When a node has an issue, an event is created and this can move on to an alert being sent out.

These events will show on the wallboard and emails may continue to be sent out for this node.

If the fix cannot be done immediately, it may be desirable to use maintenance mode to suppress further events or alerts from being created.

Also, if you plan to carry out maintenance on a node you can preemptively put the node into maintenance to stop any alerts from being sent as you begin the work. 

To use maintenance mode you can simply right-click on the node and select maintenance. there are then two paths to follow, alerts only or events and alerts.

For each path, you can select a time period or use the "Until OK"  to automatically put the node back into service once the issues are cleared.

There is also a Bulk Maintenance mode option in the node manager where you can select multiple nodes/views.