Pump Size with Built in Cleaning System

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RC51Jim

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Jun 26, 2008
21
The house I bought a few years back has an old pool that I am finally getting around to R&R.
So after a brief attempt at searching I have a question about my pump size.

First background info:
22k in ground with 1.5k spa built in 1978.
2HP pump & 36 sq.ft. DE filter (really old kind with like 20 bolts to unscrew)
Master Supply "Turbo-Clean" system
1.5" metal pipe.

All equipment is original except the pump (original pump was 2 HP)
I will be replacing all of the equipment and really do not see why the pump is sized so large unless it has something to do with the Turbo-Clean system.
The manufacturer of the system (Master Supply) has not been able to give me any recommendations on what size pump is required to drive the system and "pop-up" the heads on the bottom of the pool.
With 1.5" pipe and I believe 26' of head I should be able to downsize the pump.

Does anybody have any experience with these systems or insight into the solution?

Thanks

Jim
 
In-floor cleaning systems usually require a fairly large pump but it depends on how they are plumbed. If there are multiple zones, then a smaller pump is possible but if there is only one zone, then you will probably need a decent size pump to run them.

1 1/2" may not be bad depending on if they used multiple runs from the pool to pad but even so, it is likely that your head loss with the current pump is well over 50'.

If you post some of the details on the current plumbing, I might be able to guide you better.

What is your current filter pressure with and without using the floor cleaners?

How many and how long are the suction side runs?

How many and how long are the return side runs?

How many zones and heads per zone are there?

Is all the plumbing 1 1/2" or is some of the above pipe larger?
 
Answers Below:

What is your current filter pressure with and without using the floor cleaners?

Floor cleaners are the only return to the pool, if the pump is running the leaning system is running unless I have switched to the spa.
With a clean filter the pressure is 10-12 PSI.

How many and how long are the suction side runs?

2 Suction runs: 1 from pool main drain/skimmers (50') and 1 from spa drain (25').

How many and how long are the return side runs?

No side returns only return is through the cleaning suystem or spa jets.

How many zones and heads per zone are there?

5 zones, 2 heads per zone.

Is all the plumbing 1 1/2" or is some of the above pipe larger?

All 1.5" pipe to/from pool.
Each of the 5 zones has a 1.5" pipe and the water valve rotaes through the zones one at a time.
Here is a link to the system:
http://www.master-supply.com/cleaning_turbo.html


Also I must mention that I am not 100% on that 26' of head figure. I will look at the pool drawings when I get home tonight.

Thanks

Jim

PS Looks like you are local to me..I work in Concord.
 
Pressure seems too low for a 2HP pump so one of two things might be going on. Either the filter guage is reading incorrectly or the 2 HP pump has a very low service factor. How confident are you in the filter pressure? One other thing to check on the pump is the service factor on the label.
 
Yeah I am thinking the pressure gauge is wrong.
I dug up the literature from when the pool was installed (previous owner saved everything!) and it said normal operation for the filter was 20 PSI.
The service factor on the motor is 1.3 so it has plenty of power.
Also they did not list the pump head on the drawings like I thought, I don't know where I got that number from.

Jim
 
The information you gave was very helpful although an accurate pressure reading would be even more helpful but let's try to work with what you have so you don't have to go out and buy a new pressure guage.

With a service factor of 1.3, which is typical of even full rated 2 HP pumps, a Whisperflo full rated 2 HP would be a direct replacement.

Also, I would normally suggest a two speed pump but in your case because you cannot return the water through normal returns, this may not work well for your pool unless you can add a separate return. The problem is that at low speed, the pressure and flow may not be enough to open the cleaner heads enough. So unless the manufacture can guarentee it, I wouldn't go this route.

So the real question is, can you reduce the HP of the pump and have the cleaner still work well? Without the specs of the cleaner, it is difficult to know for sure.

One thing you might consider is the Intelliflo pump. It is pretty expensive but since you are doing a full remodel, you might be able to get a package deal. The nice thing about this pump is that you can adjust the flow settings to get the lowest flow rate and still maintain decent cleaning while save a bunch on energy costs. In fact, in most cases, you will probably pay for the pump in only a few years.
 
So over the weekend I was out playing with the pool equipment and installed a vacuum gauge to the strainer basket drain and obtained a reading of 24". Taking into account that the instructions on the pool systems state normal operating pressure is 20 PSI, I plugged the numbers into the formula on the sticky thread and came up with 73' of head.

If I look at the pump curves on the same chart it with my 2 hp pump it gives me a flow rate of about 105 gpm; with my 1.5" pipe is it even possible to come close to that?

Jim
 
Yes it is possible to hit those high flow rates in 1 1/2" pipe. There is no hard limit although you will see "not to exceed" flow recommendations for pipe but they are just that, recommendations. The higher the flow rates, the higher the head loss so there is a practical limit as to what the pump can provide.

Second, if I read you correctly, you used the 20 PSI on the pressure side but it sounds like it wasn't measured but from a spec sheet. The filter pressure is dependent on many things so I don't think you can really go by the specifications and expect an accurate answer. Your pressure could be much higher or lower and really needs to be measured. You can probably use the vacuum guage (if it also includes a pressure guage as most do) and put it on the other side of the pump to measure the pressure.

Also, did you have a pump head curve from your pump or were you using the one in the sticky? The sticky version was meant to be an example and may not be very accurate for your pump. Since your service factor is about the same as a Whisperflo, you could use that pump head curve which would give you about 90 GPM. Still pretty good flow rate but if the 20 PSI was not measured, it could be much different.
 
Yeah I got the 20 PSI figure from the system operating instructions from the pool builder (Geremia Pools). It states that the normal operating pressure is 20 PSI and backwashing is required if the pressure rises more than 10-12 PSI above that.

The pump I am currently running is a Pentair Challenger series 2 HP.
I also have a 2 HP Sta-Rite Dura-GlasII that I picked up from a buddy who did not need it anymore, still works good though. I was originally planning on replacing the worn out Challenger with this but now am considering the VFD pump.

I just need to nail down a flow rate in order to determine my filter turnover to see if changing to a VFD would even be worth it.

Sooo

I am getting some parts to rig the existing filter back together temporarlily so I can
1. Run it and keep the pool from getting too dirty while I am planning this project.
2. Get some accurate pressure readings.

Jim
 
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