Thanks for the question. It is common within the industry for there to be a variance of up to ±25°F between the set temperature and the actual oven temperature, based on a number of factors; Samsung ranges are actually designed to have even less of a variance (±10°F to 20°F). If you determine that your FE-R300SB is running either too hot or too cool, you can adjust the thermostat yourself by up to ±35°F by following the instructions on page 28 of your user manual, which can be downloaded as a pdf file from this website.
If your range is taking 45 minutes to cook what should take only 20 minutes, it is likely that an adjustment is necessary. If you determine that your oven's temperature is varying from the set temperature by more than ±35°F, I would suggest contacting Samsung for service to make the necessary repairs or adjustments. To initiate the service process, please submit your contact information through the link below, or call 800-SAMSUNG to speak with an agent who will be happy to assist you.
Online service request form: http://www.samsung.com/us/support/o...
- Ms. Samsung