Acid check valve plugging periodically on IntelliPH

Vegas Mike

Bronze Supporter
Mar 30, 2019
47
Las Vegas, NV
Suggestions to eliminate acid check-valve plugging? Have a Pentair IntelliPH acid dispenser with a tank-mounted Stenner pump. The Pentair 522513Z check valve plugs once a year with what looks like fine black plastic shavings. I see a very small amount of black debris in the acid tank, but seems too difficult to attempt cleaning the tank. The 522513Z check valve has an internal ball. Anyone have experience using a duckbill check valve on 32% muratic acid? Considering a Stenner UCDBINJ duckbill, which looks like it may be more resistant to plugging. Pressure ratings on the check valves are 26psi to 100psi, but I don't know how much pressure is required on the acid pump side to push acid thru. Seems high when I test the valve. Doesn't seem such high pressure is necessary since the check valve is installed downstream of the filter, just ahead of the SWG.
 
but seems too difficult to attempt cleaning the tank
Sorry, but your approach makes no sense to me. You're willing to change the affected part with another, not knowing if it'll solve the problem, or even work at all, when you've already identified what's wrong, but just don't want to fix it? It wouldn't be my approach.

When the tank is almost empty, disassemble the tank (it's eight bolts, I believe), and dump what's left. Rinse it out thoroughly, and be sure to clean and inspect the filter at the end of the intake tube. If that filter is missing, or damaged, replace it. Then thoroughly clean the top half of the IpH. Inspect both halves for anything that might be contributing to the debris. Then reassemble. There are no moving parts in the tank, so the debris might have been there since its manufacture.

The pump's tubes need periodic replacing. Do that if it's been more than two years. The injector also wears, so replace that, too, if it's old.

The IpH requires regular maintenance, including periodic replacing of the parts worn down by the acid. That's how I'd handle this issue. If you want to try re-engineering it to avoid that, I don't have any experience with that, so can't be of any help.
 
Thanks for your insight Dirk, and taking the time to help. Actually, discovered that the acid tank continually develops new debris. Maybe stuff falls in when I take off the lid, or plastic scrapes from the container edge each removal. So my initial statement that you could clean the tank once and for all seems incorrect.

Since I have to replace the injector anyway, was checking whether anyone else had experience with the duckbill-type injector for acid, which seemed to me less likely to plug. Indication the injector plugged is a sudden increase in pH. I remove the injector and confirm it is plugged using a spare Stenner pump (my winter chlorine pump), and also test the injector's replacement. After the new injector is installed, the pH returns to setpoint within a day. This proves to me that the plugged injector was at least the immediate cause of the problem. I find the fine, plastic-like shavings plugging the injector on the acid side.

But, you are right that I should clean the tank and especially verify the filter is clean and in place. How else could junk appear downstream if the filter is working? And maybe there are residual shavings from manufacture still lurking that get washed in with each acid addition. But I'll wait for winter when the acid fumes are attenuated -- 114F today.

Have been replacing the peristaltic pump tubes yearly. Good to hear I could do that every two years instead. Buying the replacement tube was initially problematic because of inaccurate Pentair documentation. The correct tube for my Pentair IntellipH "Blue" pump is a Stenner EC30C-x series, but I just bought the "Repair Kit for Intelliph OEM Pumps" Poolweb #522386.
 
Good to hear I could do that every two years instead.
Uh, you might not be able to count on that. Pentair advises annually. I went four years, and that was way too long, as mine was severely compromised by then. I came up with two years based on my usage, YMMV. Check it annually and replace as needed (is what I should have written). They'll get brittle and/or brown.

I don't know the particulate size that little filter is supposed to keep out, but it seems like it is not doing its job. But, of course, that's not the source of the problem.

FWIW, mine doesn't have those shavings, and yours shouldn't. I would consider your situation a manufacturing defect. Is your unit still under warranty? If so, get it replaced. If not, you'll have to go exploring to see if you can identify where the shavings are coming from.

I don't have any experience with duck bills, but I have completely disassembled a Pentair injector. I could see how it could get clogged up. It basically works like those old pool snorkel sets, where the ping-pong ball plugs up the snorkel when you would submerge. Except the Pentair injector's ball is moved by pressure, not gravity or displacement. If shavings collected in the wrong spot, they could keep the ball from moving. So you're on the right track in that regard.
 
