29eca9e9_FAQs___3M_ESPE_South_Africa__Solution
[Problem] During light emission in continuous mode, an error signal sounds for 2 seconds, the emission is stopped, and the handpiece switches to sleep mode. [Possible Cause] The information in the Instructions For Use about intermittent operation has not been observed. (See under the header “Technical Data – Handpiece.”) The handpiece has become overheated in the course of use. The handpiece can be used again once it has cooled down. [Solution] 
Allow the handpiece to cool for 3 minutes, then start the next exposure by pressing the START button.
FAQs - 3M ESPE South Africa
Solution