Sand blowing out when backwashing

[waterman5416]

Hi, I saw a couple old threads that were closed so I'm posting a new one.
I have an above ground pool that has blown sand out the discharge since pool was installed 3 years ago.
The installer originally installed hoses backwards. I realized after seeing allot of sand at the bottom of the pool (sand not debree) and in the driveway(allot).
At that point I switched hoses inspected and changed spider gasket (no luck).
Could the pump be to powerful? My last pump for 15x30 pool was only 1 hp. This motor is 1.5
At the end of last season I replaced the sand inspecting all internal parts carefully and they were fine.
Opened pool and vacuumed to waste. Still alot of sand discharged to driveway. 3/4 gallon bucket full.
Pool: 24 ft round above ground, salt water, Hayward S180T 18"sand filter, 1.5 powerflow pump.

Thanks in advance for your feedback.

Tony

 

[Texas Splash]

Welcome to TFP! Before we evaluate the pump's strength to the filter, let's recap a few things:
1 - Do you know what brand of sand was installed in the filter?
2 - Have you opened the filter this season to see how full it is of sand?
3 - You say it's been blowing sand since Day 1? Did anyone ever consider the MPV diverter or body may be defective?
4 - Powerflow? Is this a Hayward Power-Flo Matrix pump?

Let's start there and see what we can do.

 

[waterman5416]

I just changed the sand in the pool filter when I closed the pool with quikrete pool filter sand pn 1153.
When I changed sand, I inspected all laterals, and they were good. I followed directions including filling partially with water before pouring in new sand as not to damage laterals.
I didn't look at the new sand due to it never being used but I did put in the correct amount as specified in mfg instructions.
The pump is a hayward power-flo lx 1.5 hp.
I haven't considered mvp (vari-flow xl sp0714T) being defective but, did replace spider gasket along with piece is was glued to 1 unit along with all associated springs and orings.

 

[waterman5416]

Is there anything else in mvp that could have been damaged due to installer hooking up hoses backwards?
It was backwards for 3 weeks. I figured the gasket was the only thing that was damaged

 

[mknauss]

quikrete pool filter sand

Be aware that members have had issues with Quiikrete Pool Sand.[4] Members find that Quikrete Pool Sand is too fine and perceptibly heterogenous (i.e., not filtered to #20 specifically).[5] It does not filter well and tends to blow back into the pool. A search in the Forum can provide more information about the issues.

Sand Filter Use and Care - Further Reading

www.troublefreepool.com

 

[JamesW]

15 gpm/sqft is ideal for backwash (26.25 gpm).

20 gpm/sqft is maximum (35 gpm)

Your pump can do 90 gpm, which is 51.4 gpm/sqft, which is way too high.

https://hayward-pool-assets.com/assets/documents/pools/pdf/manuals/perflex-IS180T90.pdf

Power-Flo LX | Pumps | Above Ground Pool Pumps - Hayward Pool Products

Hayward PowerFlo® LX above-ground high efficiency pumps are built to withstand even the most demanding pool conditions combining durable construction with proven performance.

www.hayward-pool.com

 

[Texas Splash]

@JamesW, are those numbers based on high or low speed?

@waterman5416, I have a Power-Flo and it's a 2-speed. Is yours as well? If so, do you backwash on high or low speed? I was curious if it was possible to backwash on low if perhaps high speed is overwhelming the filter.

 

[JamesW]

The numbers are for high speed.

If you have 2 speeds, then you should only use low speed.

 

[waterman5416]

Thanks for all your input.
I did notice the quikrete pool sand was finer than i took out but, the problem was the same.
I only have a one speed pump. I'm going to do some research on switching motors due to pressure.

Thanks to all. For Now

 

[mknauss]

You likely can also downsize the impeller to reduce the flow rate and electrical consumption.

 

[waterman5416]

You likely can also downsize the impeller to reduce the flow rate and electrical consumption.

Wow, If I could downsize impeller that would be the deal. Alot cheaper than new motor.
Thanks.

 

[Texas Splash]

Wow, If I could downsize impeller that would be the deal. Alot cheaper than new motor.
Thanks.

If you could get your hands on a 2-speed motor for that Power-Flo, it would really be a plus. Not only more flexible for you, but also significant energy savings. I run my pump on low 24/7. While VSPs are the thing today, there are still 2-speed motors out there, so it's an option.

WATERWAY SUPREME (or HAYWARD POWERFLO MATRIX) PUMP MOTOR REPLACEMENT

Here is my experience for changing the motor on a Waterway Supreme pump. The Hayward Powerflo Matrix pump is basically the same. In fact, that’s the item used in this InyoPools video example: NOTE: If you are swapping the entire pump assembly from Waterway to Hayward Powerflo or visa-versa...

www.troublefreepool.com

 

[JamesW]

I'm going to do some research on switching motors due to pressure.

Note that you cannot downsize the motor without downsizing the impeller.