Upon arrival homeowner informed me that light switch was not working, went to light switch and turned fireplace on multiple times. Checked pilot throw and it was completely engulfing thermocouple and thermopile, tested millivolts on thermopile when OFF at 387 and ON at 189. Took fireplace apart and polished both flame sensors and retested millivolts on thermopile and when flames were ON it was at 267 and OFF it was at 499 which is range. FIREPLACE MAINTENANCE 1st visit • cleaned the unit from dirt, dust, and debris • inspected the glass • inspected the rope seal on the window • inspected the flue and or combustion chamber • inspected the flu cap assembly • inspected the fan assembly • checked the fans alignment and bearings • inspected the burner assembly for deterioration • cleaned the orifice • cleaned the pilot assembly from carbon build up • cleared the pilot orifice • polished the thermopile • polished the thermocouple • polished the ignitor rod â€