Impeller Ratings

[Zurak]

What is the THP for the following Hayward TriStar impellers:

SPX3220C
SPX3215C
SPX3210C

 

[JamesW]

SPX3205C = 1.0 hp

The SPX3207C will work with a 1.25 hp total motor.

The SPX3210C takes a 1.65 total hp motor.

SPX3215C = 2.2 hp

SPX3220C = 2.7 hp.

https://www.pooltek.com/wp-content/uploads/2017/02/Pump-HaywardTriStar.pdf

 

[Zurak]

SPX3205C = 1.0 hp

The SPX3207C will work with a 1.25 hp total motor.

The SPX3210C takes a 1.65 total hp motor.

SPX3215C = 2.25 hp

SPX3220C = 2.7 hp.

View attachment 548448

View attachment 548449

https://www.pooltek.com/wp-content/uploads/2017/02/Pump-HaywardTriStar.pdf

Thank-you for the information.

When I look at an Amazon listing for the SPX3215C (Amazon.com) impeller, the description states for use with:

sp3205ee,
sp3207ee,
sp3210ee,
sp3215ee,
sp3220ee

models. Is the information wrong?

INYOpools calls SPX3215C a 2 HP impeller (Hayward TriStar 2 HP Impeller with Screw - SPX3215C - INYOPools.com)

When I view the 2nd chart you provided, it states the SPX3215C is an Impeller for a 1-1/2 HP with Impeller Screw (no discernment between Max and Full Rate).

I don't see where the HP rating for the SPX3215C would be 2.25 HP.

What am I missing? I would like to understand.

 

[JamesW]

When I view the 2nd chart you provided, it states the SPX3215C is an Impeller for a 1-1/2 HP with Impeller Screw (no discernment between Max and Full Rate).

The 1.5 hp full rated pump is listed as 2.4 total hp.

However, the same impeller (SPX3215C) is also used on the 2 hp Max rate, which takes a 2.2 hp total.

The manufacturer used to have a lot of discretion in how motors and pumps were rated before the new rules were changed to require that only the total hp be used.

The whole rating system was horrible and confusing.

Getting rid of "Service Factor" for motors.

Does service factor have any value? In my opinion, it has no value. In fact, I think that it only causes problems and confusion. The only number that really matters is the Total HP of the motor. Motor makers make two identical motors and label one as 1 hp with a 1.65 service factor and the...

www.troublefreepool.com

In any case, the SPX3215C should use a 2.25 hp total hp motor.

 

[Zurak]

The 1.5 hp full rated pump is listed as 2.4 total hp.

However, the same impeller (SPX3215C) is also used on the 2 hp Max rate, which takes a 2.2 hp total.

The manufacturer used to have a lot of discretion in how motors and pumps were rated before the new rules were changed to require that only the total hp be used.

The whole rating system was horrible and confusing.

Getting rid of "Service Factor" for motors.

Does service factor have any value? In my opinion, it has no value. In fact, I think that it only causes problems and confusion. The only number that really matters is the Total HP of the motor. Motor makers make two identical motors and label one as 1 hp with a 1.65 service factor and the...

www.troublefreepool.com

In any case, the SPX3215C should use a 2.25 hp total hp motor.

Is the correct approach to look at the Pump Skew Detail (on Page 11) in the attachment you provided "Pump-HaywardTriStar.PDF", for the "Impeller P/N" for the SPX3215C which appears on multiple lines for the following motor P/N. I then looked up the nameplate for the motors:

spx3215z1ber HP=1.5, SF=1.6, THP=2.4 (Full Rate)
spx3215z2ber HP=1.5, SF=1.6, THP=2.4 (Full Rate)
spx3215z1mr HP=1.5, SF=1.6, THP=2.4
spx3215z2mer HP=2.0, SF=1.2, THP=2.4 (Max Rate)

All state 2.4. THP, so I am having trouble finding the 2.25 THP value. What am I missing?

 

[JamesW]

2.00 x 1.10 = 2.20.

This shows that a 2.2 hp motor is acceptable for the SPX3215C Impeller.

Hayward Motor, 2hp Maxrate Tristar 115/230v (SPX3215Z1MR) - INYOPools.com

"MOTOR, 2HP MAXRATE TRISTAR 115/230V" (SPX3215Z1MR) - Pool & Spa Parts

www.inyopools.com

 

[Zurak]

2.00 x 1.10 = 2.20.

