Pentair SuperFlo VST Will Not Prime

[Animal827]

I will try to keep this short, but if any additional information, picture, or videos will help, please let me know. I will premise all this that I had a complete renovation of my pool last May 2023. Everything but the hole in the ground was replaced (pipes, skimmers, drains, pump, liner, etc.)

I opened for the season several weeks ago. During the pool opening, the "Pool Guys" had a hard time to get the pump to prime. I noticed a lot more air and chugging during this process. After an hour, they got it to prime and hold (albeit with a lot more air in the pump). I noticed that in order to keep the Pentair iChlor 30 happy, I had to run the pump at higher RPMs (last year I was getting away with 1800/2000, but now needed 2800).

I noticed a lot of air bubbles coming out of the returns, so I called the "Pool Guys" back, and they tightened a few things, and then everything was working perfectly (noticed no air bubbles in pump or returns and was able to run at 1800/2000 RPMs)...until midnight, where the air bubbles started again. During and after the Memorial Day weekend, I noticed that my pump would not have a prime. The first time, I just cleaned the basket in the pump, and then it went back to "working" (with the air bubbles). However, yesterday and today, I could not get the pump to prime. I have called the "Pool Guys", but, as you can imagine, they are busy, so they will not be here for several days. Note: the current "Pool Guys" are not the same company that renovated my backyard and pool.

I recently tried the water test to see if maybe it was the drain plug, a union or glue joints, or the pump lid, but no luck. Does anyone have any suggestions that I can try before the "Pool Guys" get here?

 

[PoolStored]

First line of offence. Remove the pump lid, remove the o-ring. Clean the pump lid area where the o-ring sits with alcohol. Dry lint free rag, clean the o-ring (no alcohol). Use Magic Lube II or other silicone lubricant (not sealant), don't use a teflon/PTFE based lube. Clean the top of the pump where the o-ring seats VERY well with rubbing alcohol/denatured alcohol. Make sure it is smooooooooth and clean. Remove and lubricate the o-rings on the pump drains.

Next line of offense is to lubricate the union and the oring on this cap.



Retest.

If that fails, second line is to get a new o-ring for the pump lid and drain plugs.

 

[Animal827]

First line of offence. Remove the pump lid, remove the o-ring. Clean the pump lid area where the o-ring sits with alcohol. Dry lint free rag, clean the o-ring (no alcohol). Use Magic Lube II or other silicone lubricant (not sealant), don't use a teflon/PTFE based lube. Clean the top of the pump where the o-ring seats VERY well with rubbing alcohol/denatured alcohol. Make sure it is smooooooooth and clean. Remove and lubricate the o-rings on the pump drains.

Next line of offense is to lubricate the union and the oring on this cap.

View attachment 578619View attachment 578620

Retest.

If that fails, second line is to get a new o-ring for the pump lid and drain plugs.

The O ring for the pump lid has been cleaned and lubed (I think Aladdin lube). I have been at this all day, and was able to get a prime after 15+ minutes on recirculate. I then quickly did a backwash and rinse. Then I quickly went back to filter. This baby was chugging along - primimng and hten losing it and then chugging to ge tit back...

That being said, once I was able to get my air bubble prime back - I redid the water test. When I ran water over the cap I did notice the pump basket had no air bubbles in it. I also saw the air bubble reduce when I ran over the 3 way valve, but that might have been spill over onto the cap. I went and tightened the cap and hear an air squeak noise. I decided to stop there before I break the pipe by over tightening.

Do you think this is enough to tell the "Pool Guys" to fix, or is this something that I should or can do?

 

[PoolStored]

If it stopped with water on the cap, I'd get a new o-ring on the cap and lube it. Pool store (pffft...I said that), or Ace hardware has o-rings. Take the old with you. Do you have a caliper? Measure your oring and match it. How o-rings are measured...

AS568 O-Ring Size Chart - Marco Rubber

Interactive standard o-ring size chart to find Parker and AS568 o-ring size dimensions. Order Online millions of o-ring sizes are in-stock

www.marcorubber.com

 

[Animal827]

If it stopped with water on the cap, I'd get a new o-ring on the cap and lube it. Pool store (pffft...I said that), or Ace hardware has o-rings. Take the old with you. Do you have a caliper? Measure your oring and match it. How o-rings are measured...

