Plumbing mistake causing $$$ electricity?!!

[addajio]

Hi all, I have received much good info here and as a newly Registered Member would like to thank you all for helping others, which helped me.

I now have a problem that I think I know the answer to, but lack the experience, so where better to ask for help.

I replaced a very old 2 HP Pump/Motor last Oct. with a Pentair Superflo 1 HP Pump/Motor. Installed and wired easily, except it was longer overall
and caused me to ignore the 5 X Pipe Diameter [2"] = 10" length of pipe recommended between the 90 degree fitting and the Pump Inlet [see pic].
The Suction created and water pressure coming in thru the returns was waayyyyy higher than any previous pump [my first clue]. The Kreepy Krauly went so fast I had to use an in-line hose fitting to bleed off suction [second clue]. It did however work well. The pump itself is quiet, but sound of the water moving thru the pipes is louder than before [third clue].

Now, the reason for my post is that my last Electric bill was easily $45 higher, and I have not even used the Air Conditioning yet. Nothing else has changed use-wise [I live Alone and
know my usage].
I looked at bills going back to Oct, and all were 20 to 30% higher. The Picture shows the present install/mistake.
Is this the reason for the higher bills and the louder operating noise and should I re-Plumb for this or other reasons?

Thank - Tony

 

[jblizzle]

Welcome to TFP!!!

The plumbing as nothing to do with the supposed higher electrical cost.
You are moving more water, which requires more electricity.
Also, the 10x pipe length is not very important with newer pump designs.

HP is not the only factor when comparing pumps. There is also a service factor on the motor and the wet end design.

How long are you running the pump? Don't run as long and save money. It would have been wise to have gotten a 2-speed version of that pump.

Check out:Determine Pump Run Time

 

[addajio]

Thanks, Jason!

The reason I suspect the plumbing is...well, imagine if you disconnect a section of the vacumn hose [underwater] , and put your hand over it - you hear the motor strain to draw water from the blocked hose. I thought maybe something similar was causing the motor to work harder and thus draw more Amps trying to counter-act some flow problem. As I said, there is a LOT more Suction on the Cleaner, and much higher Return Pressure - I know as I've been tending this pool since 1989.

You said" You are moving more water, which requires more electricity."

How So? Because the Superflo is "newer pump design"?


I run the Pump 1 Hour for every 10 Degrees Temp...right now 9 - 10 Hours in Scottsdale.

-Thanks again

 

[jblizzle]

That is way more pump run time than you need.

Sure the pump design may have changed, but generally what I said is true. You are going to use more power to move more water.

 

[Isaac-1]

Pumps are one of those things that defy common sense like working harder when there is a restriction on the suction side, the reality is they consume less power when they have a suction side restriction.

 

[addajio]

Pumps are one of those things that defy common sense like working harder when there is a restriction on the suction side, the reality is they consume less power when they have a suction side restriction.

...wow, that does defy logic. Hmmm with that in mind, do you think I should induce "restriction", as I've got PLENTY of suction?

I admit I am confused as to what to do regarding the inlet pipe.

The Superflo Manual:

"4. It is recommended that a valve, elbow or tee installed

in the suction line should be no closer to the front

of the pump than five (5) times the suction line pipe

diameter"

...and


"Fittings and Valves
1. Do not install 90° elbows directly into pump inlet.

 

[jmastron]

They pump may consume less power when restricted, but will be less effective by a greater factor. For example, a pump that draws 1000 watts and achieves 50gpm unrestricted might when restricted draw 800 watts (20% less) but only achieve 25gpm (50% less). Totally made up numbers, but you get the point.

My interpretation of the Pentair recommendation (and in the IntelliFlo manual it is worded as "it is recommended", though the example says "requires a") is that the straight distance helps with priming, which would potentially help the pump last longer or avoid priming failures. Once the pump is primed though, I don't see how the elbow being closer or farther could make that much difference, so I kind of doubt that explains your electricity use.

I'd bet the old pump was failing in a way (bad windings?) that effectively made it a lower HP (i.e. closer to .5hp of performance and power consumption), based on your description of the water flowing much faster with the new one.

