I really need your Help/Advice

[HarryMichael]

Last week we had a meeting with the PB to address some questions about our up-coming pool. I could not make the meeting so my wife went with our list of questions.
Let me say up front that I don’t think I know more than the pool builder…but being on this list for a few weeks now, I really respect the advise I’ve read here and I really need to hear your advice on three concerns I have about pipe size and pool pump and filter.
The pool will be a Trilogy Fiberglass, 15x34 x 5’6" deep, 8900gal.
He said he will use 1 ½" PVC with a Hayward Power Flo 115V pump with the Pentair Clean & Clear CC 50 cartridge filter. Reading what others have done on this list, it seems that most get 2" PVC. And that pump he suggested is a pump for an above ground pool???…is not a 220V pump the way to go. I wanted the Pentair WhisperFlo 1HP 220V and he told my wife I did not need it for the size pool I was getting.
So, what he recommends:
1- 1 ½ PVC
2- Hayward Power Flo 1hp 115V Pump
3- Pentair Clean & Clear CC 50 cartridge filter

I was thinking:
1- 2" PVC
2- Pentair WhisperFlo 1HP 220V
3- Pentair Clean & Clear Plus CCP 240 cartridge filter

This EQ he spec'ed comes with the price he quoted. If what he is recommending will work...fine, but if it is better to go with the other stuff, please let me know. I'll pay the extra if it's the best way to go. We Need your thoughts and advice,
Regards,
Harry

 

[kenlorz]

To my knowledge the power-flow IS an AG pump and is NOT self priming.( We had a power-flo lx on my AG pool..great pump forthe applicantion) This should only be a problem if your pump will sit above the waterline of the pool. Otherwise I don't think it's a good idea. As far as size gose a 1hp may actually be overkill for that size pool. I'm 18x38-20K gal and I'm on a 1hp superpump and so far it works very very well.(pool is less than a week old!) We also only have the 1 1/2 " plumbing ..but it's tiger-flex with minimal fittings and no splices...clean filter running @ 7psi.

If you can run 220v I would do it..all motors that are switchable from 110 to 220 will work best on 220. It will cost more to set up..but your motor will last longer and run cooler.

 

[HarryMichael]

Last year we had a new electrical box installed.. lots of extra space for pool eq and they also left enough wire to complete the hook-up...just need to add breakers.
On the pump, maybe you are right about the 1hp, maybe 3/4hp??? But most pool owners tell me whisperFlo 220V is the way to go. I'll have another chat with the PB at the end of the week but still would like to hear any opinions here
Harry

PS..Thanks Ken

 

[SeanB]

You won't regret oversizing the filter.

 

[kenlorz]

Yep...it's ok to oversize your pump but you must make sure that the pump and filter are matched for each other. If your filter is too small (no matter what type) you'll just blast the dirt right through it.

 

[Ohm_Boy]

1 hp at 120v is 1hp at 220v. The difference is that at 220, the current required is less, so smaller wire can be used.
Here's the breakdown...

The conversions:
1hp = 746 watts
Power(watts) = Volts * Amps (1w = 1Volt * 1Amp)

The math:
So, with 1hp, (1*746) = 746 watts
746watts / 120volts = 6.22 amps
746watts / 220volts = 3.39 amps

There are some idiosyncrasies, like eddy-currents/copper losses and motor slip/torque loss, and accounting for reactive aspects of AC motors, but you're somewhere around 6 amps for low voltage, 3 amps for high.
Not a lot of difference, but there are some subtleties:
1) You may get better starting torque at 220.
2) Using less current, your motor circuitry is less succeptable to losses from dirty contacts (relays, timers, etc.)
Doubtful that any of this will offset the cost of the extra breaker though, so it's pretty much whatever you want.

Like I said, generally at higher voltages, the wire size can be smaller. That's why major power transmission is done at voltages over 110K volts. Low current means low line losses. But in your case, I doubt it'll make any difference.

Basically, you want as small a motor as you can get by with which can turn over your pool water, with a little margin.

 

[Poolidiot]

"will work best on 220. It will cost more to set up..but your motor will last longer and run cooler."

Cost more to set up? Not electrical wise it will not. 220 volt will cost less to run, it will take the same amount of wire from breaker to pump, therefore no more money for wire or labor to pull wire, Only thing would cost is the breaker, the you would have to have a 2 pole breaker instead of 1 pole breaker (maybe $10.00 more) So if your builder tells you that it is more to install a 220 motor instead of 120 then he is not to be trusted. My advise would be go with the 220 motor.

