Hayward Multiport Valve (Top Mount) Leaking At Base With Sand Filter

Rocket50

Gold Supporter
Apr 29, 2016
73
Nashville, TN
Hey guys, my Hayward MPV Variflo XL is leaking at the base where it connects to the sand filter. It is a top mount. Started leaking gradually a few months ago. Tightened the screws a little and we were fine. Now it is a constant flow from the seam area on the sand filter.

I have taken off the MPV and replaced the O-ring and changed the sand while I was in there. This unit is only 1-1.5 years old. Tightened everything back down. No difference. Still leaking. Talked to my pool shop. Suggested pinched O-ring or possible crack in the clamps that hold the MPV to the filter base. I purchased new clamps and tried them. Also, no pinched O-ring that I could see. Reseated everything. Started up. No change.

Read a post on here from 2009 that had the same problem. Suggested loosening the screws and see what happens. Tried it. Now more leaks. Tightened screws gradually with pump running and leaks (multiple now) will not subside.

I did find seams on the MPV that could be the culprit. When the plastic was molded, the seams are very large in my opinion. I took my dremel and lightly sanded the seams down. Thought that might be the issue. Nothing changed.

I am considering caulking the fitting and then dealing with that whenever I need to get back in. Anybody have any suggestions before I caulk this #$$%%^&(^&$%#!
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
15,195
Evans, Georgia
I had the same problerm. I replaced the clamps and Oring, using PoolLube to moisten the seal. Still leaked. Found one article that mentioned turning the clamps a quarter turn and see if that helps. We tend to always line up the screws in front to be convenient, so turning might work? Try it.

Why did you change your sand? I *never* needs changing....a little cleaning every few years maybe, but we only suggest changing it when its been gummed up by odd unusual chemicals.

Maddie :flower:
 
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Rocket50

Gold Supporter
Apr 29, 2016
73
Nashville, TN
Why did you change your sand? I *never* needs changing....a little cleaning every few years maybe, but we only suggest changing it when its been gummed up by odd unusual chemicals.

Maddie :flower:
My water gets very dirty due to the patients. Just figured since I was gonna be in there, I might as well change it.
 

JamesW

TFP Expert
Mar 2, 2011
22,117
Those filters are known to crack or split at the seams. Check carefully for a crack or split in the seam or just below the clamp on the underside of the lip of the filter.

If it’s cracked, file a warranty claim for a new tank.


img_20190429_124522587-jpg.99210
 
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JamesW

TFP Expert
Mar 2, 2011
22,117
What is the filter pressure after backwash and what is the pressure where you backwash?
 

Rocket50

Gold Supporter
Apr 29, 2016
73
Nashville, TN
Those filters are known to crack or split at the seams. Check carefully for a crack or split in the seam or just below the clamp on the underside of the lip of the filter.

If it’s cracked, file a warranty claim for a new tank.


img_20190429_124522587-jpg.99210
Yep. That is what is going on. Had a stream spraying the wall this morning.
 

JamesW

TFP Expert
Mar 2, 2011
22,117
The plastic filters are known to fail, especially if used at more than 15 psi.

You can downsize the pump impeller to get below 15 psi to reduce the risk of splitting the seam. Below 10 psi is best.

What is the pump model number?

If you want to stay above 15 psi, I would go to a commercial filter.


If you want a different filter, I would suggest a cartridge filter in the 400 square foot range.
 

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Rocket50

Gold Supporter
Apr 29, 2016
73
Nashville, TN
The plastic filters are known to fail, especially if used at more than 15 psi.

You can downsize the pump impeller to get below 15 psi to reduce the risk of splitting the seam. Below 10 psi is best.

What is the pump model number?

If you want to stay above 15 psi, I would go to a commercial filter.


If you want a different filter, I would suggest a cartridge filter in the 400 square foot range.
I have a Pentair pump SF-N1-1 1/2AE/348024. 1 1/2 HP. This is a little different from a normal pool or hot tub though. It is attached to this. Canine Underwater Treadmills– Oasis Underwater Treadmill for dogs | H2O For Fitness
 

JamesW

TFP Expert
Mar 2, 2011
22,117
The pump is too big for the filter. If you want to keep the same pump because you need the flow, you should go to a filter that has at least 4.3 square feet of surface area.

The HCF230, 30" Fiberglass Sand Filter has 5 square feet.

You could go to a cartridge filter. If you want to go with a cartridge filter, I would go with one with at least 400 square feet of filtration area.

If you do a warranty claim, they will want to send you a new tank and that’s it. Maybe you can work out a deal where they give you a credit towards a different filter instead of replacing the current filter.
 
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Rocket50

Gold Supporter
Apr 29, 2016
73
Nashville, TN
The pump is too big for the filter. If you want to keep the same pump because you need the flow, you should go to a filter that has at least 4.3 square feet of surface area.

The HCF230, 30" Fiberglass Sand Filter has 5 square feet.

You could go to a cartridge filter. If you want to go with a cartridge filter, I would go with one with at least 400 square feet of filtration area.

If you do a warranty claim, they will want to send you a new tank and that’s it. Maybe you can work out a deal where they give you a credit towards a different filter instead of replacing the current filter.
I am very limited on space so unfortunately can't go very big. Really need a new location but that is another problem.
 

sktn77a

Gold Supporter
May 16, 2010
1,968
Chapel Hill, NC
Hayward had a problem with their tank manufacturing a couple of years ago (seam splitting). Yours may be one of them. My S244T tank is 25 years old and is still going strong (although I've been through 3 MPVs). I'd probably just request a warranty replacement and stick with it.
 
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JamesW

TFP Expert
Mar 2, 2011
22,117
Just had a guy out here from Hayward and he said these filters are pressure rated to 50 psi.
What is their opinion about why the tank split?

If all filters ran at 45 psi, I am pretty sure that more than 95% would fail within 3 years.

Real world results show that anything over 15 psi results in an unacceptable number of failed tanks.

Ask the Hayward person for actual test data on how well tanks hold up at 50 psi.

In my opinion/estimation based on limited data, anything over 30 psi will have a failure rate of at least 50% within 3 years although I don't have anything to substantiate that.
 
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Rocket50

Gold Supporter
Apr 29, 2016
73
Nashville, TN
What is their opinion about why the tank split?

If all filters ran at 45 psi, I am pretty sure that more than 95% would fail within 3 years.

Real world results show that anything over 15 psi results in an unacceptable number of failed tanks.

Ask the Hayward person for actual test data on how well tanks hold up at 50 psi.

In my opinion/estimation based on limited data, anything over 30 psi will have a failure rate of at least 50% within 3 years although I don't have anything to substantiate that.
No opinion given. Stated they will take the tank and test it.

Thank you for your information. Filing the warranty paperwork tomorrow.
 
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