AS568 O-Ring Size Chart - Marco Rubber

Interactive standard o-ring size chart to find Parker and AS568 o-ring size dimensions. Order Online millions of o-ring sizes are in-stock

www.marcorubber.com

Thanks for all these quick responses! Not to sound more stupid than I already do, but I had to Google what a caliper was...and I definitely do not have that. To continue my stupidity, what precise steps would I need to follow before swapping out the O ring for the cap?

I will try to write them here:

1. Turn off pump
2. Set filter to waste
3. Take pump lid off
4. Untighten cap
5. Discard old O ring
6. Lube new O ring
7. Tighten cap
8. Put pump lid on
9. Set filter to filter
10. turn pump on
11. Observe and report

Is there a specific tool to tighten the cap or will anything sturdy that fits in between the gap work (that's what I used to tighten just now)?

 

[PoolStored]

Let's back up. Which cap did you put water on to get the pump to prime.
The cover on the pump or
this cap

 

[Animal827]

Let's back up. Which cap did you put water on to get the pump to prime.
The cover on the pump or
this cap
View attachment 578672

This cap

 

[PoolStored]

Let's try again.
Call the cap on the pump "LID"
Call the cap by the valve as "cap"

Water on the LID or CAP allowed the pump to prime?

 

[Animal827]

Let's try again.
Call the cap on the pump "LID"
Call the cap by the valve as "cap"

Water on the LID or CAP allowed the pump to prime?

When I put water on the cap (circled in red in photo) the air bubbles in the pump basket disappeared. When i put water over the 3 way valve (circled yellow in photo) the air bubbles reduced, but did not disappear), which makes me think it was just splashing on the cap.

In short, the cap by the valve. Thanks!

 

[PoolStored]

Go to pool store and/or ace hardware. Get a reasonable replacement 0-ring. Should be fairly snug to the cap, but not so tight you can't get it on. should be same diameter and size (thickness).

Turn the pump off.
Remove the cap
Take old oring off
clean the cap
lube and put new ring on
tighten
turn pump on

Is there a specific tool to tighten the cap or will anything sturdy that fits in between the gap work (that's what I used to tighten just now)?

Put a Screwdriver shaft horizontally between the two bumps on the cap.

 

[Animal827]

Go to pool store and/or ace hardware. Get a reasonable replacement 0-ring. Should be fairly snug to the cap, but not so tight you can't get it on. should be same diameter and size (thickness).

Turn the pump off.
Remove the cap
Take old oring off
clean the cap
lube and put new ring on
tighten
turn pump on


Put a Screwdriver shaft horizontally between the two bumps on the cap.

Perfect! I will report back...hopefully soon.

 

[Animal827]

Thanks again!

It was definitely that O Ring for the cap. A close up of the before picture of the cap can show the cracks in the O ring, which actually ended up being completely separated.
After replacing, I was also able to see significantly less bubbles in the pump basket.
Lastly, I was able to run the pump at 1,700 RPMs to make the iChlor happy (which I ultimately set at 1,800 for a buffer).

Funny thing is that Leslie's did not have the O Ring, but my local hardware store was able to hook me up. Less than $24 total after taxes:
~$22 for 5oz Magic Lube II at Leslie's
~$2 for the O Ring (Exterior Diameter: 1-1/2 inch; Interior Diameter: 1-1/4 inch?; Wall Thickness: 1/8 inch)

Now, the bubbles did not disappear completely, and after another water test it may be the O Ring for the pump lid. I noticed the "Pool Guys" used Magic Lube (the blue one), so maybe if I replace that O Ring I can get this baby to run below 1,700 RPMs .

Here is to another successful TFP troubleshooting chat !

 

[PoolStored]

I noticed the "Pool Guys" used Magic Lube (the blue one)

Who you gonna trust?

Oh, yeah...that's who...

Here is to another successful TFP troubleshooting chat !

 

[Animal827]

So I hate to bring this up again, but I have two pictures of an o ring based on thickness. One is 1/8 and the other is 3/16. I was wondering if their is an issue with either one.

I started getting air bubbles again, but much smaller than before and not enough to stop the pump prime. I was afraid the 1/8 was too thin, but now I think the the 3/16 is too thick.

That plug is a hayward plug. It is possibly SP-1022-C, though there is no model number inside this particular one. It seems to match the other Hayward plus I have on hand.

Everything is working fine, but that's how it was the last time I changed the o ring. This time I decided to change the o ring on the pump basket (of courses after cleaning with rubbing alcohol).