Pentair Dynamo 1.5HP pump - bad noise - repair/replacement options?

[markcw97]

Friends, this motor/pump came with my SD40 filter 7 years ago, and I replaced the motor/pump 4 years ago after the first one was flooded (that's a long story.) It's a single speed pump and has been sounding a tiny bit noisy for the past 1-2 years, and has a very slight leak from the pump some days. Recently, my pump-to-filter hose burst and did two things -- dumped a lot of water all over everything, and drained enough water off the pool so that the pump was sucking quite a bit of air when I found it maybe 30 minutes later - that's a guess. (The bottom drain kept it from being a lot worse). After replacing the hose, I fired it up, and now it's making a really bad noise. I'm guessing that either the pump was seriously compromised by all of the air, or the motor got water in bad places (although it's exposed to rain all summer.)

Here's a video that will let you hear what it sounds like.

Although I have some repair skills, I don't consider myself great at it, and also don't have a ton of spare time these days. However, I might consider a repair if it isn't too complicated.

As far as replacing it, I've learned that this model appears to have been discontinued, and nobody has any in stock anymore. There are plenty of other brands of similar AGP filters that look like they might work, but I'm concerned about plumbing fittings and the base-mounting alignment. If there isn't some kind of "standard" setup, I'm afraid I'm going to waste a lot of time and effort trying to connect up a different pump/motor.

Anybody got any advice or ideas? Thank You so much!!!

 

[1poolman1]

One second video is hard to judge by. Discontinued standard above ground pool pump. Virtually any above-ground pump in that horsepower now available would match its performance. A new standard pump would cost less than a replacement through-bolt motor.
There are many above-ground variable-speed pumps now that would be a better replacement. They cost more initially but can save their entire cost and more in energy savings over their useful life. May need to change the inlet and outlet fittings and perhaps the whole hose.

 

[markcw97]

Thank You, and I'm sorry about the short video - I was trying to make the video smaller so it could be uploaded, and then I found out that MP4 wasn't even a supported format. Here's a slightly longer video, and I edited the link in the original post to point to this one as well.

 

[mknauss]

Upload videos to YouTube. Then post the link.

 

[markcw97]

Hopefully the link I provided works fine. Does anybody know if Pentair has released a newer motor/pump that is equivalent? Or more likely, it's a whole new pump/filter/base design that's altogether different, right?

Is there any way to determine if a new/different pump-motor would fit easily?

 

[zea3]

I've had several Dynamo pumps and they don't last but a few years. If you want the same foot print and connections then replacing just the motor will do that for you. If you want to go with a different brand then you will have to make some adjustments to the plumbing, but its not super difficult. I would also replace the base for the filter and not bother bolting down the pump if you go with another pump.

Use the model number from the motor to search for a replacement. I can't quite make it all out from the photo but if you google replacement pool pump motor with that model number you should get results that will fit.

 

[markcw97]

Thanks, Zea3. Are you pretty sure it's the motor and not the pump?

 

[zea3]

The pump has a wet end and a dry end. The dry end is the motor. Wet and dry end together are the pump. The wet end of the pump has all the connection points for the plumbing and no mechanical parts. As long as there is no damage to the wet end you can swap out the motor. There is a mechanical seal between the wet end and the dry end that keeps water out of the motor and allows the shaft to spin the impeller. If that seal goes bad you will see water leaking out of the bottom of the pump roughly in the middle of the pump. Water inside the motor will cause things to rust and corrode. Eventually the motor will seize and no longer run. A loud, whiny or grinding noise is a sign of the motor going bad. You want to make sure you do not buy a larger horse power motor than the original pump motor in order to prevent damage to the impeller. You can downsize a motor without problems.

 

[markcw97]

I did find some replacement motors, but as 1poolman1 said, the cost was right about the same as a new matched pump/motor set. I decided to go that route, with a standard Doheny 1.5 HP model. Hopefully it connects well and easily - but I remain a little skeptical!