To configure a worker process to be recycled at scheduled times
1.
 In IIS Manager, expand the local computer, expand Application Pools. 
 
2.
 Right-click the application pool you want to configure, and then click Properties. 
 
3.
 On the Recycling tab, select the Recycle worker processes at the following times check box. 
 
4.
 Click Add to add a time to the list, Remove to delete a time, or Edit to change an existing time when the worker process is recycled, and then click OK. 

  Note

When recycling is set to occur at scheduled times, it may occur off-schedule if the system time is manually altered. To avoid unintended changes in the time that recycling occurs, recycle the scheduled worker processes soon after the system time is changed.