middleby ps 360s new motor tripping internal high limt

Hello all Im new to your sight but could use some good advice. We had our two top oven moters and blower fans replaced a couple months ago. it was never right and the bearings got noisey fast on the left side and we quit using it and switched to the bottom oven as its a double stack. anyhow it was covered under the 90 day warantee we payed another 500 for them to come out and tell us it was bad and would replace it but charge labor fees. so they come out and installed the new left motor in the mean time I read the service manual I am very mechanical inclined and noticed they did not put new heat slingers on both sides they left them off and when they come to fix it they were putting them on so they pulled the right side apart too. Yet only the left side ate the bearing and was noisey. Also the cooling fan on the left side was blowing outward not inward like the rest. It worked for about 2-3 hours then tripped the internal limit switch and temp went down then would come back on and then off repeatedly and is noisey again. I was able to turn the cooling fan inward so it points toward the motor. However I let it cool all day and fired it up at the end of the day to se if it helped and it didnt. My problem is the left motor repatedly trips the internal high limit switch and get very hot in minutes and shuts off without even having the burner on or the conveyor and is noisey on start up but gets quiet quickly. its only the left motor and was professionally repaired to the tune of OUTRAGEOUS. Now its down again and just comes on and off when it cools off enough. I turned the cooling fan inwards towards the motor and the upper fingers the techs lost the middle long spacer plate and made one to fit. They have no idea where it went…Any input would be AWESOME guys as I am new to the pizza business and this top oven is killing us. Is there sapose to be a spacer in the middle ? could this be causing it to not draw enough air and overload and shut down ? or could there be something else that would cause this to happen ?? its clearly overheating and tripping the internal limit switch and the tech told me the top left cooling fan was sapose to blow outwards to cycle air through the cavity when all others top and bottom blow inwards towards the motors as the manaul says and out the vent in the top and bottom of the two ovens… HELP ! lol Please as this has cost us 4K already and im not confident in our tech company. its eating up our funds fast. Thank you to any one that can help me with any insight to this issue. Also sorry if I posted in the wrong thread or forum spot. Im a newb here

Contact Middleby and report the incompetent service company. Request they advise a service agency that can resolve your problem.
George Mills

The cooling fans are for “intake”cooling air, and should be blowing into the motor area.
The big spacer (blank) is hard to lose. Most likely in the oven or on top, but they are needed for proper air movement for cooking properly. Makes me even wonder if they put the fingers back in the correct order. Usually the top of the top oven depending which side your pizza exits, goes 1 small blank, 2 number 3’s, 2 large blanks, then another number 3 followed by another small blank. Bottom of the top is usually small blank, 5 number 6’s followed by another small blank.
If you are going through main blower motors, I would be concerned if it’s the proper motor, used motors, or excessive heat getting into the cabinet from the chamber.
I also agree with George that middleby should be contacted if they are authorized agents. They may be able to help you get a resolution.

It sounds to me like the rotor is jammed. These blower motor are extremely sensitive to shock on the shaft or to the motor in general. If the installers used a hammer to beat the blower wheel onto the shaft, the motor is junk.

Try taking a decent size and weight rubber mallet and strike the motor in the center, from the exposed end, a few times. Turn it on and see if your noise goes away. Strike it a few more times if it gets better but not totally cleared. If you get no change at all, loosen the motor mount bolts a bit and strike the motor again.

I’ve had your exact problem after changing a bad motor and 3 strikes with a mallet fixed the problem.