Newly installed OTR microwave (ME19R7041FG). I've cooked with it once and it cooked fine but I didn’t hear a fan running, just a constant hum, and it was full of steam when I opened the door. Is this normal? I've never used a microwave where I couldn't hear a fan. It doesn't seem right but, like I said, it's brand new and I didn’t know if this was a Samsung thing.