Where is the high limit switch on a Trane XE90?

Trane XE90 High limit switch problems?

• I am getting 4 blinks on the led light and the furnace is running but blowing cold air. The code says it's a high limit switch problem and I have looked around the net and it seems this unit has 3 switches can anyone tell me where these are located? And how to tell which one may be bad? Thanks

• Answer:

  Limit switches look like a disc the size of a quarter or 50 cent piece, but thicker and have terminals for the wires. depending on your furnace they may be stacked. these are called the sequencers. They open and close the circuit depending on what the furnace/thermostat calls for Most systems are complictated and shouldn't be messed with unless your qualified to do so.you can do more harm than good.Your best bet, call a heating /cooling contractor. should be under $200 to fix by honest contractors