Jandy FloPro 2 Speed Motro Swap 1 HP - 1.5 HP

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T

toofast

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May 9, 2013
993
North East Ohio
Long story short, but my PB really screwed my on this one...

The design called for my HeatPump to be able to run on Low Speed with my 2 SP Pump, see below for details, but it is a Jandy Flo Pro

http://www.zodiacpoolsystems.com/Products/Pumps/Single-Two-Speed-Pumps/FloPro.aspx

Well, it appeared that MAYBE it would, but in all reality I do not have enough flow on low speed to run the HP. Even though the pump spec says it is putting out 55 GPM or so on low, in all reality it must really be less than 30 GPM in the real world.

So I told my PB it is not working and I think I need the 1.5 HP. He said fine, but I can't return the BRAND NEW 2 DAY old 1 HP and I would have to buy another 1.5 HP pump and then pay to swap it out.

Well, that is total Crud...but it seems like I won't win this one (so much for any references he might get - wonder why these guys are so short sited)

Anyways...does anyone know if I can just SWAP the motors out and I guess I could try to sell the 1HP, or is that insane thinking and I just have to suck it up and spend another $500.

Or any other ideas - let them fly!

Thanks in advance!
 
The specs for flow rate are not real world numbers. In reality there is a pump curve and the flow rate depends on the head loss which is determined by all the resistance (plumbing, filter, heater, etc) in the waters flow path. So getting 55 GPM on low is extremely unlikely.

You can change the motor to a larger one, but will also have to replace the impeller to match and need a new seal kit.

I would keep talking to the PB as clearly they screwed up if the low speed requirement was in writing. Even if it was not, seems pretty rediculous to not swap it out.
 
Ok clear on the motor change, does not sound super easy.

For sure I will keep talking, but now I have a follow up - I tried like HECK to read and understand the Hydraulics 101, etc. so I could figure out my head loss to try and get an estimate on the real world GPM.

As you can see the flow rate on the 1.5 is 65 GPM on low vs. the 55 GPM that I have now.
However, how do I know if that 10 GPM gain in the real world will be enough ?

[attachment=0:2ionbs7s]pump specs.jpg[/attachment:2ionbs7s]
 

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It is not very easy to estimate the head loss and thus get the flow rate.

You are somewhere on that pump curve ... at MAX you could currently have 55GPM. Hard to say if the bigger pump would work or not.

If you provide all the plumbing details (number, diameter, and length of suction and return lines), then we (or Mark) might be able to estimate the flow rate.

What is the pressure reading on high and low speed? How high is the gauge relative the to the pool water?
 
Posting the same time as Jason so there may be some duplicate questions.

The end of the head curve (right most point or run out) indicates the max flow rate but the pump will never reach that point unless you have no plumbing attached to the pump. When typical pool plumbing is attached to the pump, the operating point is closer to the center of the head curve.

So before making any changes, I would assume that you would like to know if a 1.5 HP would even work, correct?


If so, a few more details are necessary.

What is the filter pressure when the pump is running on full speed?

What is the filter gauge height relative to the pool water level?

What is the backwash filter size?

What size pipe is used on the suction and return sides?

How long is the suction side pipe pool to pump?

How many suction pipes, pool to pump, are there?
 
Ok, I will work on those details...in the meantime all I know is the pressure is around 10 PSI on High and it barely registers on low speed - which was another question I wanted to ask, but didn't get around to it yet.

Oh and another silly question...is it safe to assume that IF the 1.5 HP will delivery the GPM I need that it will be a perfect match to the lines, etc...so no re-plumbing required ?
 

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Ok here we go....

What is the filter pressure when the pump is running on full speed? – 10 PSI

What is the filter gauge height relative to the pool water level? – 42”

What is the backwash filter size? – 2” Multi-Valve

What size pipe is used on the suction and return sides? – 2” Rigid PVC

How long is the suction side pipe pool to pump? – Main 1 is 36’, Main 2 is 30’, Skimmer is 61’

How many suction pipes, pool to pump, are there? – 3 total, 2 mains and 1 skimmer (I have valves on each and can turn on / off if that helps as well)

Below is the layout...let me know if you need anything else or if something is missing.

