Dazed and Confused

[RMcGirr83]

Like the Led Zeppelin song. After viewing my electric bill for the past few months, have been going round and round with the PB as to why they didn't install a variable speed pump instead of the Jandy Stealth single speed pump (1.5 HP with 1.1 SF). Finally got to talk to someone who knows something and he stated that my TDH is about 78 and is recommending I go to the Jandy VSFPH270JEP pump.
Why would I have to go from a 1.65 HP pump to a 2.7 HP variable speed pump and tha TDH just seems completely nuts. Pool is kidney shaped 32x16 and is roughly 25 feet from pump. Two skimmers on each end, two main drains three return lines and two bubblers with a 300 sq ft cartridge filter. That's it, no waterfall, no bells nor whistles.

I just can't wrap my head around the need to increase the HP nor can I wrap my head around the quote of $2k to purchase and install it.

 

[Texas Splash]

I don't get that either. In reality, a reasonable 2-speed would probably serve you just as well, probably for a fraction on the electric cost. I run mine on low alomst 24/7 since I'm out in the country with lots of surface debris. Still others like @JamesW and @mas985 area very adapt to TDH issues. I suspect one of them will help you out a bt more.

 

[RMcGirr83]

Howdy from the west side of Texas

 

[mas985]

How long are you running your pump each day? My guess is a lot longer than you really need to.

Also, ignore the max HP rating for VS pumps. They are "variable" meaning you can set the RPM and effectively the HP of the pump to what ever you need. That is their advantage. Not to mention the energy and money that is saved because of the variable speed.

 

[RMcGirr83]

Not long now as the temps have increased. When temps dip below 36 freeze protection kicks on. Not sure how long it ran then.
Biggest question is why would I go from a 1.65 single to a 2.7 vs? And that TDH I was given just seems completely wrong.

 

[tstex]

You were referring to higher electrical costs, not performance.

The single speed runs at 3450RPM and is maxes at 1.65 HP...the VSP can run at a lot lower RPM's [and lower electric costs] and still match the water movement of the 1.65HP pump. However, you could run the VSP at a much lower RPM rate and for longer periods [and a lot less electricity] and achieve better water movement than the 1.65HP pump

 

[RMcGirr83]

Sorry, I didn't think I was "complaining" about anything. Simply stating that the increase in electric bill started the whole topic with the PB.

Dazed and Confused is the name of the topic and I did state this

Why would I have to go from a 1.65 HP pump to a 2.7 HP variable speed pump and tha TDH just seems completely nuts. Pool is kidney shaped 32x16 and is roughly 25 feet from pump. Two skimmers on each end, two main drains three return lines and two bubblers with a 300 sq ft cartridge filter. That's it, no waterfall, no bells nor whistles.

I just can't wrap my head around the need to increase the HP …

which is the dazed and confused part.

Why would I need to go from 1.65 HP to 2.7 HP if simply going from single speed to variable?

 

[mas985]

Two reasons to go with a higher HP VS pump versus a lower HP VS pump. Noise and efficiency. At the same flow rate, the higher HP pump will run quieter and use less energy than the lower HP pump because the higher HP pump can run at a lower RPM for the same flow rate.

 

[tstex]

I changed it to "higher electrical cost" as opposed to complaining...no offense intended

 

[RMcGirr83]

@mas985 That makes sense. I do plan on running it 24\7 at lower rpms and boosting it up when adding chemicals.

Does TDH come into play much when considering a variable speed pump?

@tstex, none taken at all. It takes quite a bit more for me to take offense to something. If you had drank all my Scotch or bourbon then we'd probably have an issue. Lol

 

[Jimrahbe]

83,

I have a 3 HP IntelliFlo pump that I run 24/7 at 1200 RPM most of the time.. My cost is less than $20 bucks a month..

As Mark says... you almost can't have too much HP with a VS pump.

As far as quiet goes, when the pump was new, I had to actually touch it to make sure it was running at 1200 RPM...

Thanks,

Jim R.

 

[mas985]

Does TDH come into play much when considering a variable speed pump

No. TDH effects the flow rate a pump can produce but in most cases, knowledge of it is really not all that important for any pump, VS or not. However, minimizing TDH can improve the efficiency of a pump but if the plumbing is already installed and is in working order, there isn't much that can be done about that anyway without significant cost. So in most cases, you can ignore TDH unless you are trying to troubleshoot something.

So who was it that said the TDH is 78 and how did they get to that number? Without pressure measurements or a hydraulic head loss model, you can't accurately determine TDH.

 

[Teald024]

Biggest question is why would I go from a 1.65 single to a 2.7 vs?

The power values that are listed on the side of the motor are rated power for the motor. Those values don't actually say how much power the motor will deliver. The motor will deliver the power it needs to push the water through the pipes. The single speed 1.65HP pump always spun at 3450 rpm and pushed X amount of water through your piping and consuming a bunch of power, lets say 1.5HP. When you slow the pump speed, you greatly reduce the power consumption.
The likely reason they chose a 2.7 HP variable speed pump is because that is a typical power rating for a VS pump. You won't use 2.7 HP, but only a fraction of that power. It's like saying you have a 400HP engine in your car. Rarely will you ever use the full power capability.

 

[RMcGirr83]

So who was it that said the TDH is 78 and how did they get to that number?

The PB, according to the Mrs. who was on the phone with them, they read it out of the brochure for the pump (which makes zero sense I guess unless they know what the flow rate is when the pump is cranking). My wife overheard one person say, who has been there a while, "I don't know what he's asking" which didn't really give me warm fuzzies.

I guess the easiest thing for me to do would be to hook up a flow meter, once I know the GPM I'll know what the TDH is from the attached (I have the stealth SHPM 1.5)

 

[mas985]

Actually, there are far easier methods of determining TDH. There is a spreadsheet in my signature that can help by using filter pressure and a rough description of your plumbing.

But again, why do care what the TDH might be?

 

[Teald024]

I wouldn’t bother with a flow meter, unless you have an aching burning desire to study the unnecessary ( aka a scientist). As backwards as it sounds, knowing TDH or flows isn’t part of this decision tree.
An equivalent power 2speed pump will save you a lot on your electric bill and be cost effective. Run on low speed for general use and high speed when you need to. If you are handy enough to install a flow meter, then buy a 2 spd pump and install yourself.
A VS pump is more expensive, but can be dialed to any speed you want. It will take quite a while for payback on this choice.

Another major factor is the run time per day. Most people don’t need to run the pump 24/7. Cutting back on runtime can offer significant savings and has no cost to you unless you install a timer.

 

[RMcGirr83]

Mas, was curious as I see the terminology when looking at pump flow charts.
Teald, thanks very much that clears up quite a bit.
Now for the $1,000,000 question, which pump, or motor, to swap with a Jandy. And yeah I'm pretty handy. Have setup home theater systems, as well as run lines for whole house generators ( with the blessing of an electrician of course). Wouldn't have an issue swapping out the pump or even swapping out the motor on the current pump if that's an option.
Thanks all, learning a ton. ?

 

[mas985]

A very inexpensive and simple option is to replace the current pump impeller with a lower HP impeller. The pump will then draw the same power as the lower HP pump. You can still use the existing motor too. Depending on how low you go, you could save up to 40% in energy costs.

Another option is to replace the current motor with a two speed motor so you can run on low most of the time but still have the higher flow rates available. This will save about 75% in energy costs on low speed vs high speed but the motor cost is more up front.

 

[RMcGirr83]

There is a spreadsheet in my signature that can help by using filter pressure and a rough description of your plumbing.

Outstanding, thanks very much for that. Really awesome.