 

[kenlorz]

"Only thing would cost is the breaker, the you would have to have a 2 pole breaker instead of 1 pole breaker (maybe $10.00 more)"

I Just bought a 220v 20A square D QO GFIC breaker and it was almost $100.00. There is no other way that I know of to gfi protect a 220v circuit....and nec code states your pump must be gfi protected.

 

[Poolidiot]

Yep and your single pole breaker would need to be GFI as well. And even if it did cost you $100.00 more you would make that up the first 2 to 3 months of running your pump (running 24/7 just for argument)

 

[kenlorz]

I don't belive running 220 or 110 makes much difference cost-wise. watts is watts is watts. If you double the voltage..you half the current draw and visa-versa. But that dose not change the amount of wattage a pump will draw...with the exception of your start-up spike wich lasts all of a few m/s. I=P/E...so a 750 watt motor @ 120v will draw 6.25 amps running the same motor 750 watts @ 220v will draw 3.40 amps..on each 120v leg. So it all comes out in the wash....your gonna pay the electric company no matter what.

 

[Poolidiot]

Sorry kenlorz, but i can not agree with you

 

[chem geek]

Ohm_boy and kenlorz summarized the issues quite well. There is little difference in power between 220V and 110V so unless they really skimped on the smaller wiring they could use at 220V, there should be less resistive losses at 220V. The thing is, I have no idea how large or small these are except I suspect they are rather small.

Poolidiot, you say that 220V costs less to run. Do you know by how much and is this from experience or theory and if the latter can you please explain why? I'm not doubting anyone here, but would like to get to a better definitive consensus. Are we talking about two separate pumps, each designed for their own voltage rating but both advertised as 1 HP or are we talking about one pump with a switch that does something to make 110V and 220V both be approximately 1 HP in power draw? I also assume the Service Factor is the same at both voltages.

If we completely ignore inductive losses and the power transfer to the water (and those are huge things to ignore), the power from a fixed resistive load is derived from E=IR and P=EI so that P=E²/R so if there is no switch to change the windings, then double the voltage would quadruple the power loss. I thought that switches on these pumps changed from two parallel sets of windings in 110V mode to putting these two sets in series at 220V. If each winding has resistance R, then that changes the overall resistance from R/2 to 2R which is the factor of 4 desired to keep the power constant. By the way, when I refer to "P" in these equations, that's resistive power loss and will in no way be close to the 1 HP total power. Typically at least half of the power is transferred to the water (as pressure times flow rate) and I thought that the largest other losses were inefficiencies at transferring electrical energy to the water.

I do know from my analysis of Intelliflo pump curves that it "appeared" that there was a fixed power loss of 80 Watts regardless of RPM. I had assumed that this was the resistive loss and if that is the case then maybe that would be the difference. However, if there is a switch between 220V/110V changing the series/parallel aspect of the windings, then this 80W would be the same at both voltages.

 

[sevver]

I think it costs more to run because there is an extra wire, and the size is larger, plus the different breaker. But really, the cost difference should not be much, labor is generally the major cost factor. And pulling 4 wires instead of 3 is still pulling wires. And putting in a double breaker instead of a single is still putting in a breaker. I don't really see how much more it could be. If it is alot, then you could pull the wire yourself. Or find someone to do it on the side.

 

[KurtV]

If I remember my 20+ years ago electrical engineering class:
P=VI
V=IR
so P = I²R
where
P is power
V is voltage
I is current

We can use the P=VI equation to determine the power used to actually do the work and, as several people have stated above, that consumption is the same whether you use 220 or 110 (double V and halve I or vice versa).

However, the losses in the motor and in the wiring leading to the motor (e.g. the heat produced by the motor) are governed by the P = I²R equation. There, because the I term is squared, it has a much larger impact on the bottom line.

 

[chem geek]

The formulas you gave are the same as what I did, except I essentially went from I²R and substituted from E=IR or I=E/R to get (E/R)²R = E²/R so that it's easier to see the direct relationship between voltage and power. It's still a square relationship in either case -- the factor for resistance is what has a different relationship. What I did was only valid if the current is determined completely by the resistance being examined (which is what we are assuming in this case). It's better to use I²R when looking at parts of a circuit since the voltage in that case will only represent the voltage drop across the resistance being examined.

