We have encountered some unwanted and disturbing noise on our ZoneDirector, the noise lasted for around 2 hours but stopped on itself. Please see my shared link of the video taken during the incident: https://drive.google.com/open?id=0B2EPe3bdUiyAa054aUl6Mmt2SFU
Could anyone please tell me what's wrong with our unit? What can we do to prevent this to happen again..