Do 2-speed pumps need controler to prime with Solar?

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WarmWater

WarmWater

0
Jan 11, 2012
8
Northridge, Southern CA
My 2hp 9 year old Pentair just gave out. I'm thinking of replacing with a 2-speed motor at 1.5hp. Here's my plan:

WINTER: Run the low speed the required time for turnover/cleaning and save $$ over what I WAS doing.

SUMMER & "shoulder season" April-October: When I get plenty of sun for my roof top solar panels to bring my water to low-mid 80's (and 90's in mid summer) I'll just switch the 2 speed to HIGH.

The few bucks I'll save in the winter time running my filter on low should make me happy. My original motor installer put in the 2hp wanting to see "water flowing" from the 3 return lines but I think 2hp is OVERKILL even with my added Solar on my 1-story house. I want to replace with a 1-1/2hp Pentair Wisperflow or Jandy or comparible 2 speed 220v.

QUESTION TO YOU: Do I need any sort of "controller"? Do these 2 speed pumps have a "low" and "high" switch ON THEM? or are they just lead connections in its j-box that I have to wire from a 2 speed controller?

Do 2 speed pumps have trouble starting in LOW speed? I planned on turning my Solar Off during the winter so the LOW speed pump doesn't ever have to push water 30' to my 5 10' panels on the roof. When I turn my solar controller on for "the Season", I'll switch the pump to HIGH speed all summer long.

Are there any issues with priming in low speed or priming in high speed with the solar on? Do I need a controller to ALWAYS prime in HIGH then automatically switch to low? Is there a possibility that LOW on a 2-speed could run my Solar heating to keep the water in panels longer to collect more heat or will LOW speed not override the pressure relief on the solar?

Again, I have no spa or water feature, just my pool filter and a Pentail lx220 (????) solor controller to the jandy-valve to divert to the roof when its warm enough and back when it's cooling. I'm hoping to just replace the motor with a 2 speed but as a DIY guy, the thought of a "controller" scares me but if you have any recommendations, I'm willing.
thx!
 
Sounds like a good plan and you have a lot of questions so I will try to answer them all.


Do I need any sort of "controller"? Do these 2 speed pumps have a "low" and "high" switch ON THEM? or are they just lead connections in its j-box that I have to wire from a 2 speed controller?
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Given your plan, you really don't need a controller. Some two speed pumps come with a mechanical switch but most don't so you need to check but adding a switch is really not that hard to do.


Do 2 speed pumps have trouble starting in LOW speed? I planned on turning my Solar Off during the winter so the LOW speed pump doesn't ever have to push water 30' to my 5 10' panels on the roof. When I turn my solar controller on for "the Season", I'll switch the pump to HIGH speed all summer long.
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Most of the older style two speed motors actually start on high speed anyways. There is centrifugal switch inside the motor that forces it to start on high and then it will automatically switch to low speed if that is how the external switch is powering the motor. Some of the newer two speeds, will start on low speed and stay there. Either way there are no worries about starting the pump on low speed.


Are there any issues with priming in low speed or priming in high speed with the solar on? Do I need a controller to ALWAYS prime in HIGH then automatically switch to low? Is there a possibility that LOW on a 2-speed could run my Solar heating to keep the water in panels longer to collect more heat or will LOW speed not override the pressure relief on the solar?
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By priming, I think you mean priming the pump. There are issues priming a pump on low speed as it will not always push all of the air out of the pump. However, a pump should not lose prime when it is off. This is usually the sign on an air leak. So after cleaning the pump, you may need to prime on high speed but after that, it should not lose prime. Also, putting a check valve after the filter will help the pump not to lose prime as well empty the filter.
 
Warmwater, I will be following this thread as I have been considering a 2 speed pump. I have a very similar set up but I have not invested in a 2 speed pump yet because I was afraid that it would not work for me and I would be out some money. I have not seen anyone on this forum who has a 2 speed pump and starts their solar in low speed, the solar panels mounted on a one story house. It would be nice to see comments on people who have similar set ups. Please keep us informed if you do purchase a 2-speed. Maybe you can be the Guinea pig. :-D :-D :cheers:
 
brentr,

If you read Warmwater's thread again, he is not suggesting to start solar in low speed but to start the pump in low speed when solar is off. He is planning to run solar on high speed and use low speed for when solar is not running. That is not a problem. However, priming solar on low speed can be problematic if the flow rate is not sufficient to purge the panels of air and the pressure not sufficient to keep the vacuum release valve closed.
 
I have a 2-speed pump and my solar panels are on a single story house. I don't have any problems with my system starting up with the pump running on low speed. I can leave it on low speed all day or flip the switch for high speed when I want to run the solar more efficiently. You can see my specs in my signature.
 
