I am curious as to what interval you have set to ping your phone. I have mine set for every 5 minutes during the day at home, every 20 minutes at night at home and every 10 minutes when away.
What do you think is best?
http://forum.micasaverde.com/index.php/topic,1997.540.html
The key here is to set it up your phone to do something on your network at least once every timeout period. See above link if you need some more hints.