I just got a 32qt rack from a show. This is my first rack and it has 3 inch heat tape in the back. I have a herpstat 1 hooked up to it and that is working fine. The probe is placed on the tape in the correct way (Builder did it himself and other breeder that uses the rack confirmed it) and the tape has been on for about 4 hours. With a temp gun, the tape reads 90 degrees but the rack is not warm. The tape doesn't even feel warm at all. Is this normal? I'm confused..