Compare your dryer airflow to another one, may still be an airflow problem. I use a cheap manometer to check airflow. Also, might want to check heater power with an amprobe. Might want to verify holes in the top of the heater housing are clear.
Last thing to do, remove the overload thermostat, should be a 245 degree stamped on it. Put it in the oven and verify it opens at 240 degrees.
Did the clothes came out of the washer relatively dry?
How large and heavy to dry was the load?
Which cycle and temperature settings did you use?
Is there any difference between the dryer wall outlets (3 or 4 wires) in your friends house and now?
What is the condition of the lint screen? If it’s rusted and partially blocked, then it can cause restricted air flow.
BTW, where is the dryer located and what is the ambient temperature?
Gene.
P.S. There is the air flow test kit designed by Whirlpool to check if your dryer is getting enough air. It comes with the complete instructions. You can order it from APP for just $4.22 ans return it later.
- The air test kit AP3121973