Does a variable or multi-speed pump make sense with a heat pump?

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twesterd

twesterd

0
Aug 15, 2014
30
Pflugerville/Texas
My pool pump just died and now I need to figure out the right replacement hoping to improve energy efficiency. It was an old 1.5HP A.O Smith single speed motor with a Challenger 2HP self-priming wet end. The pump feeds (1) the pool filter, a Purex Triton FNS Plus 48 DE filter, (2) the pool cleaner, a Polaris 360 pressure side cleaner, and (3) a RayPak R8350TI-HC reversible heat pump.

My main issue is that the heat pump requires 30-60 GPM water flow for the heating function to turn on (it uses a flow sensor), so the low speeds of these variable pumps seem to be too low (12-23 GPM). Additionally, a heat pump heats slowly, so it needs to have the water running for a long time to do its work. Ideally, the pump runs for 4-6 hours each day at high speed to clean and heat the pool, then it could slow down below 30 GPM just to filter more, but it doesn't seem necessary as the water stays very clean. Does it just make sense to try and use a pump that would produce around 35-40GPM and leave it at that? I believe the previous 1.5HP motor was overkill for the pool (the outlets have substantial pressure while the pool cleaner runs and I have to open the pool cleaner valve inside the pool quite a bit to slow the cleaner down).

NOTE: My pool is odd-shaped/curvy, is not deep (about 5 feet at the deep and and 3 at the shallow end, and is somewhere around 11,000-13,000 gallons. I live in Pflugerville, Texas where the summer months heat the pool just fine and I use the heat pump to cool the water in summer and extend my season as long as possible into winter. I use a pool cover that dramatically helps keep heat and water inside the pool. The pump is about 10-15 feet from the pool and there are three directed outlets for the pool itself.

Any suggestions?
 
It depends on your electrical rates, and what percentage of the year you are using the heat pump. In Texas, I suspect your electrical rates aren't all that high (below $0.15?), in which case a two speed motor selected so high speed is 35 to 40 GPM would be ideal. You could only use it on low speed when not using the heat pump or pool cleaner, but even that is likely to pay the small additional cost for getting a two speed.
 
I do have reasonably low rates in Texas, but two speed pumps also add the cost of a controller for them to work correctly with my heat pump. I suspect my previous pump was significantly over-sized and I might be better off with a single speed 3/4HP versus 1.5HP motor. Some of the newer models seems to provide greater flow using less HP. Because of my heat pump, I don't think I would really get much use for the low speed option without adding significant upfront cost. Low speed could only be used for a few months in summer.
 
Don't get a controller, just switch the speed manually. You only turn it on low when you know you won't be using the heat pump. Even if that is only two months a year, it will pay the extra for a two speed motor/pump.
 
Well, I'm not finding any dual speed pumps that offer great flow (I.e a Hayward Super II) that are in my budget. I really want to keep the price below $400 as there are just too many cash-eating items that love my money right now. Do you have any examples of what you would suggest? During summer I need about 2 hours of run time per day for cleaning/filtering. The pump I am looking at will draw about 7.1-7.5 amps.

NOTE: I am also considering a single-speed WhisperFlo as it appears I would get the flow I need at 3/4 HP, but the price is a lot higher.
 
Nearly any pump will give you 30-60 GPM or are you trying to size low speed at 30-60 GPM? Why do you say there are no pumps that "offer good flow"?

BTW, low speed is not half the HP of high speed, it is half the flow rate. So if you can find a pump that produces >60 GPM at high speed, which most should, then it should produce more than 30 GPM at low speed.

The 1 HP SuperFlo, would deliver about 66 GPM on high speed on typical 2" plumbing which means it would produce 33 GPM on low speed.

BTW, you could just replace the motor on your current pump with a two speed. That should be well below $400.
 
Thank you for your feedback.
(1) My old "pump" or wet end is very old (installed in 1994), and needing too much care. So, its time for a new wet end too.
(2) I am not sure of my "total head in feet" and that makes selecting a pump more difficult. I don't think its much as my pump sits about 10-15 feet from the skimmer and 15-20 feet from the drain at the bottom of the pool's deep end (pump is close to deep end). When I look closely at various pumps, many appear significantly better at maintaining flow at lower speeds and with higher "total head in feet" values. Let's say bends and vertical feet distance make the average "total head in feet" distance 30-35 feet... when I look at the pump charts, many fall well below 30 GPM, others seem to stay above 30 GPM. Below 30GPM my heat pump turns off.
(3) I don't think my pump needs to produce any more flow than is necessary to run the pump. I believe my Polaris cleaner will work just fine at lower speeds. The only exception is when the cover is off (debris/leaves can get on the water's surface)... higher flow does make a big difference physically causing my water to circulate and drive floating debris straight to the skimmer.
(4) I am just now looking and learning as my now defunct pump forces me to learn fast.

I have found a Pentair SuperFlo VS for $575 and this pump is now getting my attention as I can adjust the RPM and length at time for three levels of operation (high, medium low), and , if I understand, in 250RPM increments. This intrigues me because I can set the lowest RPM that lets my heat pump function, I can set a value for a higher speed, if ever necessary (like circulating the surface water), and can set a low speed purely for filtering. The lowest price for a single-speed pump that I like is $375. The extra $200 does seem worth it.

Any experience/feedback from anyone with this pump or any alternatives recommended?
 
Why do that when you can get the SuperFlo VS for only a few hundred more?