[attachment=0:3dqa6sok]pool line layout.jpg[/attachment:3dqa6sok]
 

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I am curious to see what Mark reports. I tried to use his tool, but not sure if I understand all the details/tricks.
By my estimate you should be getting about 34 GPM on low with your current pump and the 1.5HP would be around 40 GPM (not sure about this one) ... but lets see what Mark says ;)
 
Ok, I went to Marc's website to try and find the "tool" (as I am a spreadsheet junkie) and I wasn't exactly sure what to look for. I really hope your calcs are close, but since my HP should be able to run at 30 GPM I am guessing I am not quite getting 34 GPM for some reason...

I have no problem upgrading (even though PB is still fighting me) to 1.5 HP, but I still want to make sure I understand if that will be enough.

As always, thanks again and looking forward to clarification.
 
jblizzle said:
I am curious to see what Mark reports. I tried to use his tool, but not sure if I understand all the details/tricks.
By my estimate you should be getting about 34 GPM on low with your current pump and the 1.5HP would be around 40 GPM (not sure about this one) ... but lets see what Mark says ;)
Click to expand...
That's pretty close to what I got which is 75 GPM on high and 37 GPM on low. 44 GPM on low for the 1.5 HP. (Jason, did you enter 3 on line 9 for the number of runs and 43' for the average run length?).

If the spec on minimum flow is 40 GPM, it might be right on the edge and there could be something else done to push it over the top.

What size are the eyeballs and how many eyeballs/returns does the pool have?

Do you normally leave all three suction lines on at the same time?

Generally, a heater works on pressure and not so much on flow rate so one idea would be to reduce the eyeball size to bump up the pressure some. That can also help with circulation as well. Also, make sure all suction lines are fully open.

Also, if you want to download the tool, you can get it from here:

Pool Tools Spreadsheet

I used the PSI2GPM tab for the calculation.
 
BINGO - BINGO - well maybe :)

So I can't remember exactly when, but in the middle of my PB trying to figure it out, he replaced all three of the eyeballs/returns with LARGER eyeballs, saying it would HELP the HP running on LOW. Well it sounds like he has it backward.

I have 3 main returns, then 6 additional SPA JETS that are all valved independently. He told me to OPEN all return valves for max flow. Once again, sound like he got it wrong.

I DO normally leave all three suction lines on at the same time - sound like the PB got that info to me accurately.

So for testing purposes...I should be able to SHUT OFF most of the returns, and simply keep two of them open for testing. If that works, I need to get him to reduce the eyeball size on the 3 returns to keep the pressure where it needs to be.

WOW - YOU GUYS ROCK!

Can't wait to download and play with the spreadsheet - have a long plane ride ahead of me tonight. Thanks Again and I will post my results of the testing!
 
jblizzle said:
Spreadsheet needs internet access, so not sure it will work on the plane.
Click to expand...
It only needs access once per month so open it once before you leave and you should be good to go.
 
Gotcha on the spreadsheet...

Ok, test results.

I had to close all returns (except for one) to get the FLO error to go away on the HP. I was then able to OPEN one of the two returns and I could get the HP to keep running. (this is not a long term solution of course)

So if the above calcs are correct on flow, it seems like I just need to go back to my smaller eyeballs - hopefully that will allow me to run all 3 main returns open for circulation purposes.

OR I assume that a larger PUMP, i.e. 1.5 HP will also INCREASE my pressure as well, thus allowing me to run on LOW if the smaller eyeballs don't work.

Finally I think I have a final variable...when the PB first adjusting the "pressure" switch - it was working on low....with the small eyes as noted. But two things happened, larger eyes and also the filter has been working. So my pressure on HIGH started at 10 and is now at 12. PB said no need to backwash till 18 PSI (WRONG AGAIN)...I know (thanks to POOL SCHOOL) that I am on the verge of needing to backwash...but wouldn't this HIGHER PSI be "BETTER" for my HP or am I over thinking ?
 
When the filter is clogged, it sees higher pressure, but the heater would see lower pressure. Smaller eyeballs increases the pressure in the entire return line.

Clean the filter and the flow rate will increase as well as the pressure in the heater.
 
Again, Jason beat me to the punch........

The heater is after the filter and the rise in filter pressure means the pressure at the heater is actually lower.

My suggestion is to not up size the pump but go back to the smaller eyeballs and have the installer readjust the pressure switch while the filter is dirty.

Note though with a heat pump, running on low speed will reduce efficiency. Does the heat pump have a minimum flow spec?
 

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