I just bought a used Roper dryer from a discount store. They said they had tested it to make sure it works and it does. But my problem is that it takes multiple times to dry one load of laundry. I have looked it up on other websites and there is not a single clear answer, I have checked the vent, disconnected it from the vent and ran it connected and disconnected and it is still the same. Is there anything I can do? Is there something that I can replace or clean out?
Here are your parts
Replacement parts for WHIRLPOOL REX3615EW0 | AppliancePartsPros.com
Here is the wiring diagram
https://www.servicematters.com/docs/wiring/Wiring%20Sheet%20-%203401728.pdf
Here is a wiring diagram from another unit (LER4634) looks the same as the above but a better quality
https://www.servicematters.com/docs/wiring/Wiring%20Sheet%20-%203406688.pdf
[COLOR=Blue]Is there something that I can replace or clean out?[/COLOR]
You have do do some diagnostics.
You need heat and air flow to get decent drying.
Remove the unit from the vent so you can feel the exhaust air.
Undo the dryer from the exhaust
If you do not want lint in the house.
Take a pair of pantyhose, put one leg into the other and attach this to the dryer exhaust.
Leave enough room behind the dryer so it can blow out like a windsock.
Start it up.
Do you have good air flow?
Does changing the temp selector change the temp of the exhaust air?
Is the exhaust temp hot on a high temp setting?
Running on air only is the heater still coming on?
Does the timer advance in both timed dry and auto cycle types?
Here is a good site with basic dryer repair help
http://www.applianceaid.com/dryers.html
Note your Roper is probably a Whirlpool.