Pumps, volts, hp, no use - totally lost want new pump?

[pmcd]

I have become totally confused when it comes to replacing our old 1.25 HP 110v pump. We have an 8,000 gallon semi-in ground pool which is 4' deep ( water is at that constant depth), and is 12.5'x21.5' in dimension. There is a salt generator and a solar system with panels on a flat roof around 10' high and 20 or 30 feet or so from the pump. There is an electrical conduit running to the pump area which supplies electricity to 4 110v outlets (GFI protected). No pool house, pump and sand filter are hiding in bushes along with a Goldline automation box and a Zodiac salt generator.

Want:
- 110v 2 speed pump which is quiet, preferably with an electrical cord that I would just plug in to a 3 prong outlet. The confusion arises as I keep seeing 220v pumps when you go to 2-speed or variable speed pumps. The pump is below the water so an inground pool pump could be used if necessary, but I really don't want 220v.
- what HP could I get away with? 1?

We live in Toronto, Canada but we travel to the USA a lot so we could get the pump there, if required. It seems that the moment I mention two speed pumps up here the dealers keep talking 220v.

Hayward, Pentair, etc... would be fine. Do the multi-speed pumps have to be inside a shed or can they live outside since I assume they have more electronics that can break?

I have seen some interesting claims about something called an EcoPump. Almost sounds unbelievable. Does anyone know anything about it?

The main aim here is not saving money but rather getting a quiet pump. Of course saving money would also be nice. We run the pump 8-10 hours a day and electricity is around 11 cents/kwh.

Sorry for the unfocused post. I never thought pumps could be this complicated.

Philip


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[Isaac-1]

I know Waterways makes a 2 speed above ground 120V pump, but don't know any details beyond that.

 

[mas985]

A few 120v choices:

In Ground

Superflo SF-N2-3/4A - Hard to find
SuperMax N2-3/4A-HP - Hard to find


Above Ground - Since the pump is below water level, it is ok to use these.

Dynamo 1 HP DYNII-N2 1 HP - Self priming so much like a IG
Dynamo 1.5 HP DYNII-N2-1-1/2HP - Identical to above pump (ignore labels) but comes with a cord.
Optiflo 1 HP 347990 - Comes with a cord.

All of these are about the same size and will deliver ~50 GPM and should have enough priming flow for the solar panels. Sounds like the pool is really a AG pool so I would go with one of those as they are cheaper and have the cords you are looking for. BTW, what was your old pump make/model#?

 

[pmcd]

I was looking at the pump and I couldn't even find the HP. I believe the make is Dynamo and it was installed 8 years ago. Maybe even a 1HP? The 2 Waterway pumps seem like they would work just fine. They have a 1HP and a 1.5HP. I'd prefer the 1HP but am a bit nervous that it couldn't handle the solar. The 1.5 might be overkill and louder. I want the pump to be as quiet as possible. Does a 1 HP 2-speed pump act as a 1/2 HP pump at the lower setting?

The Waterway pump comes with a 3' power cord which is too short to reach our current GFCI plug. It's 4 feet away. Are these cords easily replaceable by say a 6' one?
I don't really want to use an extension cord, which may even be dangerous.

The solar panels are the one unknown in sizing the pump. I am getting various opinions depending on the person I talk to. One solar installer said that a 1HP pump would be more than fine, another said you want more. Sigh.

I'll look into those other models as well. I noticed that Hayward in the USA makes a 2-speed 1HP pump but that same pump up here seems to be 230v only.

Philip

 

[Isaac-1]

How many solar panels do you have and what size are they?

 

[Bama Rambler]

Can you find the amp draw on the data plate of the motor?

Most any 1 hp pump will handle the solar, even the above ground ones.

The 3ft cord is an NEC requirement. If a permanently installed pump has a cord & plug it can't be longer than 3'. However the cord is easy to change.

 

[mas985]

They have a 1HP and a 1.5HP. I'd prefer the 1HP but am a bit nervous that it couldn't handle the solar. The 1.5 might be overkill and louder. I want the pump to be as quiet as possible.

You need to be very careful judging a pump by just the HP rating, especially AG pumps. The true power of an AG pump is much lower than what a label HP will indicate. As I pointed out in my previous post the 1.5 HP Dynamo (SPL rated) is IDENTICAL to the 1 HP Dynamo which is an up rated pump. They have identical parts (impeller, wet end, and motor). The only difference is the label so don't be fooled.

