If the unit on a work order is under warranty, a message "Unit is currently under warranty XYZ" will appear in the middle of the Edit Work Order change screen.
If a component being worked on is under warranty, the line Description on the Edit Work Order change screen will start with W*.
Depending on the setup of your system, you may be required to claim warranty before you can close the work order.
Create a claim for a specific activity
Create a claim for the entire work order
View a claim from an open work order