Pizza oven is killing me

So I/we/no one can figure this thing out. It's been an ongoing issue and needs resolved so I can stop thinking about it 24/7 and get some sleep.

Here's the scoop...

It's a Doyon model PIZ6. This is a 208 volt 3 phase oven. There's nothing fancy about this thing, which makes this all the more frustrating.

The issue is the blower motor reversing contactors are dropping a leg and single phasing the motors. This blows the motor fuses and trips the panel breaker. Getting to this point (figuring out the contactors were dropping a leg) took weeks. In the meantime we confirmed and reconfirmed the breaker panel and supply wiring is sized correctly. We replaced everything associated with the motor circuit, some things more than once, and re-wired the entire motor circuit. We have only used OEM parts. And speaking of the manufacturer, they haven't been any help except to say the oven should be replaced. 

The contactors have been replaced something like ten times. They last a week or so and poof. They are 25 amp Siemens I believe. The motor draws 1.9-2.1 amps while running and the inrush current is 12.6. The contactors are plenty big. In fact, we even put in 50 amp breakers to see if that would solve the problem but it didn't. So what the heck is causing these contactors to fail? What am I missing?

More: kích thước máy hút mùi nhà bếp, cách lắp đặt máy hút mùi

Edited September 11, 20179 yr by blackmint