The Mercury arc lamp will not start when warm. Before the lamp can be turned back on, the arc tube must have a chance to cool down or the lamp will not restart for a period of time called the restrike time. The restrike time is 2-20 minutes.
The time required to reach full brightness is 1-15 minutes.
(We suggest that the lamp be turned on 10 minutes before taking measurements and not turned off until the lab is complete.)
If the lamp will not turn on after cooling 25 minutes, then the lamp should be replaced. The lamp has a 1-year manufacturer warranty. Please contact Teacher Support with the serial number of the lamp and your contact information.