This shows that a 2.2 hp motor is acceptable for the SPX3215C Impeller.

View attachment 548484
View attachment 548483

Hayward Motor, 2hp Maxrate Tristar 115/230v (SPX3215Z1MR) - INYOPools.com

"MOTOR, 2HP MAXRATE TRISTAR 115/230V" (SPX3215Z1MR) - Pool & Spa Parts

www.inyopools.com

The confusing part for me is that INYOpools also has the same motor number listed twice Hayward Motor, 1-1/2hp Full, Tristar, 115 208-230v Single Speed, SPX3215Z1BER, HSQ1152, SP3215Z1BE, SPX3215Z1MR, SP3215Z1MR - 5112-256 - INYOPools.com as a 2.4 THP

and as a 2.2 THP that you found,

So the SPX3215C is a 2.2 THP impeller that can work on larger THP motors but not on anything smaller than a 2.2 THP motor

 

[JamesW]

So the SPX3215C is a 2.2 THP impeller that can work on larger THP motors but not on anything smaller than a 2.2 THP motor

 

[JamesW]

Help Choosing Hayward SP3215X20 Impeller

I am in need of replacing the impeller on my SP3215X20. It has a 2HP "Max Rated" motor. The current impeller in it is a SPX3215C. However, in the manual (https://www.hayward-pool.com/assets/documents/pools/pdf/manuals/TriStar.pdf), it lists this part as being a "Impeller for 1 ½ HP with...

www.troublefreepool.com

Hayward SP3215X20 TriStar Single-speed Max Rated 2 HP Pool Pump.

 

[JamesW]

The SP3215X20 is listed as a 2 hp Max Rated pump with a h.p of 2.0, a S.F (Service Factor) of 1.1 and a total hp of 2.2 (total hp = rated hp x S.F)

The SP3215EE is listed as a 1.5 hp Full Rated pump with a rated h.p of 1.5, a S.F (Service Factor) of 1.6 and a total hp of 2.4 (total hp = rated hp x S.F)

Note that these two pumps are the same exact pump in every detail except the label.

They use the same impeller.

 

[JamesW]

In my opinion, the 2.4 HP rating was never a valid rating.

They do the same thing with the 1.65 max rate and the 1.85 hp full rate, but the 1.85 hp is just a marketing gimmick and not a real value.

 

[Zurak]

Or is it a 1-1/2 HP impeller that can work on larger i.e. 2.2 THP or 2.4 THP pumps? Why would Hayward state that it's a 1-1/2 HP impeller if it was not?

 

[JamesW]

Why would Hayward state that it's a 1-1/2 HP impeller if it was not?

Ask Hayward why Hayward would say that it's a 1-1/2 HP impeller if it isn't a 1-1/2 HP impeller.

Contact Us

hayward.com

Also, the subject was pretty well covered in this thread, which you participated in.

Getting rid of "Service Factor" for motors.

Does service factor have any value? In my opinion, it has no value. In fact, I think that it only causes problems and confusion. The only number that really matters is the Total HP of the motor. Motor makers make two identical motors and label one as 1 hp with a 1.65 service factor and the...

www.troublefreepool.com

 

[JamesW]

It's my understanding that a motor can operate in it's SF when it's needed as a result of the following:

(1) Filter that is getting dirtier, (2) leaf, skimmer or pump baskets filling with debris, (3) water features or in-floor cleaning systems, (4) dust and/or blocked ventilation holes, etc ...

It's really not desirable to operate the pump in it's SF. A pump with a lower rated HP and higher SF will often be cheaper than a pump with a higher rated HP and lower SF. Operating a pump in it's SF often results in more heat and all it takes is for a 10 degree C (16 degree F) rise in temperature to half the lifespan of the insulation on the wiring in the motor. Is it worth saving a few bucks to shorten the life of your motor?

Continued operation of a motor in its SF will shorten the life of the motor. I would not want to see the removal of the SF from the nameplate.

[FONT=&quot]The [/FONT]service factor (SF) [FONT=&quot]is commonly misunderstood as an allowable overload for electric motors. For example, you may find a 100-hp motor with a SF of 1.15 driving a 110-hp load, under the incorrect assumption that it tolerates up to 115 hp. However, motor operation under these conditions leads to many performance issues down the road.

