Nieco JF64 Flare Ups, good morning, working an event yesterday had 1 out of 8 Nieco JF64 2G broilers experiencing excessive flare ups causing unit to spike to over 800 degrees due to flares and grease fires, this is 1 of 8 of the same models at this particular location. I completely dis-assembled and re-assembled unit, it was correct to begin with but I wanted to make certain everything was in the right place. Setting are the same on all units, product is same on all units. I dont service a ton of these units so I am leaning towards the modulating gas valve as faulty, and not properly modulating flame to control overtemps during flare ups. Unit never overtemps when running with no product, it is only when running burgers through, the one high fat item, option belt never flares with chicken or steaks, just the main belt which is used for burgers. Main line gas pressure is spot on. Any thoughts?