Next most pumps make about the same noise when they are new and at full speed. Usually, the reason a pump becomes noisy is the bearings start to fail. Also, when running on low speed, nearly all pumps are very quite because the flow rate decreases.

As for solar, the Dynamo has a max head of over 50' so a 10' rise for solar is no problem. There will be plenty of flow for solar priming.

Does a 1 HP 2-speed pump act as a 1/2 HP pump at the lower setting?

Not even close. A 1 HP 2 Speed on low speed is the "equivalent HP" of 1/8th.

When it comes to sizing pumps, the ONLY thing that maters is the head curve. The following chart shows a number of smaller pumps and their performance on two different plumbing system. Curve A is closest to an AG 1.5" plumbing system. Note that the Dynamo 1 HP and Dynamo 1.5 HP have exactly the same performance (identical pumps) and they are actually smaller than a 1/2 HP Whisperflo & Tristar IG pumps. So again, be very very careful when comparing pumps and ignore the label HP, it is a very poor predictor of performance.

 

[pmcd]

Thanks for all the information. I finally found out the pump I currently have: it is a

Dynamo Pump DYNII-N1-1. The part number is 340171 but that is an old model so I couldn't find the exact part # on the Pentair site. In any case it is a 1 HP pump I assume. It is also unbearably loud to the point where I worry about the neighbours complaining.

The solar panels cover 157 sq.ft. .

I am still confused about the 2-speed issue. If the pump works at the lower speed (1750 or so) then would that handle the solar panels? The higher speed is roughly 3500.

There are 115v in-ground pool pumps that are two speed. Would these distribute water better? Hayward seems to have some.

Bit disconcerting that most pool pumps have a similar noise output.

Philip

 

[mas985]

High speed is around 3450 RPM, low speed is around 1725 RPM and half the flow rate of high speed. However, most people will run solar on high speed because it is more efficient (higher heat transfer) and it is not easy to get a solar system to work properly on low speed. The vacuum release valve would need to be placed a few feet above the pump and you will need a controller that can prime the panels on high speed and then switch to low speed for normal operation. A two speed timer could be setup this way but most automation systems including solar controllers cannot.

There are 115v in-ground pool pumps that are two speed. Would these distribute water better? Hayward seems to have some.

I posted a couple Pentair IG pumps earlier too but depending on the pump, they might have higher flow rates and cost more to operate. But the only difference between an IG pump and AG pump is an IG pump is self priming while an AG pump is not. Keep in mind the Dynamo IS a self priming pump which technically makes it an IG pump but it is normally sold as an AG pump. Another example of label confusion.

Bit disconcerting that most pool pumps have a similar noise output.

Yes but a new pump will probably be quieter than your old pump even if it is exactly the same pump. As pump's age the bearings get older and start to wear out so they start making more noise.

 

[pmcd]

As for solar, the Dynamo has a max head of over 50' so a 10' rise for solar is no problem. There will be plenty of flow for solar priming.


When it comes to sizing pumps, the ONLY thing that maters is the head curve. The following chart shows a number of smaller pumps and their performance on two different plumbing system. Curve A is closest to an AG 1.5" plumbing system. Note that the Dynamo 1 HP and Dynamo 1.5 HP have exactly the same performance (identical pumps) and they are actually smaller than a 1/2 HP Whisperflo & Tristar IG pumps. So again, be very very careful when comparing pumps and ignore the label HP, it is a very poor predictor of performance.

This is a really fascinating chart although I am having trouble reading it since the vertical axis seems to have both the GPM and " average feet of head".

For 8000 gallons you'd only need [8000/8]/60 which is less than 20 GPM to turn over all the water every 8 hours. Now comes the confusing head thing. The place where water comes in and out of the pool is 22 feet away from the end of the pool. So without the solar that would be 22' of head? With the solar, the water first travels say 20' to the house, 10' up to the roof, 15' ( that's a guess) through the solar panels and then heads back to the pool. Does this mean I have to add 20+10+15
which is 45 to the "head" calculation making the real head 67'? The reason I am asking is that I would like the option of adding even more solar panels ( probably of a different type) which would increase the distance the water travels through the panels.

I guess the question is how do you factor in the solar system into the "average head" calculation?

The 220v pumps would have an advantage of requiring fewer amps but then 220volts is something I worry about at the pump from a safety point of view. Would these pumps, such as the variable speed pumps, have to be kept in a shed to protect them from the elements, as oped to AG pumps which seem to be happy outside?