Even if a motor has a SF above 1.0, it should never be operated above rated horsepower continuously. In fact, even intermittent operation above rated HP is a mistake if you are doing it intentionally. The SF indicates the overload that a motor can tolerate without damage, as long as the it occurs under [/FONT]normal operating conditions:

• Rated voltage
• Rated frequency
• Ambient temperature below 40°C
• Altitude below 1000 m

[FONT=&quot]A motor running continuously within the overload range allowed by the SF can suffer a reduction in efficiency, RPM and service life. In other words, the SF is intended for unpredictable and brief overload conditions, not for continuous operation or intentional short-term overload.

Strictly speaking, the service factor was developed by the National Electrical Manufacturers Association (NEMA) with the following purposes:
[/FONT]

• Applications where horsepower needs are subject to variations that cannot be estimated accurately.
• Increasing the service life of motor insulation, by reducing the operating temperature at rated horsepower.
• Providing tolerance for intermittent or occasional overload conditions.
• Tolerating brief ambient temperature peaks above 40°C.
• Tolerating under-voltage or voltage imbalance.

[FONT=&quot]To summarize, the service factor provides an operating margin for motors subject to unpredictable and brief load increases. In addition, it helps the motor tolerate brief temperature peaks or voltage issues. The horsepower margin allowed by the motor service factor should not be used intentionally, not even for intermittent applications.
By way of an analogy, we know that chip manufactures will sometimes use a higher rated product and label it to sell as a lower rated product. This is perfectly acceptable and a savvy consumer who knows this can save some money. But the manufacture will never take a lower end product and purposely label it as a higher end product as the product will often fail in the intended application and the manufacturer will be sued.

That's why SF will always be on the name plate and making incorrect assumptions about it can lead to a shorter service life of the motor. If you have a letter from a manufacturer stating otherwise, please share it.

[/FONT]

Your 2nd link has the following information inside:

The best procedure in replacing any motor when an exact match of HP and SF is not available is to multiply the nameplate horsepower of the old motor times its service factor to determine the THP.

Make certain the replacement motor has a maximum horsepower equal to or slightly higher than the old motor.


Handling a continuous load greater than that allowed by the service factor will cause the motor's thermal protection device to trip. If the situation is not corrected, continued operation will eventually damage the motor.


So if you had a 2.0 HP motor with a service factor of 1.35 which would have a THP of 2.7, then replacing it with a 2.5 HP motor with a service factor of 1.08 and a THP of 2.7 would be a step in the right direction (provided that the voltage/amperage did change significantly)

The corollary however is not true, that is you cannot take a 2.5 HP pump with a service factor of 1.08 and replace it with a motor that has a 2.0 HP rating and a service factor of 1.35 without affecting performance. Even Century states that Service Factor is still very important and operating a pool motor continuously in the Service Factor will eventually damage the motor.

Multiplying Rated HP x SF is a guide and should not be used as an absolute. It can be a first step in finding a replacement motor but if you are not careful it will lead to a shortened lifespan of the motor.

Here's a link to an article titled: The Fundamentals of AC Electric Induction Motor Design and Application. http://www.enginuitysystems.com/files/p20pg095 (Motor design).pdf

It's written by two Electrical Engineers with many years of experience between the two of them. On the 4th page of the PDF (page 98 on the text) is a definition for Service Factor, which I will copy here & italicize the crucial statement about operating in the S.F. continuously.

Service factor -- The service factor (S.F.) is required on a nameplate only if it is higher than 1.0. Industry standard service factor includes 1.15 for open-type motors and 1.0 for totally-enclosed-type motors. However, service factors of 1.25, 1.4 and higher exist. It is not considered good design practice to use the rating afforded by S.F. continuously; operating characteristics such as efficiency, power factor, and temperature rise will be affected adversely.

Here's a link to a 2nd PDF that talks about Service Factor and the popular misconceptions regarding it:

http://www.avonmore-electrical.com/contentfiles/Service Factor - What is it and What does it do.pdf

It's a 2-page article that states "A motor operating continuously at any service factor grater than 1 will have a reduced life expectancy compared to operating at rated nameplate horsepower. Insulation life and bearing life are reduced by the service factor load.

