SWG with a 2 speed pump

[Pool virgin]

All, I am replacing my 2 hp single speed pump motor due to a bad bearing. (I was going to just replace the bearing but during the motor surgery I realized how bad the motor was and decided to just replace it) I have a SWG and want to go to a 2 speed to save on energy costs. Are there any issues with running the pump on low speed with the SWG? Also, I am assuming I do not have to change any of my pump parts if I purchase a direct replacement motor with the only change being 2 speed.



15k gallon, gunite pool with SWG and cartridge filter (just bought house so dont have any particulars on the filter or SWG yet)

 

[DaveNJ]

I run mine on low speed most of the time. Do have to set valves so there is sufficient flow at the SWCG. Once its set I don't change the valve positions often. Marked the valve positions so I can return them to the normal every day use position.
Can't give advice on the motor replacement.

 

[spishex]

If you are matching the motor's HP and SF you're ok. If you get a lower HP with the same SF you'll need to downsize your impeller. If you get a higher HP motor you can use the same impeller but will get no benefit from it. Long story short: your impeller size is matched to your motor size.

Assuming you get the same HP/SF motor then you'll need a new shaft seal and you might consider new housing and diffuser o-rings depending on your pump.

 

[JasonLion]

The SWG needs some minimum flow rate to work correctly. Most of them will turn off automatically if they aren't getting the flow rate they need. Given that you have a 2 HP motor, it is quite likely that you will have a high enough flow rate on low speed. The actual flow rate depends on many details of your plumbing and how dirty the filter is, so there is a small chance you will not get sufficient flow.