Philip

 

[mas985]

So for the chart, the colored bars represent GPM on the left axis. The black symbols represent the head loss for the corresponding flow rates on the right axis (see legend on bottom). Only two points on the head curve are shown for each pump.

Next, I would ignore turnover. It really isn't important. To determine pump run time, read this: pool-school/pump_run_time

Next, head loss is proportional to the length of pipe but it does not equal the length of pipe. It is much more complicated than that and involves calculation of the individual head loss components of pipe, fittings and other pieces of equipment. Also, head loss is not a constant, it depends on the flow rate through the plumbing. So basically a pump has a head curve and the pluming has it's own head curve. Where the two curves intersect is the operating point. This calculation can be done but it is somewhat involved. I have a few tools in the spreadsheets link in my sig that can help you measure the head loss in an existing plumbing system.

I guess the question is how do you factor in the solar system into the "average head" calculation?

Why does it matter? If the panels are plumbed in parallel, there will be a reduction of head loss so flow rates will increase but not by much. However, the addition of panels usually requires a little more flow rate to hit the 0.1 GPM/sqft target. But I don't think you will need to change anything.

The 220v pumps would have an advantage of requiring fewer amps but then 220volts is something I worry about at the pump from a safety point of view.

110v can be just as deadly. That is why you bond a pump and put it on a GFCI to remove the risk. But really there is not much of an advantage to 220v. The motor power draw is the same either way and the motor efficiency is the same. The only difference is the current in the wire feeding the motor.

Would these pumps, such as the variable speed pumps, have to be kept in a shed to protect them from the elements, as oped to AG pumps which seem to be happy outside?

I think quite a few people have their VS pumps installed outdoors so it isn't total necessary to protect them although it might be a good idea to use a surge protector since they do have electronics on board.

 

[scooperhsd]

There really isn't much to choose on running a given pump on 120 vs 240V - power is power, after all. The big advantage for 240V operation is that doubling the volts halves the amps, so for a given length of wire, the wire guage for the 240V can be smaller without overheating / or other adverse effects.

The other factor to consider - ideally, you should have GFCI protection to your pump (and anything else electrical close to your pool). Most people are familar with what this means on 120V - single pole GFCI breaker, GFCI outlet, etc. As far as I know - what you have for 240V GFCI is a double pole GFCI breaker, which is probably a premium price over the single pole counter part.

 

[pmcd]

Just a few clarifications:

1- If you hold a 220v source between two fingers the resistance in your body is fairly small and you will get a large current with a very large power surge going through you, twice that of 110v. That is why I am a bit nervous about 220v. I could be mistaken somewhere about this but one does tend to stay away from high voltage situations!

2- Right now I plug the pump into a GFCI outlet. With a 220v pump would I have to have a GFCI outlet with different plugs and then plug the pump into one of those outlets? Or would the pump have to have its own wire running to the fuse box? Our stove is on a 220v line and the plug seems rather large. I would get an electrician to do this but I am trying to get a feeling for what things would end of looking like. Europe uses 220v I think and their plugs seem to be fairly small. Is that the kind of outlet we are talking about?

3- In Toronto the electrical rate is around 12 cents/kwh during the day when the sun is out and the pump runs. It then drops in half around 5pm. One reason for a low rpm pump was that it would be quiet and make solar heating make more financial sense. As it is, natural gas is cheap so that solar ends up making less sense. I realize there are other issues but wouldn't something like a 1HP Hayward Super pump VS, which is overkill for us, be able to push water up to the roof at 1500rpm or perhaps 2100rpm? I was going to add more panels to the system on another flat roof we have which is 8 feet higher than the first flat roof. We also have a flat roof outside "shed" which is only 6' above the pool pump. The point here is to not get a pump which ends up boxing me in should I decide to expand the solar system.

The whole point of this exercise is to get a system which would run from April through November in Toronto and is as quiet as possible. Never thought a pump would be this tricky!

Philip

 

[mas985]

1 - True but dead is dead. Both 110v and 220v are dangerous and should be treated as such. Is 220v more dangerous than 110v, depends on the situation but with bonding and a GFCI, there is little risk with either. There are many many pools, including mine, that run pumps on 220v and if there was an issue with 220v over 110v, electrical codes would not allow 220v. So I don't think you need to be so concerned about this.

2 - You can also use GFCI breakers and then use a plug although in general, I have never seen a 220v pump motor with a plug. You need to check local code and make sure it is ok.

