A dryer that only starts at certain times can be caused by a few different factors, some of which include:

1. Timer issue: If the dryer only starts at certain times, the timer may be the problem. The timer controls the cycle length and could be defective or misaligned.

2. Thermal fuse issue: The thermal fuse is a safety device that cuts off power to the dryer if it overheats. If the thermal fuse is tripping, the dryer will only start again when it has cooled down.

3. Thermostat issue: The thermostat regulates the temperature inside the dryer and can cause it to only start at certain times if it is defective.

4. Start switch issue: The start switch is responsible for turning the dryer on and off. If the switch is damaged or not working properly, the dryer may only start at certain times.

It would be best to troubleshoot these issues one by one to determine the root cause of the problem and to ensure that it is repaired properly.

Please call Appliance Force to probably diagnose and repair your issue.