Epson EMP-5500 Owner's Manual page 81

The temperature indicator is red.
The projector is overheating, which turns the lamp off
automatically. Let the projector cool for a few minutes,
then turn it back on. Make sure nothing is blocking the
ventilation vents.
The air filter may be clogged. Clean it as described in
Chapter 4 and then let the projector cool for a while.
If the projector continues to overheat after you clean the air
filter, the problem may be caused by damage to the cooling
fan or internal circuits. Contact a qualified service person.
Warning: Except as specifically explained in this User's Guide,
do not attempt to service this product yourself.
Problems with the Projector 59