3 - The RPM setting depends on the height of the VRV. The higher the VRV, the higher the required RPM to maintain a positive pressure at the VRV so it remains closed. However, you will still need a priming RPM for the first few minutes of solar engagement and whatever controller you use, must support this otherwise the panels may not full prime if the RPM is too low.

Sizing a pump for solar is not that tricky. Nearly any pump will support solar so if you have no other features that require high flow rate, you can either choose a small two speed pump or a VS pump. Either will work fine. The real issue is time to payback which will be much shorter with the two speed.

 

[pmcd]

Ok, finally thought I had found a pump replacement. It is a Pentair Dynamo 1 HP, but two speeds. We currently have a one speed Dynamo (1HP) and it plugs into a GCFI plug.

The 2-speed Dynamo does not come with a plug. What does this mean? Can one purchase something to plug the pump in or does this have to be a custom wire attached by an electrician who will charge me more than the pump?!

In any case there are three(?) wires that have to make their way to a plug. Why is this so darned hard? I feel like I have gone back to grade 1. This pump is a 110v pump by default. Why would anyone sell a pump without some way of plugging it in? I do realize that most pumps seem to come this way and then the hard wiring issue comes in.

Philip

 

[Bama Rambler]

Most people hard wire pumps so most pumps don't come with a cord and plug. It's pretty easy to add a cord and plug if you need to plug it in. On the 2-speed pumps you can buy a rear cover with a switch for stopping and switching speeds.

 

[Isaac-1]

Just to clarify something Mas985 said on solar pump sizing, this partly depends on your level of concern for maximizing BTU transfer from the solar panels (potentially at expense of higher pump operating cost). Most solar panels have an optimal flow rate of around 5 GPM per panel and can tolerate up to about 8 GPM per panel, but still manage around 90% of optimal performance down to about 3 GPM per panel. However once you drop below 3 GPM per panel performance drops off fairly quickly, down to the 60% range at about 1 GPM per panel (you are needlessly trying to heat the returning water much hotter than the surrounding water, ideally you should have enough flow on a solar heater that the returning water is only slightly warmer than the pool water, I know this defies common sense, but that is thermodynamics for you)

So if you have a pump that would flow 5 GPM per panel on high, and 2.5 GPM per panel on low, you may in fact be able to operate your solar heat on low, but at the cost of losing 20-25% of your optimal heat transfer, while saving electrical operating cost. The question then becomes which is more important to you. This may also mean that you would want to run your pump on high during the first and last parts of the season when your solar panels may be struggling the most to reach your goal temperature, and turn down to low during the part of the season where they would otherwise turn off mid way through the day.

Ike

 

[pmcd]

Re: Should I replace my pump with an IntelliFlo or a Max-Flo

Some can after it is primed, but the best heating is at high flow rates, so I do not even try. I run on high when I need heat and low when I don't ... which is all winter and in the dead of summer.

You would think that the slower the flow through the panels the better it would be. Perhaps the type of panels makes a difference? It just seems that fast flowing water would heat up less. Very odd.

Other than the flow rate could a pump get the water up 10 feet at low speed?

Philip

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[pmcd]

I just don't get why water staying longer in a panel would heat up less. Is this a fact or just some thing that has become accepted without proof? Not trying to be difficult or anything but this flow through really seems odd. I would have thought the lower the flow, to a point as the water has to turn over, the higher the heat transfer.

Philip

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[Isaac-1]

I think you read that wrong, the faster the flow through the panels the better for heat transfer. Slow flow through the panels gets hotter water out them, but less total BTU's transferred.

Ike

p.s. maybe if I put it this way it will make more sense, there is a maximum temperature that sunlight can heat a black plastic tube filled with water, this is typically 180-210 degrees F with zero water flow (heating it that hot would considerably shorten the life of the plastic though) No matter how long you left it under sunlight it would not get any hotter, this has to do with the rate the panels absorb heat vs reradiate the heat. (so simple put it would never get hot enough to burst into flames, etc.) At a lower extreme this means the closer the outlet water temperature is to the inlet water temperature the more BTU's are transferred.

Alternatively maybe this will make more sense, don't think about heating the pool, think about it as moving heat from one place to another, in this case from the panels to the pool, your doing this by cooling the panels, the more water flow you have the cooler the panels will be. That heat from the panels you are removing has to go somewhere, and the only place for it to go is into the pool. Looking at it this way it may make more common sense that higher flow "cools" the panels more than lower flow.