worcester boiler stops working, every couple of weeks. not lock out?

Hi
Can anybody help? I have a worcester oil wall monted boiler 3yrs old. Its a Danesmoor wm 12/19. It cuts out now and then and the only way it will restart is by removing front cover and pressing left side button underneath the boiler. Its not the lock out reset button. These are tiny push switches that stay up when pressed, is it some sort of reset for a thermostat?. Can any body help. Is it a diy fix or should i call a pro? Thanks
pridie30@aol.com

Thanks
edd