Pump ?

[WshnIwslofn]

Hi. Good to see this site. I have a Pentair Pinnacle 1 1/2 hp single speed pump that old owner left to replace bad pump with. Before I replace it, wanted to know if it would really be worth it to change the motor to a dual speed? Checked on-line and the motor would probably be as much as the cost of the single speed! Can you replace this motor for Pentair with good results and is there a reputable company out there? Read a lot of the good of dual speeds on Pool Forum. I have a 16 x32 in-ground vinyl with a portable hot tub so the hp is correct.
Thanks
Kay

 

[JohnT]

1.5HP is too big for that pool. You could easily get by with a 1HP pump and you could probably use a 3/4HP pump. Big waste of electricity, and if your filter isn't sized for that pump, you will have problems. A 2-speed pump is a great idea, and can save money while giving you the capability to speed things up when you need to.

 

[Guest]

The Pinnacle is actually an uprated pump so it is really a 1 hp pump. There is a numbers game that all pump manufacturers play with pumps. There are full rated pumps and uprated pumps. They take the HP rating of the motor and multiply it by a service factor number to get the brake HP. Brake HP is the actual HP rating of the pump. The service factor is really how much power is left under an extreme load. Uprated pumps have a lower service factor than full rated pumps For example. a fullrated 1.0 hp pump has a motor HP rating of 1 and a service factor of 1.65. When this is multiplied you have a brake HP of 1.65. An uprated 1.5 HP pump will have a HP rating of 1.5 and a service factor of 1.1. Multiply these and you also get 1.65 brake HP! If these two pumps are in the same manufacuturer's model line they are exactly the same pump with the same impeller, volute motor, etc. The only difference is the numbers written on the pump and possibly the price! They are both 1 hp pumps! One is just rated more conservatively (and IMHO, accurately) than the other! The Pinnacle line are all uprated. Your model has a HP rating of 1.5 and a service factor of 1.1 for a brake HP of 1.65! I would not recommend replacing the motor with a dual speed one. It will cost you almost as much as a new pump would and the pump might not perform properly at low speed since the impeller and volute were not designed to run that way. All pump motors are made by AO Smith, btw!

 

[WshnIwslofn]

Thanks for your replies.
So you are saying that I am ok with my 1hp uprated pump for my pool and HT. Am I paying more electric costs because it says 1 1/2hp when it is really only a 1 uprated?
Kay

 

[JohnT]

Thanks for your replies.
So you are saying that I am ok with my 1hp uprated pump for my pool and HT. Am I paying more electric costs because it says 1 1/2hp when it is really only a 1 uprated?
Kay

Electric motors will try to turn a load like a pump even if they are vastly undersized. The HP that a motor is capable of producing is a function of its input power and wire size used in construction. If you overload a motor, the shaft can't turn and the excess current flowing in burns up the wires and melts things inside the motor. This lets all the smoke out, and once you let the smoke out, the motor is trash.

Uprated is an industry term that states how close you are operating the motor to the overload point where it will overheat and burn up. If the SF is 1, you don't have any slack. An SF of 1.15 means you can operate at 15% over the plate HP rating without problems. The appropriate SF for a motor in a particular application is a design decision that is made based on how likely the motor is to experience higher than rated load during use (and ambient operating temperatures), and how much over the rated capacity that load will likely be. Pool pumps are traditionally sized with 25% to 40% extra capacity or a SF of 1.25 to 1.40. The lower SF motor just can't handle extra stress like clogged filters etc. as well as one with a higher SF.

As to the electricity issue, every motor has a sweet spot where it is most efficient. This is usually somewhere near maximum load, so an uprated motor may actually be slightly more efficient than one that is at the normal SF for an application.

As to whether you can use that motor, you need to see what volume of water that motor can pump at your system's head, and then see how much flow your filter can handle.

 

[WshnIwslofn]

The guy we bought the house from, as we were leaving from the closing, said go to pool forum, when we asked him about the pool directions he was going to give us! Hopefully the new pump he left us was bought because of the knowledge he got from pool forum!! I'll have to verify.
Also I remember seeing Carl's equipment setup in a picture. Can anyone tell me where that was on pool forum. Since I was replacing the pump, thought I might try the flexible hose.
Thanks
Kay

 

[Guest]

Thanks for your replies.
So you are saying that I am ok with my 1hp uprated pump for my pool and HT. Am I paying more electric costs because it says 1 1/2hp when it is really only a 1 uprated?
Kay

you have a 1.5 hp uprated pump which would be equivalent to a 1 hp full rated pump. The Pinnacle line by Pentair are all uprated (a common practice for many manufacturers since it makes the pump seem to be more powerful than it's competitors for the price. This is why HP ratings are not as important as pump performace curve graphs.) If you look at their Whisperflo line it includes both full rated and uprated pumps. In that line the 1 hp full rated is EXACTLY THE SAME PUMP with the same performance curve, motor, volute, impeller, etc. as the 1.5 hp uprated one. The only difference is the nameplate with the specs that is glued on the motor and the price! (uprated pumps are often priced lower or higher than the equivalent full rated one for some reason even though if you look at the parts list they are built from exactly the same parts.)

 

[WshnIwslofn]

Thanks. You'll be hearing from me again!
Kay