issue any thoughts would be appreciated


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## bobber (Jun 24, 2021)

Well, just off the top of my head, I'd say that wire is shorted or is breaking down somewhere. I've seen this happen a couple times and the cure that has always worked is replacing the tstat wire between it and the furnace.


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## Hastingsheatguy (11 mo ago)

I’ve replaced the wire and the same issue still happens only works if the common on the stat and control board are disconnected


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## bobber (Jun 24, 2021)

Did you replace the whole thermostat cable? You could take the thermostat and a short piece of wire and hook it up locally and see if it works with all wires in place.


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## Hastingsheatguy (11 mo ago)

bobber said:


> Did you replace the whole thermostat cable? You could take the thermostat and a short piece of wire and hook it up locally and see if it works with all wires in place.


I have also tried that and it’s still the same result


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## Hastingsheatguy (11 mo ago)

Hastingsheatguy said:


> I have also tried that and it’s still the same result


Yes the whole wire was replaced


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