When a dryer is taking too long to dry clothing, there are several things that you should look for. First you should find out if the dryer was getting hot on top. Then Appliance Repair Frisco Texas should find out if the lid screen was not collecting very much lint.
Also you can ask the person that uses the dryer, did it seem to be hot and humid inside the dryer all the time. If these three symptoms exist, then most likely there is a vent restriction. The very next thing that you should do is, leave the dryer running, and go outside of the building and check to see how much air is coming out of the dryer vent. If there is little or no air coming out of the vent, then you definitely have a dryer vent restriction.
The next thing you should do is turn the dryer off. You should not operate a dryer with a vent restriction for two reasons. Number one, it is not safe and there is the potential for a dryer fire. And number two, operating a dryer with a vent restriction will eventually cause the high limit thermostats, safety thermostats, or thermal cutout to fail. If one of these safety devices fail, the dryer must be repaired.
If you find when you service the dryer that you have a heater failure, or a safety thermostat, or high limit thermostat that has failed, you must check for a vent restriction after the repair is made, otherwise the heater, the high limit thermostat or the safety thermostat will simply fail again. Not to mention the fact that there is a risk of a dryer fire anytime there is a vent restriction.