Diagnosis
The thermal overload protector is kicking in because the pump is getting too hot. The number one cause is using it with the '0°' red turbo nozzle for extended periods without trigger breaks.
How to Fix It
This pump is designed for intermittent use. If you're doing a long job, you must use a wider-angle tip (like 25° or 40°) and/or adopt a 'spray, pause, spray' rhythm. Don't hold the trigger down continuously for more than 2-3 minutes at a time. Let it rest for 30 seconds to cool.
If That Didn't Work
Overheating can also be caused by insufficient water supply (check for kinked inlet hose) or using water that's too hot. specifies inlet water should not exceed 104°F. Very hot water from a sun-heated hose can contribute.
Heads Up
Let the unit cool down completely (red light off) before restarting. Forcing it back on while hot can damage the pump motor windings.