Another Pump Replacement question

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G

gkran

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Feb 20, 2008
29
My main Hayword single speed pump motor (maybe 10-20 years old) is screaming, and I am costing out the repair. I am wondering about the trade-offs between replacing the motor or the whole pump.

Stats:
- Pool is 15 to 20 years old, in ground, gunnite, ~ 12000 gals.
- DE filter, probably original with the pool
- Have Salt system, and Kreepy Krauly cleaner (has its own suction connection to the main pump)
- Spa cascades into the pool, jets have a separate booster pump
- Repairman thinks the motor could be 3 hp. This is probably based on the fact that it is larger than the spa booster pump which is 2 hp. (most of the markings are worn off and it is hard to get back by the motor)
- We are in So Cal, so the pool never closes, and the marginal electricity rates are 0.31+ cents per kWh
- I would like to decrease my electric bill
- We plan on being in the house at least 5 more years, so that is the upper limit on break even time

Is it cost effective to replace the whole pump and not just the motor?
What about multi-speed vs single speed?

I am doing some research, so if anyone has data, advice, or can point me to some resources, I would appreciate it.
 
There is pump efficiency data in my signature if you are interested in a energy use comparison. Break even is somewhat hard to figure out since there are a lot of variables but it can be done.

If the wet end of the pump is still in good condition, the cheapest solution is to replace the motor with a two speed motor and you can also downsize the impeller at the same time (assuming they still make them).

The next cheapest solution is to replace the entire pump with a two speed pump of lower HP. Energy use would probably be similar to replacing the motor and impeller but up front cost is more expensive.

Finally, the most expensive solution up front is a variable speed pump but it will likely save you the most money over the life of the pump. 5 years is a bit short but given your rates and the fact that they will only increase in the future, I would hazard to guess that a VS pump will still probably come out ahead. The bonus is that the VS pump is the most flexible of all and allows you to fine tune flow rates and energy use for many different situations. Also, there are many more to choose from than there use to be.
 
It looks like going to a VS will cost an additional $800 + $1500 for a new controller (unless I can add modules to my current Pentair controller to support VS). The Electric company's brochures estimate a $350 annual savings for VS.

We think the motor may be oversized, and he is going to recalculate the pump needs. If I do have a 3 hp and can replace with a 2 hp, that would lower my electric bill without the extra investment.

I am worried with downsizing the pump. How much guestimation goes into calculating the size required? Are there any other special conditions that need to be taken into account? I will be doing some research tonight...
 
Any idea what size the filter is?

I could see a 2 - 3 HP motor if you didn't have the booster pump to drive the spa action. A 1 - 1.5 HP would probably be sufficient to run the pool and spillover.

I will gladly defer to Mark on these issues, but that's my best guess on your situation :-D
 
Is there a reason they put such a large pump on the pool to begin with? A spillover shouldn't need much unless it is really wide. Are there any other waterfalls, water features, in-ground cleaning system, etc that may require higher flow rates? Either way I would still consider a two speed or variable speed pump.
 
I don't know the history of the pool design.
There is a waterfall, but it has two pumps of its own that are totally independent.

There are two small spillovers from the spa to the pool, each is probably 12 - 18 inches wide.
The Kreepy suction side cleaner.
The filter is a Hayward DE 6000 (60 sq ft filter area)
Salt System

The equipment is probably a 40 ft run from the pool and maybe elevated 5 ft.
 
Title 20 law says that you can not replace the motor, you have to install a 1/2 hp single speed or variable speed pump. With a $300 Edison rebate ($200 to homeowner and $100 to the contractor), currently a Hayward variable speed pump cost the least. We sell them for $1100 less $300 rebate installed. Any variable speed pump will work on your pool. I do not think you have a 3 hp now, most likely it is a 2 hp. If you are running the old 2 hp pump 4 hours a day you will save $500 a year in electricity. 2 speed pumps cost $1200 and save only $250 a year so do not get a 2 speed! 1/2 hp is to0 small for your pool. A variable speed pump is by far the best choice and they have may other advantages (filter better and are adjustable etc.)

Ben
www.poolsbyben.com
 
From Title 20 page 234.

(5) Residential Pool Pumps.
(A) Motor Efficiency. Pool pump motors manufactured on or after January 1, 2006
may not be split-phase or capacitor start - induction run type.
(B) Two-Speed Capability.
(i) Pump Motors. Pool pump motors with a capacity of 1 HP or more which are
manufactured on or after January 1, 2008, shall have the capability of operating at two or more
speeds with a low speed having a rotation rate that is no more than one-half of the motor's
maximum rotation rate.
(ii) Pump Controls. Pool pump motor controls manufactured on or after January 1,
2008 shall have the capability of operating the pool pump at at least two speeds. The default
circulation speed shall be the lowest speed, with a high speed override capability being for a
temporary period not to exceed one normal cycle.
Click to expand...

So single speed up to 3/4 HP is allowed. However, I can't seem to find where it mentions that you cannot just replace the motor.
 
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