To troubleshoot a dryer, you must first identify the specific problem. Common problems with dryers include not starting, not heating properly and making unusual noises.
If a dryer refuses to start, check to be sure the door latch is engaging properly. Clean any lint or debris that may be trapped in the locking mechanism. A dryer may also fail to start due to incoming power problems. Unplug the dryer and plug another device into the socket. If another device works when plugged in, check the outlet with a volt meter to be sure it is transferring the correct voltage to the dryer.
If a dryer does not heat properly, disconnect the dryer from all power sources. Use a multimeter to check the continuity of the voltage current to the high limit and cycling thermostats. If there is no problem with the thermostats, use the multimeter to check voltage continuity to the coils. For gas dryers, use the multimeter to check voltage continuity to the ignitor and radiant flame sensor. Parts on a dryer that are not receiving continuous voltage must be replaced in order for the dryer to operate properly.
Unusual noises from a dryer can be caused by problems such as poor leveling, small objects caught in the dryer drum or a damaged dryer belt. Check to be sure the dryer is level on all sides. Inspect the dryer drum and remove any objects such as coins. Replace belts that are frayed or damaged, such as the driver belt.