And I suspect that you don't really need a 1hp pump -- my 22,000 gal pool has a 10-year-old 3/4hp pump currently and seems to filter just fine. I'm installing a VS pump tomorrow (and wrestling with the same issue on the straight pipe, as it won't fit if I do that without some extra U-turns), and plan to run it at even lower flow rate than the current pump. I hate to suggest buying another pump, but a 2-speed or VS might pay back if you could sell the almost-new 1HP pump on Ebay/Craigslist perhaps.

 

[addajio]

...might when restricted draw 800 watts (20% less) but only achieve 25gpm (50% less).

..."Point taken!"

And I suspect that you don't really need a 1hp pump

...I realized that immedeately

I hate to suggest buying another pump, but a 2-speed or VS might pay back if you could sell the almost-new 1HP pump on Ebay/Craigslist perhaps.[/QUOTE]

I hear ya. The Superflo's aren't expensive, so I might replace/downsize in 2 - 3 yr., and reduce runtime to 6 hr/day and monitor the electric bills.

thanks jmastron

Hey, if you decide to go without the inlet pipe, let me know if you get mega-suction, or increased bills. Actually, I'd appreciate comments from anyone
who has/will do the same!

 

[Isaac-1]

You might also consider replacing your motor with a 2 speed motor, and keeping this current motor as a spare.

 

[mgarf33]

The 90° elbows will not increase suction side flow.
Doubtful the 90°s will have much affect on the operation, but if you have a restriction:
It will increase head, increase motor RPMs, lower efficiency, lower water flow, and increase motor heat.

If you're getting high flow you likely fixed a problem like a bad pump.

 

[addajio]

Issac-1:
“You might also consider replacing your motor with a 2 speed motor, and keeping this current motor as a spare.”

Would that apply to a ¾ HP Motor? That would be my replacement.


Mgarf33:
“Doubtful the 90°s will have much affect on the operation, but if you have a restriction:
It will increase head, increase motor RPMs, lower efficiency, lower water flow,and increase motor heat.

If you're getting high flow you likely fixed a problem like a bad pump.”



Restriction sounds like a roll of the dice, I’ll pass.:colors:

You know, its possible that the HIGH suction/return pressure is a perception over-reaction on my part, having recently replaced Pump/Motor, but I’ve been maintaining this pool for 26 years, and have never considered it high before.
...on the other hand, I do turn 60 in July

 

[WardL]

Not sure I understand all of your diagnostics completely, but if the pump discharge pressure is higher, you are going to consume more electricity. The other thing you might consider is if there is any chance there is a blockage in the pump discharge line back to the pool. You might also compare the new pump capacity in GPM to the old pump. If the old pump was designed (at a certain discharge pressure) for 50 GPM and the new pump is designed (at another discharge pressure) for 100 GPM you would surely notice a big change. Of course, each pump will operate on it's pump curve meaning they will pump a specific GPM rate depending on the pump curve. It is possible your new pump will pump more water than your old pump even though it is rated at a lower HP.

 

[Isaac-1]

I am not sure I understand the 3/4 HP reference, everything you have listed shows a 1 HP pump. If you have a 1HP single speed motor, you can replace it with a 1 HP dual speed motor, on high it will run at 1 HP with whatever flow you now have, on low it will draw 1/4 as much power and flow about half as much water as on high.

 

[addajio]

WardL, It was an OLD Bronze Pump from the early 90s, and a used/rebuilt 2 HP Motor which was then rebuilt as needed. They more than payed for themselves and did the job. They are gone so I
can't compare, but I can see that the newer design accounts for both the higher flow, and thus, increased bill. I think I just became accustomed to a weaker flow/lower bill for many years and thought the higher bill was a flag of somekind. You brought to light yet another consideration [flow design] to explain the change - thanks

Issac-1, you suggested to consider a 1 HP 2-speedreplacement. I was asking in the case of buying a ¾ HP replacement, would a 2-speed then be necessary, as it willalready be a reduced flow. Actually, I don’t even know if ¾ HP motor is available in2-speed.









Issac-1, you suggested to consider a 2-speedreplacement. I was asking in the case of buying a ¾ HP replacement, would a 2-speed then be necessary, as it willalready be a reduced flow. Actually, I don’t know if ¾ HP motor is available in2-speed.