Adding a VS motor will cost as much as the entire pump.
 
You are right, but I am very tight on money this month and I need to get a new pump in now. Knowing that, this is why:

(1) I don't like the wet end as much on the lower-priced VS models, (2) I need to run it it at close to hi-speed for 4-6 hours/day anyway (for months) to keep my pool at the 88 degrees I love, and (3) I like this VS motor better and think I'm paying close to the same price for what I get in the end anyway. Look at its options including the controler and how its a true permanent magnet motor: http://www.poolsupplyunlimited.com/ecotech-ez-programmable-variable-speed-motor-and-control/145468p1
 

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The wet end is more efficient on the lower end VSs so why don't you like them?

All the Pentair and Hayward VSs are also PM plus there are a lot of hours or run time and reliability is well known. Those add on VS motor have not really had much field time so I would be concerned about reliability. It wouldn't be the direction that I would go in.

Given your location and heat requirements, I doubt you would benefit much from a VS so why not go the two speed route?
 
Okay, after much searching and investigating... yada... yada... I decided to rebuild my existing wet end: Challenger 2HP (horse power)/ HP (high pressure) version. The pump itself has great output and I didn't realize just how good until I compared flow charts It doesn't leak, does look very sun-faded, but was also very quiet. All the noise was the old motor. I decided to buy the EcoTech VS motor to go with it (http://www.poolsupplyunlimited.com/ecotech-ez-programmable-variable-speed-motor-and-control/145468p1). I just can't beat the price and potential savings. Previous versions of the motor did have a recall for faulty grounding around the cover that could be a shock hazard, but that issue was fixed in this model. I spoke with the sales staff who stated they haven't had any returns or dissatisfied customers on the unit with many sold. Total cost for the motor, shipping, rebuild kit and new impeller was under $600. I believe I can tune the motor for the best speed and time for both winter and summer seasons and I should have a reduced electric bill.

I thank all of your or your feedback. I will post an update after get the install completed.
 
I really don't understand your logic. Why would you pay more for something that is going to be less efficient and less reliable than the SuperFlo VS? It just doesn't make any sense.
 
First, I meant to say it was less than $500, not $600 and I like the EchoTech VS more as its a permanent magnet motor with better control options. The Challenger is very quiet... I like that too. I also don't have to cut into the plumbing as the rebuild can be done without removing it from the plumbing.

CRITICAL: The Superflo VS warranty changed: they only warranty for 60 days on self-installed pumps... a deal breaker.
 
Most of the VSs (SuperFLo, MaxFlo, Intelliflo, EcoStar) use PM motors too so that is not unique. Plus all VS pumps are very quiet so that should not be a deciding factor either. The Hayward MaxFlo has a 1 year warranty for self installs but most of these pumps will either fail within 60 days or after several years so I don't think that would be an issue either.

The plumbing part I get and is a good reason but I would still be a little cautious of that motor.
 
You can just replace the pump motor with an ecotech ez pump, you can find them for like 380 dollars, thats what I would use if I had to swap it out, for your use, you could probably use the smaller version and I think its even cheaper. 2 speed is a pain because you have to wire in more stuff.
 
That's what I bought, the EcoTech 1.5 HP VS motor: it was $375. I also bought a new impeller, and tune-up kit for the Challenger wet end. I am positive that the pump can be run at substantially fewer RPMs than the original 1-1/2 HP pump to get the flow I need. I use my pool year round, and $$$ savings for usage was not my primary driver: quiet was most important to me. I don't need nearly as high flow during summer as the its only the Heat Pump that requires the most flow for long periods. I wanted to stick around $400 for multiple reasons, adding $100 got me what I think is a good option for limited initial cost dollars.

FYI: I am cautious/weary of the motor too but did get positive feedback about it and thought it was worth the risk. It takes people like me to get feedback. A fixed two speed doesn't make sense to me. A single-speed doesn't make sense to me. By looking at the video link I provided in the earlier post. If you listen at the end, the motor is very quiet. I suspect I will get the flow I need at 60% or less since I had far too much flow on the old motor. My pool is small, the pump is close to the pool. I need enough flow for a pool cleaner, three jets, one skimmer, and the heat pump during non-summer months.
 
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Okay,I said I would provide an update and today I successfully installed the EcoTech EZ 1.5 HP VS pump and... WOW... am I happy! The Challenger pump makes zero noise and the EcoTech motor its extremely quiet. Even at 100%, it makes very little noise. My Heat pump, which is quiet, makes more noise. When running the pump at 60% or less I don't hear it all all. It took me about 10 minutes to get used to adjusting the menu and I'm sure it will actually take me a few weeks of experimenting, but it looks like I won't ever need more than 85% for a couple of hours to ensure the pool cleaner can get its job done. The heater still runs well below 40% power which means I am getting the minimum 30 gpm required for the heat pump to turn on. So, this is perfect for me.

I connected the power to the mechanical timer, turned it on and removed the plastic pieces that turn the timer off. The EcoTech motor now turns itself on and off according to the schedule and percent power I set. The heat pump auto turns and and off based on water flow and/or the actual pool temperature (if the water reaches temp, it auto turns off and auto turns on when too low). Obviously, the other main factor is how long the motor lasts and only time will tell. Right now, I am very happy. The old A.O. Smith 1.5 HP motor was DRAMATICALLY louder. I have no worries about my neighbors hearing my pump anymore.
 

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