Replacement pool pump for older Sta-rite Dyna glas/Dyna-Max

I currently have an older Sta-rite Dyna-Glas (or Dyna-Max). I am not sure since both come up when I type in the model number (MPRA6D-146L). It has a 1.5 HP Century AC motor (B371, part 7-186642-01, Frame Y48Y). I have two questions that i hope this forum can help me out with

  1. What is a current model VSP that i can easily drop in a replacement without needing to do any re-plumbing?

  2. I don’t know how old the pump is as it came with the house but does you guys think i should replace the entire pump or just the motor.


Well, I think I have a long answer to your short question.

We (almost) always recommend just replacing the motor rather than the entire pump. The pump parts are readily available and you won’t have to touch the plumbing if you just replace the motor. And pool pumps last a very long time in a well-maintained pool.

Your pump came from the factory with a 3/4HP Uprated motor (.95 total HP) but it currently has a 2.25 total HP motor on it (Read our article on Are All Motors Created Equal? to get the real story on the total horsepower of a motor).

If the impeller and diffuser were replaced to match the motor then you would need this V-Green EVO 2.25 HP Up Rate VS Motor, Square Flange 48Y Frame, Variable Speed - Model EVQ225 but we often see that local pool stores don’t stock every possible motor for every possible pump, so they just give you a higher horsepower motor and send you on your way. This can cause your pump to use more electricity than it needs to and raises your utility bill without giving you any more pumping power. If your impeller and diffuser are rated for the higher horsepower motor then go with the EVQ225.

If the impeller is the same one as it came with from the factory then the V-Green EVO 1.30 HP Up Rate VS Motor, Square Flange 48Y Frame, Variable Speed - Model EVQ130 will be a perfect replacement. I know, this is a little higher horsepower as well, but it actually doesn’t make a difference in the variable-speed motors.

If you just want to get a variable-speed motor and don’t want to pull your pump apart to see what impeller it has, get the Sta-Rite Dyna-Glas and Dyna-Max Pump VS Motor Upgrade Kit - 2.2HP - MKIT47VS22. It has a new motor as well as a new impeller, diffuser, and all of the seals you will need. If the flow is too much at full speed just turn it down. You will save a LOT on your utility bill!

Fun fact: Variable-speed motors are actually variable horsepower motors so you can put a higher HP motor on an impeller designed for lower HP and still reap all of the benefits of a lower electric bill.

Whatever you do, be sure to get a tune-up kit for it for a leak-free installation.

Thank you so much for the advice. I want to include why I am servicing the pump. I am hearing a very loud high pitched sound. it is unbearable to be even outside with it on. the beginning of last season it was making a small high pitched sound that isn’t too bad and its the same sound its always made since moving in. I read online that this could be related to the bearings. I am not looking to rebuild that and also want to upgrade. pardon my ignorance but the bearings are in the motor and thus replacing the motor should fix this issue, right? Also, how do i check to see if the impeller was properly sized?

You are correct - that high-pitched squeal is most likely the motor bearings going bad, so replacing the bearings or replacing the motor will fix that (and make your neighbors breathe a sigh of relief).

The only way to see what size impeller is in the pump is to open it up and remove the diffuser. There should be a part number molded into it - be sure to write down everything you see (and take a picture) and we would be happy to let you know what it is. It is possible that the original pool owner or pool construction company wanted to (or needed to) get more flow and upgraded the impeller and motor but I would want to be sure.

Thanks again for the fast reply. I have rebates when upgrading to a variable speed pump which end up making purchasing a new pump cheaper. Before I go down the motor route, is there a recommended pump that I can drop in with minimal pipe fitting?

Your best drop-in replacement would be a Speck EasyFit DYN pump with a variable-speed motor of 1.5HP or better (there should be a 1.65HP model available but, unfortunately, we do not currently carry them).

You may also get a rebate by purchasing a variable-speed motor which will be less expensive than a new pump. Double-check on that - your wallet will thank you!