Community SPA pump really noisy and using up 2.5KWh

[RandyG]

Hi there,

I've already learned a lot from this forum but now I am kind of stuck since I'm no expert.

I hope you guys can help me out.

I live in a complex that shares a spa. The spa is next to my backyard and, after some kind of retrofit, it's now really REALLY noisy–annoyingly so. I can't enjoy my backyard anymore.

Before whatever work they did, the pump was running at 1800 rpm, it was relatively quiet and only consumed about 300W. Now it's on at 3500rpm, noisy as heck, and consuming 3.5KW!!

I talk to the community manager and he said that, for health reasons, the pump has to run at that speed. The spa is relatively large, about 6-8 people (8' diameter), but I can't believe that it needs to run that fast and consume that much energy. I've lived here for years and it was never an issue before.

To be clear this is the pump consumption while the jets are not on.

The pump model is PENTAIR INTELLIFLO VR + SVRS.

If the pump speed is lowered to a quiet level, the PSI meter reads about 3, and I am told that's not enough to circulate the water and satisfy the health dept. guidelines.

I have a few questions:

1) Is is normal for an 8' spa to require a pump that runs at 3500RPM and uses up 2.5Kw?
2) Is 10PSI a requirement for the pressure?
3) Would it make sense to run the pump at night (when we can't hear it) at that speed and lower during the day (when we can't enjoy our little yard)?

Thank you so much for any answers you can provide.

Randy

 

[cowboycasey]

make them build a pump house and insulate it

if it a community you can get them all to vote on it...

There is no PSI level by law that I know of or ever heard of, that does not mean there is not one...... a high PSI is from the design of the plumbing, my 1hp intelliflo on high is barely heard at 10 feet and it runs at 13 PSI

 

[mas985]

1) Yes. You need lots of power for spa jets. Especially that many. However, for just normal circulation when people are not using the spa, you should be able to reduce the speed. Do they have a separate pump for the spa jets or just a single pump?

2) No. Pressure can be anything. Every setup has a different normal pressure.

3) Again, they should only need to run at high speeds when using the spa jets unless they have a separate jet pump. Then the circulation pump could always be run on a lower speed.

Also, as far as I know, for commercial pools and spas, the turnover time needs to be 6 hours or less so you really shouldn't need high flow rates for that. Especially in a spa.

 

[RandyG]

make them build a pump house and insulate it

if it a community you can get them all to vote on it...

There is no PSI level by law that I know of or ever heard of, that does not mean there is not one...... a high PSI is from the design of the plumbing, my 1hp intelliflo on high is barely heard at 10 feet and it runs at 13 PSI

Thank you cowboycasey. Yes, the pump house (even a small one around the pump unit - like a dog house) is one of the ideas I've had, but I still can't believe that we need to run the pump at 2.5KWh for 14 hours a day.

Really appreciate the reply!

 

[RandyG]

1) Yes. You need lots of power for spa jets. Especially that many. However, for just normal circulation when people are not using the spa, you should be able to reduce the speed. Do they have a separate pump for the spa jets or just a single pump?

2) No. Pressure can be anything. Every setup has a different normal pressure.

3) Again, they should only need to run at high speeds when using the spa jets unless they have a separate jet pump. Then the circulation pump could always be run on a lower speed.

Also, as far as I know, for commercial pools and spas, the turnover time needs to be 6 hours or less so you really shouldn't need high flow rates for that. Especially in a spa.

Thank you for taking the time to reply Mark.

Yes, they have 3 pumps. Two of which only come in when people are using it.

So there's a circulation pump running at HIGH 3500RPM and using up 2.5KWh which sounds really excessive to me. But I'm no expert.

About turnover, how can I know/calculate the turnover rate?

Sorry for all these questions!

 

[mas985]

The Intelliflo at full speed and 2500 watts will have a flow rate of about 76 GPM. At most that spa is probably 1000 gallons. So the turnover rate is once every 13 minutes. About 24x what it needs to be. So I don't think turnover is an issue.

But are you sure about the wattage. The Intelliflo goes up to about 3.2 kw with low head loss so 2.5 kw is pretty low for full speed and would indicate fairly high head loss.

 

[RandyG]

Hi Mark,

Thanks again for helping me out with your answers. And thank you for confirming that something must be wrong with requiring the pump to work that hard. I'm no expert, but I can't imagine having to flow that much water 14 hours a day.

I am not sure I understand about the concept of head loss (I've tried to learn as much as possible from this board, but my brain is starting to fill up ). But as far as wattage goes. the pump has a digital meter on it; it's part of the controller, I can see the KWh go from about 300W at 1800 RPM to 2.5KWh at 3500 RPM.

BTW, I don't know what full-speed might be, but it has 4 settings (1-4) at 3 it's nice and quiet, but at 4 it screams like a banshee ... although I've never heard a banshee and I'm not exactly sure what it is ... But its screams might be preferable to this pump.

Thanks again for sharing your knowledge.

Alberto

 

[mas985]

3450 rpm is full speed.

Do you know what the filter pressure is at full speed?

 

[RandyG]

3450 rpm is full speed.

Do you know what the filter pressure is at full speed?

I'm not sure where the filter is (shows you how much I know) but there's a gage with a PSI scale that reads about 10 at full speed (i.e. 3500) at lower speed (1800) it's about 2 or 3PSIs, the scale does not go lower than that. I am not sure what a good reading for the filter should be.

Thank you!

 

[mas985]

The pressure should be much higher than that at full speed which could mean that there is blockage in the suction line.

Does it sound like the pump has a bunch of rocks in it? It could be cavitating.

 

[Isaac-1]

It sounds to me like someone has confused GPM (Gallons per Minute) with GPH (Gallons per Hour) or made some other similar mathematical mistake

 

[RandyG]

The pressure should be much higher than that at full speed which could mean that there is blockage in the suction line.

Does it sound like the pump has a bunch of rocks in it? It could be cavitating.

Thank you Mark, I can't tell if there are rocks but I am glad that you seem to confirm my hypothesis that it should not take that many RPMs (and KWh) if everything was working.

Thanks again.

- - - Updated - - -

It sounds to me like someone has confused GPM (Gallons per Minute) with GPH (Gallons per Hour) or made some other similar mathematical mistake

Thank you Isaac. Not sure about calculation mistake, but I am beginning to think that there has been some installation mistake of problems with the suction line (as Mark suggested.)

Great to have some experts on board, I really appreciate the advice.