Middleby Oven Problem

I have a MM 314. Its a smaller single 360. Anyways, it started today when it falls below temp and the burner ignites the Alarm 1 light, lights up and also a noise that sounds like a like a dull gear turning starts happening. It stops as soon as it hits temp and the burner goes off. I have an oven guy coming tomorrow morning. Any one have an idea what this is?