The first link that James provided: https://www.centuryelectricmotor.com...I-20130621.pdf only states that the two motors have the same THP and a careful reading of the label shows they have the same amperage. If you couple this with what we know about SF and that one should not run a motor with an SF greater than one continuously then we can deduce that the 0.75 HP x 1.65 SF motor can be replaced with the 1.0 HP (rated) x 1.25 SF since the THP is the same. It says nothing about going in the opposite direction.

The 2nd link that James provided: https://www.centuryelectricmotor.com/News-Detail.aspx?LangType=1033&id=6442451535 provides an example for replacing a failed 3/4 HP motor with a service factor of 1.25 (THP = 0.938)

The motor suggested (Motor C) has a rated HP of 1.0 (greater than the original 0.75 rated HP motor) and a service factor of 1.0 for a THP of 1.0 horsepower. Again the example is taking the replacement in one direction. The corollary is not true because one would be relying on overloading the motor which is okay for temporary conditions but not for continuous operation.

Unfortunately there are many pool store sales people who also repeat the Rated HP x SF mantra and sell unsuspecting customers a motor or pump that just won't last as long. Clearly Century's "white paper" doesn't help as it's not as clear as it should be, so a consumer either takes them at their word, does a google search & lands on this site and/or does more reading and some of the reading is very technical and requires an engineering degree to understand.

As I read the first Century link all I can infer is that two motors have the same THP and Voltage/Amperage values. I can see the argument in one direction but based on what is known about the Service Factors, cannot support the claim that both motors are substitutes for each other as clearly going from the lower SF to the higher SF would cause the motor to be running in an "overload" condition and if done continuously then cause it to fail prematurely.

To suggest that Service Factor can be ignored completely is an assumption that I cannot make. It's there for a reason, namely to show how hard the motor can be run in a temporary overload condition, not in a continuous state. The examples that Century provide are in one direction only.

Here are a few more articles that discuss Service Factor and what happens if you run the motor in the Service Factor:

(1) What You Need to Know about "Service Factor"
(2) https://thegrid.rexel.com/en-us/kno...tanding-the-service-factor-of-electric-motors

"[FONT=&quot]the service factor provides an operating margin for motors subject to unpredictable and brief load increases. In addition, it helps the motor tolerate brief temperature peaks or voltage issues. The horsepower margin allowed by the motor service factor [/FONT]should not be used intentionally[FONT=&quot], not even for intermittent applications."

If you go back and look at the Example in the 2nd Century "white paper", the suggested replacement motor (i.e. Motor C) has a SF of 1.0 and the motor would not be operating in the SF. If you started with Motor C and ended up with the "failed motor" as an equivalent substitution, you'd end up with a motor that has an SF of 1.25 and that motor would be operating in the SF all the time to deliver a nearly equivalent THP. Put another way, the Service Factor is there to account for temporary issues that might be occur. Again, Century (Regal Beloit) could have done a better job in their article and "white paper". [/FONT]

It all comes down to how you wish to read or interpret an article or technical paper on motors. If you approach it without knowledge of what the Service Factor is, you can infer that you can swap motors so long as the Total Horsepower i.e. the product of the rated horsepower & service factor is the same.

However if you read the same article/White Paper with the knowledge that a motor or pump should never be operated continuously in the Service Factor because the Service Factor is a fudge factor designed to account for varying conditions outside the norm, then the article & technical paper only make sense if you apply the substitution in one direction, namely in one that does not ignore the Service Factor.

Lastly, we don’t know the motives of Century in their article/white paper. We can perhaps add that many pool companies that build pools may not have the technical expertise to calculate Total Dynamic Head and therefore may overestimate the needs of the motor. So if a consumer starts out with a motor that is larger than what is required and follows the first Century article and substitutes a motor with a one that has a smaller rated horsepower but a larger Service Factor, they may indeed get lucky and not notice a reduction in the service life of the motor. All this of course is speculation & not science, so I can only conclude that the Century article/white paper should be taken with a grain of salt as it bucks the definition of Service Factor.

