Epson 821p - Manual (Page 79)

Solving Problems 79
What To Do When the Lights Flash
The lights on top of the projector indicate the projector’s status and
let you know when a problem occurs.
If the projector is not working correctly, first turn it off and unplug it.
Then plug the power cord back in and turn on the projector. If this
does not solve the problem, check the status lights on top of the
projector and try the solutions recommended in the following table.
Lamp light
Power light
Temperature light