I just isntalled the Forcefiled 3 subwoofer. The sub does not seem to turn off after I put my receiver on standby. Last night, I checked that even after 30 minutes, the green light on the back was still off. I had to manually plug the power cable out, since there is no on/off switch. This seems like an issue to me, I don't wanna plug the power cable in/out every time. Any ideas about what could be going on here? Should I call my dealer?

The ForceField subs will take 2-3 hours to shut down after no signal is sensed. If it does not turn off after this time you can test the cause by unplugging the input source and waiting the 2-3 hours again. If it still doesn't turn off, contact your dealer. If it DOES turn off after disconnecting the input then there is an issue with the source (receiver, presumably).

2-3 hours seems like a really long time to switch off. Does it consume a lot of power during that period?

No - less than 10 watts.

Our engineers felt the only way to insure our ForceField subs did not turn off during use was to set an extended turn off time. Based on my experience with other auto turn off subs, I believe they chose very wisely. .