Changing 1-speed pump motor to 2-speed; slightly complicated

katep

New member
Jun 23, 2010
2
Hi all, Just want to say thank you to this forum. I've lurked for a long time and have learned enough to take care of my pool all by myself (and it is a WHOLE lot nicer, since it is no longer locked up with stabilizer). That alone has saved me $50/month in idiot pool-guy fees, and my pool is no longer stabilizer locked requiring massive amounts of chlorine to boot :)

I've done a bit with my plumbing so far, the idiots at the local pool store also installed a new pool pump (the last one died a heinous and sudden death, which was probably just the motor but I wanted an "energy efficient" pool pump so I sprang for the big $$$). But the new (~2 years old) pump is WAY too powerful for my pool and still sucks up obscene amounts of electricity. It is a Super II 1.5HP energy efficient (SP3015EEAZ so effectively 2hp). I want to change the pump since this thing costs me $100/month to run it a reasonable amount; and even more in the summer when we are actually using the darn thing (and electricity rates are up)!!! I do have a spa which we rarely use and actually the jets are too powerful already, and certainly doesn't justify the insane cost of running 2HP almost all the time. I also have too much head because the pool pipes although 2" are a tangled mess and there is no good way to correct the situation short of digging up all the concrete in the pool area. So it all seems perfect for a 2-speed pump. Yes, a Variable-speed would be even better but I'm trying to do this on the cheap, and would like to re-use the wet end of my still-very-new pump.

So I believe I want to get a new 2-speed motor and also downsize at the same time. According to the SP3000X pump users manual at http://www.pool-pumps.com/pdf/Hayward-S ... Manual.pdf , the housing and everything is the same and I can change to a SP3010x152AZ motor (max-rated 1.5HP) if I also change the impeller, diffuser and wear ring. The AO Smith STS1152R is a compatible 56J 2-speed 1.5hp motor alternative that is cheaper. I think that all looked great except...

I only have 115V feeding the pool equipment. Other outlets and equipment are also on this circuit, so I can't just convert it to 230V, which is what the SP3010x152AZ and STS1152R require. On the AO Smith website, it appears that the AO Smith B969 is an equivalent 115V 2-speed 56J 1.5HP motor to the STS1152R and thus the SP3010x152AZ. It sounds like it should work, if I match the impeller/diffuser/wear ring.

Or am I completely confused and clueless???

My other question is regarding whether I really need a fancy controller if I actually manage to get this new motor installed, or can I just leave it on low speed all the time unless I want to use the spa or vacuum (all which I'm happy to change over manually). Will this pump motor be able to successfully start up in low speed or do I need to pay out $$$$$ for a fancy controller?

Oh, and one more question... do I even need 1.5HP for this set-up and how do I tell? The current pump/motor combo maxes out pressure when run through the spa with a brand new clean filter, which I think means the pump is too powerful for the restrictive spa. Is there any way to know if 1.5HP is still going to be too much? There isn't a 1hp 115V 2-speed pump, the next smaller size is 3/4HP, which is a lot less than we have now. Or could I just downsize the impeller instead? Or should I even get into that much complication??

Thanks very much for any input anyone is willing to give!!!

Kate
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,379
Pleasanton, CA
A much less expensive option would be to just change the impeller/diffusor/ring. A 1.5 HP motor will work fine with a 3/4 HP impeller and won't use any more electricity than if you changed the motor as well. The current draw of a motor is determined by the impeller not the rating of the motor. So the 1.5 HP should draw no more power than a downsized motor.

However, if you want two speeds, then you will have to change the motor as well.
 

katep

New member
Jun 23, 2010
2
Don't you think the lower draw on a 2-speed (0.2HP/4.4Amps on the B969) would save me enough to justify the price difference for the motor (~$300). I'm on Southern California Edison, so the pool costs $0.29/KWH for the summer. Also, do you think 3/4HP would be enough to run a spa and vacuum?

Kate
 

svenpup

LifeTime Supporter
Nov 18, 2009
835
Sacramento, CA
I just did a similar conversion (check my signature for specifics) and am very pleased. I went with the TightWattII timer, but there is no reason you couldn't wire up a switch to control high/low.

If you decide to go that route, don't forget to replace all the seals and o-rings including the shaft seal.
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,379
Pleasanton, CA
Sorry, I missed the part about the spa jets. A 3/4 HP would probably more than enough for a cleaner assuming you can adjust the flow rates to the cleaner but for spa jets, probably not. A better option then might be just a motor swap out to a two speed so when you are not using the cleaner or spa, you can run on low speed.

A 1 HP might be enough for the spa jets but I doubt it. It would probably be quite weak going through the filter. How many jets do you have and what is the recommended flow rate per jet?
 

robinasu

Active member
Jun 23, 2014
38
CA
I just did a similar conversion (check my signature for specifics) and am very pleased. I went with the TightWattII timer, but there is no reason you couldn't wire up a switch to control high/low.

If you decide to go that route, don't forget to replace all the seals and o-rings including the shaft seal.
How's the B2980 treating you? I'm considering it. What impeller size are you using?