cma impeller removel

[ectofix]

I saw your other post.  Glad you figured it out. I’ve been there & done that, but lucky enough to have never broken the blade on my big screwdriver.  It’d be nice if they put a hex on that shaft end in order to accept a standard socket wrench.

 

Although this is too late to help you at 8pm last night, but it may help others in the future.  But, here I go…

 

Some dishmachine pumps use a key-way and a nut to retain the impeller.  Jackson dishmachines come to mind in such a case.  Otherwise, as you discovered, CMA uses a threaded impeller that screws onto the motor shaft.  Encountering those always leaves us wondering which direction it unscrews to remove it.

 

Obviously the direction of rotation determines how it’s going to be threaded (CW or CCW).  If a motor happens to run the wrong way (like on a 3Ø motor that’s wired incorrectly), the impeller would unscrew itself from the motor shaft.

 

Here’s a short video that explains how to determine the direction the motor rotation by looking at the impeller vanes.  As he describes, the vane section nearest the center will point in the direction of rotation:

 

 

 

 

Here’s an illustration of a pump.  You can easily tell the direction of rotation by which side is the discharge from the casing -or the “volute” as it’s called.  Again, by looking at that, the direction of rotation can be determined:

 

Here’s a TSB on the subject that CMA published some years ago.  They show some nifty tools here that I’m SURE you’ll rush right out to purchase

 

So, by watching that video and seeing this illustration, then thinking about it, you’d realize that removing the impeller requires unscrewing it from the shaft in the same direction that the motor runs.  Obviously by attempting to turn the impeller in the direction OPPOSITE of motor rotation, you’d be further tightening the impeller onto the motor shaft.

 

Here’s a TSB on the subject that CMA published some years ago.  They show some nifty tools here that I’m SURE you’ll rush right out to purchase :

 

http://www.cmadishmachines.com/sites/default/files/service_bulletins/114–SERVICE%20BULLETIN_Motor%20Impeller%20Removal_4-1-08.pdf