If we assume the parallel/series split I was describing, then the 110V goes through two windings done in parallel. If each winding has R for resistance, then the net resistance seen from outside the motor is R/2 so the total current will be I=110/(R/2) = 220/R but the current will be split in half for each winding so will be 110/R in each winding (which makes sense) while the resistive power loss is I²R so is (110/R)²R for each winding so the total power loss is double this or 2*(110²)/R. The 220V goes through two windings done in series. The net resistance is now 2R so the total current will be I=220/(2R)=110/R while the resistive power loss is I²R so is (110/R)²R = 110²/R IN EACH WINDING so is 2*(110²)/R for both windings together ( the formula looks more correct if one looks at total resistance (Rt = 2R) as in (220²)/Rt ). This is the same power as with 110V.

Notice also that the current through each winding is the same (110/R) regardless of configuration (parallel or series). If one were to build a 110V motor (not switched) with one winding, then indeed it would need to be thicker wire to have less resistance and have the same amount of resistive losses as a 220V motor also with one winding.

 

[Ohm_Boy]

At the power meter, it's still just watts. And that will be based on I * E, as the power meter has no idea about the resistance of your motor.
Unless your motor is just more efficient on 220, 746 watts gets registered on the ol' KWH meter, and that's what hits the wallet.
Technically speaking, the motors are essentially the same, with a pair of windings in either series for high voltage, or parallel for low voltage.

There will be a difference of beaker cost, and a timer may be cheaper for 120v, but the operation costs should be way too close to see a difference.

If your pool designer wants to unload a 120v motor, and you tell him that you want 220, you MAY can get him to discount the 120v just to avoid any hassle. Hmmm.... a cheaper motor... now that's a reason to make a choice.

 

[JohnT]

No difference in power consumption, it's just easier to get 220 to the end of the wire because the current is lower. 220 allows you to use considerably smaller wire.

 

[Ohm_Boy]

No difference in power consumption, it's just easier to get 220 to the end of the wire because the current is lower. 220 allows you to use considerably smaller wire.

Technically, yes - the current with 220v is less, therefore the drop across the wire is less.
Practically, however, this should end up with a #14 wire either way. So, if it's 50 feet from the breaker panel, you've got something like 0.2 ohms over the full 100 feet, so at 6.5 amps you may drop 6.5*0.2= 1.2volts, and at 3.25 amps, you'll lose 3.25*0.2= 0.65v. Granted, there's a difference, but it's pretty nominal in the real world. If your builder is wanting to use #18 or something, I'd make the argument to bump it to #14.

I concede that once the wire nuts and terminal screws and contacts have gone through some thermal cycles, the overall circuit resistance could go up, and those problems are more likely to noticeably manifest themselves in a 120V circuit, but left unchecked, those issues, if they exist to that level, will likely escalate to a problem eventually anyway.

I PERSONALLY prefer the higher voltage motors (I used to work on 4160 volt motors*), but in all practicality here, the difference is so minimal that it's really not worthy of being a design criteria, in my opinion.

So, for me, the real bottom line is going to be the installed price and/or product lead time. If one ends up cheaper to install, or one will add weeks to the timeline, I would base my decision on it.

I will say again that the entire argument *could* be used to try to lever the builder into discounting a stock motor to avoid the hassle of a change, but I can't say how effective that tactic may be.



*Now, those puppies will make you cringe when you punch in the contactor by hand to start them up manually after a rewire!

 

[induce]

Our pool is about 3 weeks finished.
my PB wanted to run 1.5 pvc and 1.5 hp pump. I changed it to 2" pvc and hayward northstar 2-speed pump. LOVE it.
I went with a cartridge filter also.............he is coming back Monday to change it to sand @ my request. Charging me less thean 4 extra cartridges would cost.
I have a hayward 4025 with 4 carts and boy, what a PIA to clean. we had a HUGE rain and some of the unfinished landscape let muddy water run into the pool. i've had to wash those Dang cartridges twice. Shut it all down, take apart, spray off all 4 carts, soak, spray again, it's muddy as heck everywhere by the pad, hot, PO'ed.
This is our 2nd pool, first had 32k gallons and sand filter.......flawless.
this one, 22k and changing to sand.
it's cake, backwash and done. maybe add some DE via skimmer to "improve" sand, but really don't need to. plus you can add most pool chemicals via skimmer with a sand filter, that is limited with a cart filter.
my 2 cents.