Examined Convection Oven unit, found off, turned on, set to 350, let unit fully heat and cycle actually temp 364, let heat and cycle unit back on 332 off 354 and consistent with temperature - turned oven thermostat on off 15-20 times, oven went into main flame every time. Set oven to 400 cycled off 397, cycled back on 377 0ff 395 - could not duplicate customer problem while testing and Tony from maintenance was on site with Tech and looking at temp meter if oven acting up could not determine any problem while on site.