Standard vs. Variable speed pump

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Bhebert449 said:
Does the Easy Touch display integrate with the pump settings?
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Yes. The pump is directly wired to a breaker in the EasyTouch panel and is powered all the time (unless you throw the breaker). There is then a serial communication cable that connects the electronics of the pump to the personality board in the EasyTouch. When the ET panel is controlling the pump, the front control panel on the pump is disabled. When the EasyTouch is powered off or the serial communication cable is removed, the front panel of the pump controller is active.
 
Cool, Thank you for all of the feedback. I like the idea of being able to run the pump longer at lower RPMs to better control the salt cell. The only concern I have is the spa spillway and how much flow it will require and still reap the advantage of low RPMs for the energy savings.
 
You don't want to run a spillway all the time if you can avoid it. Will you be getting a separately plumbed spa return or spa "make-up" line? I have a spa with a spillway and there are the normal spa jets as well as a single return about 12" above the bottom of the spa. So, when in pool mode, I can split the water return using a three way valve between the spa and the pool. That valve is automated so I only activate the spillway for about 90mins per day.

PBs will tell you that "you absolutely have to run the spillway all the time so that the spa sees fresh water" but that is not true at all. As I said, I only run my spillway 90mins per day and that's enough.

NOT running the spillway has two effects -

1. Lower overall pump speed for pool mode;

2. Reduced aeration

I know you're not anywhere near wanting to learn about water chemistry, but aeration of pool water by bubblers, waterfalls and spillways is the largest single contributor to pH rise in a pool (through the process of carbon dioxide outgassing). So, reducing the use of water features at unnecessary times reduces the aeration of the water and helps to keep pH under control.
 
There will be a diverter valve for the pool and spa. My understanding is when in spa mode the valve will close off the pool returns and send all flow to the spa. I guess I need to ask for the extra 3-way valve so I can control the spillway independently while in pool mode, correct? If I don't have this, I will likely not see any benefit of the VS pump since the spillway will require much higher flow to function properly.

This is getting really complicated. :confused:
 
B,

Your EasyTouch has three standard modes...

Pool mode.. This is where all the water is sucked from the Pool by your pump and then pushed through the filter, heater and SWCG and then back to the Pool.

Spa mode.. This is where all the water is sucked from the Spa by your pump and then pushed through the filter, heater and SWCG and then back to the Spa.

Spillover mode... This is where all the water is sucked from the Pool by your pump and then pushed through the filter, heater and SWCG and then back to the Spa. Water going into the Spa and not draining out causes the water to overflow into the pool.

This is standard setup, but just in case you might want to make sure your Pool Builder plumbs your equipment pad so you can have these three standard operating modes.

Thanks,

Jim R.
 
SpringPool said:
I'm not sure there is a metric. I've found you need to run the pump for different reasons depending on what's hooked up to it. Also here the study referred to http://consensus.fsu.edu/FBC/Pool-E...4_study-efficiency_of_circulation_systems.pdf

1) filter the pool (2 hours should keep it clear see paper above)
2) SWG (dependent on size of pool, FC loss on a given day...)
3) Suction cleaner
4) Water features
5) Skim the pool ( I can swim with stuff floating in the pool but others like to see a clear surface) a great reason to have a VSP. I can set it to 1400 rpm on my pool and it skims the pool and my overflow from the spa stays fully covered in water.
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Nice post. I like the white paper you reference in the link! Thanks for sharing.
 
Jim’s right about the three modes but here’s what I don’t like about spillway mode -

1.. it runs ALL the pool water through the spa jet returns creating a lot of unnecessary aeration

2. Water only flies through the spa reducing circulation in the pool.

When my single spa makeup return is allowed to siphon water off the pool side returns, I get water returned to the pool and the spa with no aeration from the jets. It’s a little more complicated plumbing-wise but not a whole lot. I like having both options - EasyTouch spillway mode and the extra return setup.

Just my opinion.
 

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Is it a true spillway or a spill over. Basically is the water going to flow over the edge or will it drop over the edge.

The reason I ask is if its a spillover aeration would've almost zero. As for the vsp if ty don't change the pluming it will just trickle over the edge and drop into the water. This would cause some aeration. So if the PB can't or won't change the valve to a 3 way I don't see t as that big of an issue.
 
The spa will be raised 18" and will have flagstone step downs. So the water will flow over the edge. I just want to ensure I have good flow out of the spa for effect.

Can I simply add a 3 way valve to allow adjustments to the flow into the spa when it is recirculating with the pool?
 
Folks,

I'm coming into this post late and I've read a lot of informative threads on tfp about the VS, multi-speed, Vs single speed pump issue. I think a lot of people are using the term efficiency pretty loosely. There are two factors that allow owners to save money from something more advanced than a single speed pump:

  • One is running the pump at a slower speed that consumes less total power because the work performed is less than at the higher speed. Often the pump is less efficient at this speed but the total work requirement more than offsets the efficiency reduction.
  • The other way to save money is to run at a slightly different speed to get the maximum efficiency and the flow rate is roughly the same.

So I offer this centrifugal pump curve to support this below (sorry about the scale, I couldn't seem to adjust that right). Please note that sometimes you can increase flow rate and increase efficiency. The curve presented is for a "generic" centrifugal pump. But all centrifugal pumps have the same physics so they have similar curves. There are all kinds of factors that affect the efficiency such as the amount of recycle and leakage around the blades and the shape of the housing and distance between the tip of impeller and the housing etc. They do not all improve with slower speed.

It's very clear to me that having multi speed capability is a huge advantage in most cases. Now is it really worth 2X for a VS versus a 2-speed? That depends a LOT on the situation. If the pump is going to have to run mostly flat out to run the solar heater or something else so that you are really at max speed most of the time then it's really hard to pay off the big bucks for a VS. But there certainly are situations that easily pay off the VS... it just depends.

I hope this is helpful.

Chris

generic pump curve.jpg
 
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Bhebert449 said:
The spa will be raised 18" and will have flagstone step downs. So the water will flow over the edge. I just want to ensure I have good flow out of the spa for effect.

Can I simply add a 3 way valve to allow adjustments to the flow into the spa when it is recirculating with the pool?
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ok so when you want it to flow instead of trickle you just need to increase your rpm on the pump. We have a fountain in the spa and bubler and that's what I do. For a while I had it on a schedule to run automatically but when no ones outside I didn't see the point of running it

This is one reason why I think automation is great to have.
 

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