Need to replace Pentair Dynamo (DYNII-N2-1-1/2) pump

[nanobooboo]

Good early spring! My original pump motor was built in 2/2014! Talk about a beast. All I see now are either really cheap or really expensive pumps on the market. Working with an above ground, 17K gallon pool with a sand filter. Looking for a quality replacement and a good supplier. Any suggestions?

 

[1poolman1]

Good early spring! My original pump motor was built in 2/2014! Talk about a beast. All I see now are either really cheap or really expensive pumps on the market. Working with an above ground, 17K gallon pool with a sand filter. Looking for a quality replacement and a good supplier. Any suggestions?

Waterway makes a good line of pumps. Look into their Power Defender series.

 

[nanobooboo]

Thanks! Does Waterway make pumps and sell them under different brands?

 

[1poolman1]

Thanks! Does Waterway make pumps and sell them under different brands?

Yes, they do "private label" for some companies. Don't remember what the names are.

 

[nanobooboo]

That'd be useful to know which pumps are privately labeled. Looks like a "flooded" market of cheap imported pumps. (sorry, couldn't resist)

 

[nanobooboo]

OK, Inyo Pools hooked me up with a replacement A.O. Smith motor for my Pentair Dynamo DYNII-N2-1-1/2 hp. I have the motor on the bench, sprayed a healthy dose of Liquid Wrench into the screw head which is heavily rusted. The impeller won't move a bit. Do I put a rag on the impeller end and use a big set of pliers while holding the screwdriver on the other end? I saw a video that said the impeller was reverse threaded. Any input much appreciated!

 

[1poolman1]

OK, Inyo Pools hooked me up with a replacement A.O. Smith motor for my Pentair Dynamo DYNII-N2-1-1/2 hp. I have the motor on the bench, sprayed a healthy dose of Liquid Wrench into the screw head which is heavily rusted. The impeller won't move a bit. Do I put a rag on the impeller end and use a big set of pliers while holding the screwdriver on the other end? I saw a video that said the impeller was reverse threaded. Any input much appreciated!

Plastic pumps and petroleum products are not a good mix.
Which screw head? There are no impeller screws in those pumps.
Better to get a strap wrench than pliers. Very easy to crush old plastic with large pliers.
Impellers are normal, right-hand thread (lefty loosey).
Remove the rear end bell and grab the shaft with a Vise Grip, pliers, wrench, vise, whatever works.

 

[nanobooboo]

Plastic pumps and petroleum products are not a good mix.
Which screw head? There are no impeller screws in those pumps.
Better to get a strap wrench than pliers. Very easy to crush old plastic with large pliers.
Impellers are normal, right-hand thread (lefty loosey).
Remove the rear end bell and grab the shaft with a Vise Grip, pliers, wrench, vise, whatever works.

Hi, my mistake. The impeller came right off. In looking at the diagram, the diffuser is what I can't budge...part number 354633. I have a new motor to install as soon as I can get this piece off. And yes, used a strap wrench but no joy!

 

[1poolman1]

Hi, my mistake. The impeller came right off. In looking at the diagram, the diffuser is what I can't budge...part number 354633. I have a new motor to install as soon as I can get this piece off. And yes, used a strap wrench but no joy!

The diffuser is held to the motor by the 4 long, and very thin, bolts that are in the back of the motor, it isn't threaded on. Usually either 1/4" or 5/16" nut driver/wrench is needed and don't be surprised if they break.
Those a re called "through-bolt" motors as the bolts that hold the motor together are also used to mount the wet end of the pump.

 

[nanobooboo]

I managed to get 3 of the 4 long bolts out of the motor. They were quite stretched and broke off. I'll have to go back tomorrow and get the 4th one out. Not having those long screws listed in the schematics isn't comforting. That Pentair Dynamo lasted 10 years. Question is, where to get those replacements, AND, if that diffuser will be usable after I get the broken pieces out.

 

[nanobooboo]

The diffuser is held to the motor by the 4 long, and very thin, bolts that are in the back of the motor, it isn't threaded on. Usually either 1/4" or 5/16" nut driver/wrench is needed and don't be surprised if they break.
Those a re called "through-bolt" motors as the bolts that hold the motor together are also used to mount the wet end of the pump.

1poolman1, you are quite correct! I suppose I can't be too unhappy nor was I surprised they broke. I have been to every local pool company around and nobody has any of those bolts. I called Pentair and swear I was talking to a robot. I was just looking for a part number or the specs on those bolts so I can put this thing together. I got the "since it is obsolete, we cannot provide any information..." very frustrating. SO... anybody got any ideas?

 

[1poolman1]

1poolman1, you are quite correct! I suppose I can't be too unhappy nor was I surprised they broke. I have been to every local pool company around and nobody has any of those bolts. I called Pentair and swear I was talking to a robot. I was just looking for a part number or the specs on those bolts so I can put this thing together. I got the "since it is obsolete, we cannot provide any information..." very frustrating. SO... anybody got any ideas?

New bolts come with new motor. They usually have a small nut that keeps them in place for shipping. They get removed, put in a junk drawer, looked at with the idea "I'll need these sometime," then tossed 10 years later.

 

[1poolman1]

I managed to get 3 of the 4 long bolts out of the motor. They were quite stretched and broke off. I'll have to go back tomorrow and get the 4th one out. Not having those long screws listed in the schematics isn't comforting. That Pentair Dynamo lasted 10 years. Question is, where to get those replacements, AND, if that diffuser will be usable after I get the broken pieces out. View attachment 559717

If you get the broken piece out the diffuser should be good. It will probably be OK with three, or even two if they are diagonal to each other. Be sure to put some anti-seize, or even pool lube, on the threads.