The Cowern papers offers the following on the topic of Service Factor:

Page 11:

The question often arises whether to use service factor in motor load calculations. In general, the best answer is that for good motor longevity, service factor should not be used for basic load calculations. By not loading the motor into the service factor, the motor can better withstand adverse conditions that occur. Adverse conditions include higher than normal ambient temperatures, low or high voltage, voltage imbalances, and occasional overload. These conditions are less likely to damage the motor or shorten its life if the motor is not loaded into its service factor in normal operation.

Page 19:

By taking a Class B, totally enclosed fan cooled, T frame motor, and building it with Class F insulation, it is usually possible to increase the service factor from 1.0 to 1.15. As mentioned previously, this same change of one insulation class can be used to handle a higher ambient temperature or to increase the life expectancy of the motor. The same change could also make the motor more suitable for operation in high elevations where thinner air has a less cooling effect.

Is Cowern wrong here? Who should a pool owner believe? Does a pool owner have to have an engineering degree to understand the concept of Service Factor?

By way of an analogy. Many people have no idea how an automobile engine or a transmission works, but it doesn't stop them from learning how to dry and knowing that they must have gas in the tank, oil in the engine and air in the tires in order to drive. If the experts in the industry including Cowern state that motors should not operate in the Service Factor, are they wrong? If so, why?

I looked at the owner's manual for the Hayward EcoStar & Tristar pumps and at least in the two manuals that I looked at the wet end is common to both. The pumps were offered with various motor from 1/2 HP to 5 HP. For one particular motor that had a rated HP of 2 and a service factor of 1.35 the total HP was 2.7. Another motor had a rated HP of 2.5 and a service factor of 1.08 for a total HP of 2.7, yet both required a different impeller. If the two motors were identical one would think that the impeller would be the same in both cases and it's not.

Perhaps a pool builder overestimated a motor for an initial installation. 8 or 10 years later a consumer now has to replace that motor and finds its no longer made. It's been suggested that one only needs to know the THP and choose a replacement pump based solely on that. That flies in the face of what the experts in the industry have to say about Service Factor. Again, who to believe?

In the case of the Pentair replacement motors for the WFE-4 and WFE-26 the SF goes from a high value to a low value which to me is consistent with a desire to keep the motors operating outside of the Service Factor. I also found a Century Centurion BPA450V1 listed as a replacement motor (see: Pentair 355010S, 071314S 1 HP Almond Replacement Motor, Single Speed) and it has a Rated HP of 1.65 and a SF of 1.00, again consistent with a desire to keep the motor operating outside of the Service Factor.

In the case of the Hayward replacement motors for the Tristar, two motors, one rated for 2.0 HP and a SF of 1.35 (2.7 THP) and a 2.5 HP with a SF of 1.08 (2.7 THP) call for different impellers. So no conclusion can be reached to support that the two motors are the same.

Yes, the Hayward EcoStar is a Variable speed based pump, but so is the TriStar which has single, dual and variable speed motors available and both the EcoStar and the TriStar share the same wet end.

From all of this I cannot support the conclusions that you or mas985 have reached that one can ignore the SF and just look at THP. And even if I could, the replacement motors in the case of the Pentair go from a high SF to a low SF & not the other way which goes back to the Century article & White Paper which only show examples in one direction (high SF to a low SF).

At this point I believe that we agree to disagree. Since I am spending money on a replacement motor I will err on the side of caution and purchase a motor that is consistent with the notion of a low SF.

I agree that Cowern is not wrong. His statements on Service Factor are consistent with the experts in the industry. And who wouldn't want their motor to run cooler vs. hotter? I suspect it also matters where you live and have a pump (motor). Out here it's not uncommon to have outdoor temperatures near 50 C in the summer. Add direct sunlight and even w/o running the motor it's very hot to the touch. I've had motor housings get so hot that the paint & label have literally bubbled off. Yet, one of my motors managed to survive for 8.5 years which had a low SF. It's replacement (coincidentally one with a higher SF and slightly higher THP) only lasted 2 years and 2 months. As I stated to JamesW, I am going to err on the side of caution and purchase a replacement motor that has a low (near 1.0) SF.