There is a big difference in priming power between a 2.5 HP pump that you have and a 1.5 HP pump the OP has. A 2.5 HP pump can prime a set of panels on a single story roof because the flow rate even on low speed is fairly high plus they tend to have a much higher head curve for vertical lift than a 1.5 HP pump would.
 
Pardon my slightly OT although related question. In my other thread, Mark thought I could get away with a 3/4 HP 2-speed with 10-11 solar panels (although running on high for the solar), but that seem pretty small compared to ping's 2.5 HP pump. Is the need for that large of a pump primarily due to them having a spa unlike myself?
 
jblauert said:
Pardon my slightly OT although related question. In my other thread, Mark thought I could get away with a 3/4 HP 2-speed with 10-11 solar panels (although running on high for the solar), but that seem pretty small compared to ping's 2.5 HP pump. Is the need for that large of a pump primarily due to them having a spa unlike myself?
Click to expand...

The spa is the reason for having the 2.5 HP pump.
 
Thanks for all the great info guys. I'm happy to be your Guinea Pig Brentr! :-D BUT I've now changed my mind on the 2 speed. I'm going to buy a Variable Speed tomorrow. I've read lots about the Pentair Intelliflo's and issues with solar, so here is my findings regarding Pentair Variable Speeds AND having a Solar Heat component to my pool. There are 4 models so I've listed the differences and their model numbers ():

Intelliflow VF (11012): the VF means it has the flow sensor to increase RPM when flow changes (Terrilble on solar with diverter valves opening and closing when clouds come in and out, then the system shuts down). NO Good.
Inteliflow VS 3050 (11013) requires a controller that I don't need or have (no spa connected to my pool) NO Good.
Inteliflow VS+SVRS (11017) The SVRS plays havoc with the pressure change from solar diverter valves and shuts it off and I don't have any safety concerns on the intake openings hurting anyone anyway. NO Good.

THE ONE TO BUY FOR ME: Inteliflow Variable Speed (11018): Just a plain, vanilla variable speed with no controller or other safety features that might misread a flow or pressure change on the solar. It's $1000 and my power company is giving a $500 rebate now. A good 2-speed Pentair is just under $400 so in the end I'm paying maybe a $200 premium but I get to lower the motor RPM's in winter months to a few hundred watts per day instead of 10,600 watts per day (thats 11 amp motor x 240volts x 4 hrs = 10,600w). In the summer months I'll just 'up' the RPMS knowing my solar will kick in all day. I'll have to play around with the "shoulder" months; see how low I can go with RPM's and keep the vacuum release valve on the solar operating and pick up lost BTU's due to my previously too-high flow rate zipping water thru the roof panels.

I contacted Pentair Tech Support this morning and he was confident of my plan for the 11018. I'll probably start a new thread for my up-coming experience with this model and my solar heater so others can avoid my mistakes or benefit from variable speed.

Thanks everyone!
 

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With a rebate like that, a variable is a great choice with solar and it takes all the guess work out of pump sizing. You can dial in the RPMs high enough to keep solar happy and low enough to keep your wallet happy. :wink:
 
Even living in CA, I still don't get that kind of rebate. Our power company only rebates a $100 which doesn't make it worth it.
 
Warm Water: good choice, The intelliflow will treat you well.
Much better than a 2 speed on every level.
The difference between an induction motor and a permanent magnet motor is substantial!
You should easily see a 50-70% decrease in cost of pump operation.

But, to answer your original question, you do not need a "controller" so much as a 2 speed timer,
like Intermatic's T106.
2 Speeds have two different power inputs for high and low speed, and if you were to ever put power to both speeds (windings) simultaneously, motor damage would occur. That's why you need a compatible mechanical timer.

Intelliflows (but also, IntelliPros, EcoStars, and VS-FloPros, as they are very similar in many respects) are the answer to the high power bill that goes with a 1.5-2.5 Hp motor running all day. In Fl, if you were running a 2Hp all day, you should save $30-35/month on the power bill (at ~ $0.12/kWh) Payoff is short, and I cant stress enough how much better these variable speed motors are!

But, again, good choice!
-B.
 
Well, to clarify:
Yes, it is probably possible to save 50% with use of a 2 speed.
get it down to exactly 1 turnover per day, and only run it on low speed.
(assuming you are starting with 2Hp and running it 10 hrs/day)

But, the OP mentioned he wanted to use the solar during the useful part of the day (3-5 hrs).
That's going to mean he'll turn a good percentage of the pool during the solar time, at high speed, which is even slightly less efficient than a single speed pump at the same HP (because it has to drag an extra long rotor). 2 Speed motors are efficient on low speed, but can do real work on high speed. Therefore, you need to minimize high speed to maximize efficiency.

