We have a 2820vn on a small network. The pc's are set to use DHCP. Every 40 minutes or so when browsing the pc's cannot access internet, clicking Lan icon and clicking repair connection starts the session again. We have tried two 2820vn's both give the same problem. They are on latest software version and have been re programmed from scratch. If we plug original zyxel router in all works ok. The broadband is ADSL.

Anybody have any ideas why this should be happening

Do all the pc's have the same issue at the same time? How many machines are there? Is there a switch used aswell or just the routers built in switch. Oh and do you have any other servers / devices on site that could be giving out DHCP?