I think that's a great idea Chris, and although it hasn't happened to me yet, I will do that when I install the replacement motor. I have gotten into a habit of replacing the seals once a year (cheap insurance) given that our desert climate seems to accelerate wear & tear on things out here including pool motors in particular. Our ambient temperatures can approach 50 C (over 120 F) in the summer and I've seen the paint/label bubble off the motor housing on the motors that last over 5 years. It also seems that the older motors (those over 10 years) generally last much longer than the newer motors. I did find a local shop that rebuilds motors so that is also an option.

 

[Zurak]

Ask Hayward why Hayward would say that it's a 1-1/2 HP impeller if it isn't a 1-1/2 HP impeller.

Contact Us

hayward.com

Also, the subject was pretty well covered in this thread, which you participated in.

Getting rid of "Service Factor" for motors.

Does service factor have any value? In my opinion, it has no value. In fact, I think that it only causes problems and confusion. The only number that really matters is the Total HP of the motor. Motor makers make two identical motors and label one as 1 hp with a 1.65 service factor and the...

www.troublefreepool.com

Ask Hayward why Hayward would say that it's a 1-1/2 HP impeller if it isn't a 1-1/2 HP impeller.

Contact Us

hayward.com

Also, the subject was pretty well covered in this thread, which you participated in.

Getting rid of "Service Factor" for motors.

Does service factor have any value? In my opinion, it has no value. In fact, I think that it only causes problems and confusion. The only number that really matters is the Total HP of the motor. Motor makers make two identical motors and label one as 1 hp with a 1.65 service factor and the...

www.troublefreepool.com

I will ask Hayward.

The process to examine the recommended impellers for each motor did not answer my question. It only confirmed that the recommended Hayward Impeller would work on their recommended motors.

The description of the Hayward SPX3015C impeller in it's packaging states that it's a 1-1/2 HP impeller which to me means that it can work in all the motors that Hayward recommends but I can't see how it can be inferred that the impeller HP is something that is different then what is stated on the package.

 

[JamesW]

It’s somewhat like a 2 X 4 being called a 2 x 4 when it’s not 2 x 4.

Sometimes a description is “Nominal”, which means that it is a name and not necessarily a technically accurate description.

Also, there are many different ways to describe the “Power” of a pump, motor or impeller.

You have the total maximum power that a motor can be safely loaded to; you have input power, output power, apparent power, real power, reactive power etc.

You also have different power requirements based on the flow and head loss.

Different conditions use different amounts of power.

At the time, you also had a service factor, which further complicated the issue.

So, you have maybe 20 different ways that you can choose from regarding how to label the power of a pump or impeller.

 

[JamesW]

Or is it a 1-1/2 HP impeller that can work on larger i.e. 2.2 THP or 2.4 THP pumps? Why would Hayward state that it's a 1-1/2 HP impeller if it was not?

 

[Zurak]

What do my old posts have to do with my current question? I am confused.

 

[Zurak]

It’s somewhat like a 2 X 4 being called a 2 x 4 when it’s not 2 x 4.

Sometimes a description is “Nominal”, which means that it is a name and not necessarily a technically accurate description.

Also, there are many different ways to describe the “Power” of a pump, motor or impeller.

You have the total maximum power that a motor can be safely loaded to; you have input power, output power, apparent power, real power, reactive power etc.

You also have different power requirements based on the flow and head loss.

Different conditions use different amounts of power.

At the time, you also had a service factor, which further complicated the issue.

So, you have maybe 20 different ways that you can choose from regarding how to label the power of a pump or impeller.

But it seems to me if Hayward made the impeller and is selling it, it would be a lot easier to state what it is on the package (see photo I provided).

Going through a complicated process of figuring out which motors it can be used on then calculating the THP did not help me understand what the impeller's HP was; only that one can put a smaller HP impeller on a larger motor.

Websites that sell it don't do it justice when they change the manufactures description and further complicate things by bringing in Full / Max rate motors that can use it.

We can agree that the Service Factor issue overly complicates things. I have seen century place an oval sticker stating the pumps Total Horsepower which I think was a step in the right direction.

Thank-you for taking the time to answering my current question. I fail to understand what my previous comments on other posts have to do with my current question.

 

[JamesW]

What do my old posts have to do with my current question? I am confused.

My point is that the thread covered the issue pretty well and your posts indicate that you understand the issue pretty well.

In any case, you are asking me why Hayward does something a specific way.

If you want to know why someone says or does something, ask the person saying or doing the thing.