I'm working on a frymaster deep fryer at a mcdonald's. I have been having intermittent hot hi and probe failure problems. I watch the temperature show very erratic readings intermittenly then work normally most of the time. I already replaced the interface board, wiring harnesses, front panel (board), temperature probe, ingitor cables. Tech support thinks it's an interference problem with the ignitor cables, but it happens when not calling for heat. I actually have this problem on split vats at 2 mcdonald's. I'm geussing it may be a heat issue so I tried putting a small cooling fan toward the control box but it didn't seem to work. Any help would be appreciated.