At the end of the day, the point I was trying to make is that Permanent Magnet motors are vastly more efficient than induction motors.
A regular two speed 1.5hp say Ao smith motor, will run about 50% efficient at high speed, and ~30% efficient on low speed.
As a contrast to that, the motor from (any Variable speed pool pump) should be running about 90-92% efficient.

Induction motors generate a great deal of heat, which is all just wasted electricity.
The intelliflow runs lukewarm to the touch, as compared to 140F.

This is a quantum leap in motor design for the pool industry.
I wanted to illuminate the difference between PMSM motors and Induction motors. It's huge!

But, Mas, you are absolutely right, under some circumstances you can save decent money with a 2 speed. I usually recommend them for pools without any water features (pool cleaner, solar, fountains)

-B.
 
Well, let's clarify your statements as well.

JettaGLi16v said:
Well, to clarify:
Yes, it is probably possible to save 50% with use of a 2 speed.
get it down to exactly 1 turnover per day, and only run it on low speed.
(assuming you are starting with 2Hp and running it 10 hrs/day)
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You can still save 50% on low speed with any number turnovers, it just needs to be a fair comparison. If the single speed pump is running for two turnovers and the two speed pump is running for two turnovers on low speed, the two speed will still save over 50%. You don't need to compare it to a 2 HP pump either. A 3/4 HP on low speed will save over 50% than the same pump on high speed.

Also, you need to run a variable on lower speeds as well to get the savings.


But, the OP mentioned he wanted to use the solar during the useful part of the day (3-5 hrs).
That's going to mean he'll turn a good percentage of the pool during the solar time, at high speed, which is even slightly less efficient than a single speed pump at the same HP (because it has to drag an extra long rotor).
Click to expand...
The motor dimensions of a two speed motor is no different than a single speed motor so the rotor length is exactly the same so I am not sure what you mean by that. If you mean the rotor design is different, that is not true for all two speed motors. It depends on the design and if the stator windings are 4 pole or a consequential pole motor is used. In some cases the two speed motor is slightly less efficient than the single speed counterpart but that is not true in all cases.


2 Speed motors are efficient on low speed, but can do real work on high speed. Therefore, you need to minimize high speed to maximize efficiency
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This is a true satement for a variable speed as well. The VS will need to run at higher speeds for solar and will not be as efficient as running at lower speeds so the same rules apply. However, as I mentioned before, the VS can be optimized to run at just enough flow rate to keep the solar happy. With a two speed, that optimation has to occur when choosing the pump.



At the end of the day, the point I was trying to make is that Permanent Magnet motors are vastly more efficient than induction motors.
A regular two speed 1.5hp say Ao smith motor, will run about 50% efficient at high speed, and ~30% efficient on low speed.
As a contrast to that, the motor from (any Variable speed pool pump) should be running about 90-92% efficient.
Click to expand...
I would not say vastly more efficient and not in all cases. The Whisperflo line of motors is far more efficient than than 50%. Specifically the 1.5 HP full rated motor has an efficiency of 77.4%. Yes it is lower than the Intelliflo but it is not 50%.

There are also some disadvantages of a PM motor. For one the magnet acts like a heat sink and retains a lot more heat than a wound rotor. So although the motor is more efficient and will not generate as much heat in stator, it can actually retain more heat in the rotor. This is why some VS manufactures have gone to an induction motor with a VS drive.

Induction motors generate a great deal of heat, which is all just wasted electricity.
The intelliflow runs lukewarm to the touch, as compared to 140F.

This is a quantum leap in motor design for the pool industry.
I wanted to illuminate the difference between PMSM motors and Induction motors. It's huge!
Click to expand...

It is not as big a difference as you think it is especially if you consider the lifetime costs of the two types of pumps. In most of the US, the energy costs are on average about $0.11/kwh so it can take a long time before the Intelliflo can make up the costs difference with a two speed pump even though the wire to water efficiency might be twice as much on low speed. It does not always have the lowest lifetime costs. The up front cost of the pump and controller can make it more cost efficient to go with a two speed. In this case, the OP gets a large rebate so it is a no brainer to go with a VS but it is not always the case.
 
It's almost 1 year since I originated this posting about purchasing the variable speed pump. I DID, and I got the Pentair Variable Speed 11018 (the one that does NOT have the flow sensor/regulator/safety thing) It works flawlessly. It was very easy to program it high rpm enough to pump up to my metal solar panels on the roof and keep my Kreepy Krawly moving just fine. It kept my pool just as clean and warm as it's ever been. Now that I stopped swimming & solar heating it, I've re-set it to the timer that comes on a low wattage/rpm for 4 hours/day and I "hit" the "clean" timer button on every other week or so that ramps up rpm for a quick and thorough 2 hour touch up. I'm hoping now is when I'll be saving $$ on power bills. And it is so quiet, I have to stare at the motors basket to see water flowing thru it sometimes.
 

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