Replacing a motor on a pump, and getting the correct size for your pool?

[mitchryan912]

I'm leaning towards buying this replacement motor, an AO Smith USQ1102: http://www.amazon.com/Smith-USQ1102-.../dp/B007ATO2SK

It seems like it's direct replacement for the US Motors 1081 that was part of the Waterway pump we have.

[mas985]

First the whole concept of turnover for residential pools is flawed (see pump run time study in my sig). There is no minimum turnover required for a residential pool so minimum flow rates are really only important for things such as heaters and SWGs and SPAs so you really don't need to bother trying to figure it out unless you have one of these features.

But if you are going to the trouble of replacing a motor, I would get a two speed. Assuming you have a 48Y square flange motor, then you could use a UQS1102R motor but you will need to buy a 3/4 HP full rated impeller for the pump.

When the pump is running, it typically reads 55-60 psi,

That is impossible. You filter gauge is broken.

While we're at it, my pump runs 24/7.

No need to. A pool can get by with as little as 2 hours of run time (see study).

[CarlD]

I run my pool 12hrs/day at low speed (about 1/4hp) for two reasons:
1) I have an SWCG
2) I have solar panels that are also the decking and when the pump is running it keeps the decking cool while it heats the water.

O/W I'd run it just enough to keep it skimmed and clean.

[mas985]

I too have solar and an SWG but run for only 4 hours per day. I could drop it to 2 hours per day if I didn't need to run solar because the SWG is large enough to do that. In fact, in the winter, that is exactly what I do.

[CarlD]

Well, my solar is decking so it's more to keep the deck cool than to heat the water.
In the winter, my pool can have 12-18" of ice in one giant berg!

[mitchryan912]

But if you are going to the trouble of replacing a motor, I would get a two speed. Assuming you have a 48Y square flange motor, then you could use a UQS1102R motor but you will need to buy a 3/4 HP full rated impeller for the pump.

Would this be it? http://www.amazon.com/Smith-SQS1102R...ao+smith+1102R

It's a 1/.166 HP 2 speed motor. Since the full speed of 1 HP is the same as the impeller I have, would I be able to keep that the same?

That is impossible. You filter gauge is broken.

Yep, I noted where it is when there's no pressure, and subtracted that from what it reads when there is full pressure (about 25 psi.) Since the system is down, I'll take the time to replace that.

No need to. A pool can get by with as little as 2 hours of run time (see study).

If I were to go with a single speed motor like I linked above, could I install a timer inline with the motor and still see energy savings?

[mitchryan912]

Also: is the wiring different on a two-speed motor? How do you control the speeds? I don't see any switches or controls on the motor.

[mas985]

The SQS1102R is a full rated 1 HP and larger than you need. You need a 1 HP up rated motor (UQS1102R) OR a 3/4 HP full rated motor (SQS1072R) which have an identical 1.25 THP rating.

Yes, you could just get a single speed and run it shorter to save energy but a two speed will save more over the life of the pump and motor. To control a two speed, you can use a manual switch or a two speed timer. Which option you go with depends on how much money you want to spend up front but no matter what, you will make that money back with energy savings.

[mitchryan912]

The SQS1102R is a full rated 1 HP and larger than you need. You need a 1 HP up rated motor (UQS1102R) OR a 3/4 HP full rated motor (SQS1072R) which have an identical 1.25 THP rating.

OK, I think I get it now. I think I'm leaning toward the SQS1072R, as I'm seeing some places say the UQS1102R has been discontinued (looks like HSQ125 is the replacement?) If I went with the SQS1072R, would I need a new impeller and/or diffuser? What about with the UQS1102R or HSQ125?

Yes, you could just get a single speed and run it shorter to save energy but a two speed will save more over the life of the pump and motor. To control a two speed, you can use a manual switch or a two speed timer. Which option you go with depends on how much money you want to spend up front but no matter what, you will make that money back with energy savings.

Any recommendations on two speed timers, or could something be built from standard electrical parts? I'm a former electrician, so I can wrap my head around the electrical side of things.

[mas985]

If I went with the SQS1072R, would I need a new impeller and/or diffuser? What about with the UQS1102R or HSQ125?

HSQ125 may be an issue because of the back end. I can't guarantee that would fit on the motor support.

As for the impeller, it depends on the service factor of your current pump motor. If the current service factor is 1.25 or lower, then the impeller is fine. Diffuser would not change either way.

Timer:

http://www.amazon.com/Intermatic-T10...W61QF3SM3H6H1T

http://www.amazon.com/Intermatic-PE1...BXFB6W5PGHAXZ5