Booster Pump Reducing Valve?

Jelly roll

Aug 22, 2017
New Waverly, TX
So, I have an LA01N booster pump that is powered by a Century B668 motor. Both are not older than 3-4 years old (inherited this pool this past summer).
I knew the pump was needing to be rebuilt so I bought the replacement parts for a DIY rebuild. Then right before I started this project, the motor bearings went out. So, I bought the replacement bearings. Once I took the motor apart, I realized I needed a new motor (completely saving this guy).
Bought a new B668 motor and installed the pump and plumbed it up. Everything was swapped out with exactly the identical equipment. No upgrades and no issues on the build back.
However, when I start the pump/motor, I get a slight electrical burning smell, but nothing is overheating to the point of shutting off. After noticing this smell, I have only run the pump while I'm there watching it and maybe for 15 minutes and maybe a total of 4-5 times.
I thought maybe the windings needed to burn off that "new motor" coating? JK. But I did think maybe there was something that was needing to be burned off while it operated for the first time.
I called Century and they said to no burning smell should come from the motor, but to check the amps. So, checked the amps and it's pulling 7.5 but is rated to pull 6.5. Called Century back and they said that the impeller is under load and I should install a reducing valve on the outflow side to help reduce this.
Has anyone ever installed a valve to reduce the outflow of their booster pump?
Could the impeller be bad?
Any other ideas?
I attached a picture of my pool equipment setup.



TFP Expert
LifeTime Supporter
Jan 4, 2016
Sydney, NSW, Australia
Nice to meet you via TFP. I have no direct experience with that pump, but it sounds like the ideal fix would be a lower rated impeller. Try phoning inyopools or sunplay and asking about the availability or their recommendation regarding a lower rated impeller.

A throttling valve to restrict flow should get it done. It's just a ball valve on the outlet side, partially closed to the point where you get the correct amperage, if that's going to happen. It would be low cost to try it out.

Sounds like it's been a bit of a headache!

Jelly roll

Aug 22, 2017
New Waverly, TX
Thanks for the reply.
I've tried the different impeller route, and INYO Pools is exactly who i called. They could not find a different impeller. There is an impeller for an older pump, but back from 96....mine isn't that old. I'm also in discussions with Pentair hoping they can tell me more about the impeller, but I've gotten stonewalled by them.
I think I might go the ball valve route first.

It's just weird that all of the identical equipment was reinstalled and now I'm having an issue. Or, it might have been an issue before and I just didn't realize it. The pump and motor didn't last but 2-3 years.


TFP Expert
Mar 2, 2011
The pump does need a certain amount of resistance to operate properly. If the cleaner is attached, the resistance should be correct. There are reducer discs that can be added to the wall fitting to provide correct pressure.

See the red and blue disc here:

Zodiac UWF Connector Assembly (9-100-9001) -

I suspect that you probably have other issues than pressure.

Check that the voltage is correct when the pump is on.


Gold Supporter
May 16, 2010
Chapel Hill, NC
"Called Century back and they said that the impeller is under load and I should install a reducing valve on the outflow side to help reduce this."

Typically, if this is the case, the pump would be making a lot of noise.

Jelly roll

Aug 22, 2017
New Waverly, TX
Good to know. But mine is running smooth and quiet.......thank goodness.

And I’ll add another repair to the project as my fittings are now slightly leaking around the outflow fitting on the volute. I loaded them with tape and silicone.
These are just threaded PVC fittings that I glue 3/4” pipe directly to it.

And Pentair finally responded. There is not another impeller’s either the one I have or the one from 96.

So after being in the house for a week, I knocked off the Zodiac connector while brushing the pool. I replaced it and didn’t notice the color disc that was in the old one, so I just stuck one in there. The Polaris was working so I just threw the other disc away. Really.....why would I need to keep it?!:roll: Now I know why........

So I just ordered a new Zodiac connector as I’m quite certain I’ll knock it off again soon. Then I’ll have the discs I need.