Trane XL14i troubleshooting
 

My unit seems to be running constantly, yet is not able to cool to the set temp (76). I've changed filters and checked the circuit breaker and cannot think of any other obvious things to check.

Could be a lot of things
Low charge
Open return in attic
Unit to small
Ducts wrong size
Check the in going air temp at a return and the out going air at a supply vent to see what the temp. difference is.