Chasing down a suction leak

[BMFJules]

Hello all, been lurking a few months and now I have some questions! New home owner, purchased a home with a 30,000 gallon in ground vinyl liner pool. Trying to get ready for my first season with a pool, and figure out how my set up works.

Set up is an intelliflo vsf pump, Hayward De4820 filter, and a nature 2 fusion in ground chlorinator thing.

On initial run, pump did not want to pull prime without forcing water through the skimmer into the pump. I noticed my multiport valve was leaking, so I ordered and replaced that, was a Hayward sp710xr50. After replacing the multiport valve it was a little easier to pull prime, but would lose prime after about 20-30 mins and never regain it. Was able to get the basket to fill up by holding the key down on the multiport valve. Not rotating it, just depressing it.

So I tried a couple different things, one of which was turning the pump off, switching the multiport to backwash, and running the pump at 3450 rpm. I watched the sight glass run clean, and turned the pump off. When I turned the pump off I felt water spray my calf

Found a bell reducer that was able to blow apart on the skimmer line from the pressure change when turning the pump off with the filter in backwash. Cut that out and replaced it with pressure fittings, and pump will start up and prime on its own now, but, after about 5 hours of running at 3450, the pump basket is only about half full, so I’m guessing I still have a suction leak somewhere.

Any ideas on where I should go from here? At work now, but can respond with more info and some pics later as needed. Just trying to get the circulation system dialed in so I can start slamming.

 

[Texas Splash]

Welcome to TFP! Yes, it sounds like you still have a suction side leak. You also should never have to run your motor at the max rpm like that. How about posting some pics of your equipment pad? Let us see all the equipment from various angles so we can see all the lines, valves, etc.

 

[BMFJules]

Here’s some pics I snapped, the multi cyclone is currently bypassed since I’m adding media and backwashing once a day

 

[Texas Splash]

That's a lot of plumbing with lots of opportunities for a suction leak, or air leak anywhere for that matter. It will take patience and going through each area systematical a little at a time. Each joint, each union, 3-way valve, etc.

 

[reggiehammond]

One of the easiest ways to find a suction side air leak is using a water hose. Steady stream of water onto every fitting, union, drain plug etc. Once you hit the right spot, the air leak will be plugged and the pump pot will fill. It’s very noticeable.

Given your pump house is inside, not sure if everything can get wet. That plumbing is very… interesting. Good luck!
If you can’t use water, I’ve heard that shaving cream can be used. I’ve never done it myself, however.

 

[MITBeta]

Are you sure it's a suction leak and not a restriction in the filter?

 

[BMFJules]

One of the easiest ways to find a suction side air leak is using a water hose. Steady stream of water onto every fitting, union, drain plug etc. Once you hit the right spot, the air leak will be plugged and the pump pot will fill. It’s very noticeable.

Given your pump house is inside, not sure if everything can get wet. That plumbing is very… interesting. Good luck!
If you can’t use water, I’ve heard that shaving cream can be used. I’ve never done it myself, however.

Yeah I’ve noticed almost none of the fittings are pressure fittings. And most of the ones there are from replacing the multiport valve and the one suction leak I found. The owners we bought the house from said they rarely had to do maintenance.

And it’s a little pump house/shed that was built just for this equipment. They really went through a lot of trouble to phone it in on the plumbing.

I tried hosing the lid with no results, but none of the actual fittings yet.

Do you guys have an opinion of the multi cyclone pre filter, or the nature 2 chlorinator thing? I Can definitely clean this up and make it neater plumbing wise. And if I’m gonna have to test every joint along the way, I might as well eliminate non-useful stuff, and condense everything into as small a package as possible.

 

[BMFJules]

Are you sure it's a suction leak and not a restriction in the filter?

Good question! I am not. I know very little about the filter set up. I know it’s a Hayward de4820, I’ve backwashed it till the water runs clear (about 2-3 minutes), then I add 4 scoops of de filter powder to the skimmer as fast as it’ll take it.

I’m guessing it would be worth opening the filter and giving the grids/assembly a good cleaning? There are bottles of de filter cleaner that were left in the pump house.

 

[MITBeta]

You mention that you're trying to SLAM. I'm wouldn't be surprised if the problem is that your filter is clogging and reducing the flow dramatically as opposed to a suction leak.

You could try starting the SLAM with the MPV on recirc (I think that's right, I don't have one) and vacuum to waste a few times, and then when you have time to babysit the filter, do that.

 

[BMFJules]

You mention that you're trying to SLAM. I'm wouldn't be surprised if the problem is that your filter is clogging and reducing the flow dramatically as opposed to a suction leak.

You could try starting the SLAM with the MPV on recirc (I think that's right, I don't have one) and vacuum to waste a few times, and then when you have time to babysit the filter, do that.

I am inclined to believe this may be the issue. After a fresh backwash, it performs the way I feel it should the whole time, but I’m getting at most 5-6 hours without having to depress the MPV key to reprime the pump for a few hours, before having to do it again.

Also, when I decide to backwash, it’s because my return Jets pressure has reduced to almost nothing.

So maybe it’s drawing air from wherever it can, because it can’t push the water?

I think I know my project for the weekend.

Anyone familiar with the de4820 filters know when a good cleaning of the filter should do, vs needing new filter grids?

 

[MITBeta]

I would run your SLAM to completion and then disassemble and clean your grids thoroughly and reassemble. See what happens.

You're only adding back 80% of the full charge amount after each backwash, right?

 

[BMFJules]

I would run your SLAM to completion and then disassemble and clean your grids thoroughly and reassemble. See what happens.

You're only adding back 80% of the full charge amount after each backwash, right?

The install guide says when the grid is fresh, it takes 6 pounds of de, and when applying DE after a backwash, it takes 4 pounds. Im not adding 4 pounds by weight (this may be a issue on my end), previous home owner said that after a backwash I should add 4 scoops of de to recoat the filter, so I did some assuming and figured the scooper they left me held a pound at a time.

 

[BMFJules]

Figured I’d provide an update. Almost done slamming, just trying to get a good cya (Taylor is reading below 30, so im just socking a pound of stabilizer every few days till I get between 30 and 60.)

I think the issue came down to my filter just getting clogged up with algae and reducing flow. Now that the pool is blue and clear, my pressure reading is more consistent, the pump basket isn’t accumulating air, and I don’t have to babysit it.

Thanks for all the awesome articles and advice for new pool owners. Can’t say how happy I am I didn’t have to call a pool company.

 

[Texas Splash]

Quite a difference. Good job.