By default Pulse will disconnect users after 1200 seconds of inactivity. To update the timeout setting, you can open the confPulse.cfg file you will find the SessionTimeout parameter:

[WebServer]
Port = 8098
UseSSL = False
SSL = false
WebTheme = kendo.blue
RefreshInterval = 1
SessionTimeout = 1200

Once updated, save the file and restart the Pulse Application Server.