Blower On Oven Getting Loud

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indie_pizza

New member
My MM oven has been getting quite noisy over the last week and I’m not really sure how to fix it. I’m sure it’s one of the blower motors, and I’m guessing it’s the bearings or something in that department. Is there a way to lube this? I’m kind of clueless in this department and wary of calling in someone to work on it. We had to replace the other motor right after buying and it came in at a tidy $1,000 after labor.
 
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Did you have the other one rebuilt as a spare? Hopefully so.

When the bearings start to go it is time to get ready. If you have a stack and can make it on the other oven you can wait for it to go. Otherwise, I would suggest lining up the replacement motor now so your down time is limited when it happens.

BTW, I saved a fair amount on the motor swap labor by taking the oven apart and cleaning it so the technian only had to actuall install the motor. That got the labor portion down to about $150.
 
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Its actually not that hard to replace those blower motors in the middleby marshall ovens. I have replaced 3 or 4 of them over the years. The hardest part is you have to take the oven completely apart and then climb in there on your back and take the blower fan/wheel off the motor shaft. There are 2 threaded holes spaced apart from the center of the shaft and if you take a standard steering wheel puller for a car and run 2 bolts through the blower wheel and turn the center bolt down on the puller the wheel will come right off, then its just a matter of 4 bolts on the motor itself and 4 wires. The motors are around $380 or so if you buy them direct and you will probably save yourself about $1000 or more if you do it yourself. When we bought our stores the ovens were already about 15-20 years old and I had to learn to work on them myself otherwise I would have went broke paying someone to repair them, I have done just about everything on them now and I can tell you they are pretty easy to work on and you will save a ton of money. You just cant be afraid to get dirty. Also if you decide to do it yourself make sure you turn the breaker off to the oven when you are working on it.

The bearing would screech on my top oven for about 45 minutes in the morning until the oven got nice and warm, it did that for about 1 1/2 years before it finally just wouldnt work anymore so if it just started making the noise you might have quite a bit of time left. If you are mechanically inclined or know someone that is it really isnt that hard of a job.
 
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Hi Indie:

You did not indicate which model oven you Have The old PS 250 and the later PS 570 and PS 555 do have lubrication points. The PS 360 does not have lubrication points.

If you have a PS 360 there are no lubrication points so it is probably the blower motor itself Or perhaps a blower wheel has lost a balancing weight. That could cause vibration.

Generally, the blower wheels on the PS 360 will be frozen on the blower shaft and the shaft will have to be severed in order to remove the motor. Then the section of the motor shaft remaining in the blower motor will have to be driven out of the blower wheel.

It is a good practice to have the blower wheel re-balanced before reinstalling it.

George Mills
 
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My PS 360’s are over 25 years and the wheel will come off the motor shaft if you remove it correctly. Like I stated in the above post the wheels have two threaded holes on either side of the center shaft, you simply run 2 1/4 threads bolts through those threads and use a steering puller or similar puller and remove the wheel. If you try and pry the wheel off or yank on the motor until the wheel comes off you will mess up the wheel and the motor. Those threads on the blower wheel are on there for that purpose. If you dont use correct tools then you are right, the wheel will not come off or will be damaged on removal, but a $10 steering wheel puller at the local auto parts store and 2 long 1/4 inch thread bolts will remove those wheels with very little effort and with no damage to either the wheel or the motor shaft. I have replaced 4 of them on my own ovens in the last 2 years on oven that were 25+ years old and I replaced 2 on our franchisee’s ovens and every single time the blower wheel came off with very little effort with the puller.

I know this from experience because one of our franchisee’s tried prying the wheel off and yanking on the motor and thought it was seized up, they ended up mushrooming the shaft inside the wheel because they decided to use a air hammer to try and get it off. He was amazed when he saw how easy the other wheel came off with the puller.
 
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MR Epizza24 has described the proper way to remove a PS 360 Blower wheel.

Obviously I should have included that in my message.

We had a rebuild shop years ago and rebuilt hundreds of MM PS 360 ovens. We had factory trained technicians on staff that always tried using a puller as indicated. As often as not the shaft was so frozen in the blower wheel that the motor shaft had to be cut in order to remove. I hope Indie can, if necessary, get his off with a puller.

George Mills
 
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Thanks for the info guys, I’m using a ps250. Can’t seem to find the lubrication points on any of my literature. I’m going to dig around tonight after we close and see what I can come up with. The potential work and cost of replacing the motor is not a pleasant thought.

bodegahwy - I wish I had been smart enough at the time we replaced the last one, but it was within a couple weeks of purchase and they saw my greeness a mile away and really gave me the shaft, never going to call them again…even if the owner is a city commissioner.
 
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Hi Indie:

RE MM PS 250 ovens

There are bearings on the shafts that drive the blower wheels. Those bearings normally have grease fittings on them. Failure to lubricate those bearings can result in noise and eventually failure of the bearing.

George Mills
 
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epizza24
It might be a pain, but I bet it would help a lot of operators if you took pictures, or even video, the next time you had to do that.

Can you imagine if we all started a bank of operator self repair videos on ovens and refrigeration? You’d almost think a parts supply company would do that for us! Even easy stuff like changing a faucet would save some operators hundreds of dollars!
 
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You know thats not a bad idea. I actually have to replace a motor on my oven at my other location, it needs bearings badly but I probably wont change it until after the new year because once the oven warms up the bearings settle down, its been doing that for about a year so I don’t think a few more months are going to kill it. When I change that motor I will be sure to take plenty of pictures and post them up and take pictures of the tools etc…

Unless you are rich you almost have to work on equipment if you are a independent operator. I have saved myself thousands and thousands of dollars over the last 10 years. Its a little easier for me to work on mechanical things because I was a ASE Certified Auto Tech before I bought my first store but if you have any mechanical ability at all its well worth your time to get to know your equipment. I really never messed with ovens to much but the last 2-3 years they have broken down so much I was almost forced to learn them, and now I am very comfortable working on them, just got to remember to cut the power and gas to them depending on what you are taking apart. I am by no means a expert but I know enough to be able to fix almost everything on them. My ovens are 25+ years old and the one in my main location I think I have just about rebuilt completely in the last 2 years, anything that could break or go wrong has. If I would have paid someone I would have probably spent about 10k on just that oven alone easy.

I will definitely take some pics on the next blower motor install, probably sometime in Jan.
 
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