Hi, all of a sudden, temp is too low. Cleaned everying, inside and out, grates front&back under unit. Used a second thermometer to find out it's like 10 degrees (*unit displays OR if diff. bwtn actual temp and set temp is greater than 9 degrees) Turned it off for few hours still cool below set point. Only indicator light, under unit is solid green indicating 'functioning normally' What can I try or do I need to call in the manufactor service agent?