In case anyone accesses this old thread, an update. The "debris" that plugged the Pentair 522513Z check valve was actually the rubber seal inside the valve that the ball seats against. Finally disassembled a failed unit. The rubber breaks down, and the ball gets stuck, blocking acid flow. Apparently Pentair has revised their specification, and the new check valve is a Pentair 521510 / Stenner UCDBINJ Injection Check Valve. However, the Stenner duckbill seems to restrict flow more because the acid pump does not quite keep up during SWG operation. No doubt I'll find out later what else I did incorrectly.
 
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Which is why those parts must be replaced periodically, as I explained two years ago. They're subjected to harsh acid, you can't expect the parts to last forever without replacement. It's not complicated.
 
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Discovered what I did wrong. The black poly tubing end at the acid tank top had a half-inch split (pictured), which was enough to reduce the acid flow by almost half. Cut off the split and reconnected, and seems acid back to normal, now 1.6mL/second pump time. To make sure changing check valves was not an issue, compared output of the original Pentair 522513Z acid check valve to the Stenner UCDBINJ Duckbill (Pentair 521510) that I now use. Got almost identical flow rates when tested using a separate Stenner pump. The Duckbill is much less expensive to maintain because the Santoprene DuckBill Internal Check Valve is $4 each.
 

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Pentair considers all the tubing as wear parts, too, and recommends regular replacing. If you got a split end, that's a hint. Time to replace the entire tube, not just cut off the end. I haven't replaced mine yet, but you remind me not to take those tubes for granted. Mine are probably about due. I don't know if this makes a difference, but in addition to every wire on my pad, I encase all my IntellipH tubing in split loom tubing. I figure the less UV on all that the better.

intellliph_motor.jpg

By the way, do as I say, not as I do. Here's a good example of me not following my own advice. Here's the pump tube I replaced! I'm not sure why it worked at all.

old iph tube.jpg
 
Here's another "pro" tip. I write with a Sharpie, on the inside of my EasyTouch door, things I will likely forget, or things the next owner will really appreciate:
- The gallons my pool holds.
- The date I last changed my filter cartridges.
- The date I last cleaned my filter cartridges.
- The dates I last replaced anything on my IntellipH.
- Any dates relating to SWG maintenance.
- Etc.

The last record wipes off with a little Goof Off, and the new record goes in place. I could keep these records in lots of other ways, but right there at the pad is where I most need them, and a service tech, or the next home owner, will find them, and find them very handy.
 
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Pentair recommends diluting MA to 15%, which i been using for 5 years now. I have a trick where i use magic lube around the rollers and tube. My iph is indoors so that helps too. Still using the same santoprene tube since new. My replacement is stored lubed up on a ziplock bag awaiting the moment.
 
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Pentair recommends diluting MA to 15%...
Absolutely! Thanks for reminding us Felipe. Running at Pentair's recommended acid concentration is a great way to reduce wear and tear on your IntellipH. I buy the 31% acid, dump it in the tank, then refill the jug with water and dump that in. I've never run "full strength."
 
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Regarding diluting concentrated acid, "Do as you oughta, add acid to water!" Issue is concentrated acid heats rapidly with small amounts water, or slowly added water. Think of hot oil and water. Seems you have done fine with your method Dirk, but a caution for others.

And I am seriously thinking how I could move the Intellichem controller and probes inside like Flying Tivo. Mine are on a south-facing wall, and the system reports peak temperatures over 120F. As a minimum, will be covering the sensor wires in sleeves ala Dirk.
 
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Regarding diluting concentrated acid, "Do as you oughta, add acid to water!" Issue is concentrated acid heats rapidly with small amounts water, or slowly added water. Think of hot oil and water. Seems you have done fine with your method Dirk, but a caution for others.
Thank you for adding this reminder. I should have. I've often quoted that very diddy. I used to add the water first, but the problem is, when I do, there is always acid in the tank anyway. And it required another container. So I started doing it the "wrong way," and it's been fine.

This has been debated before here. I always thought the acid into water had more to do with splashing. The theory is, when pouring acid into water, what splashes back is the water, not the acid. So pouring water into acid, you get acid splashes. I've also heard chemical reaction theories, too. I don't know what to believe.

I use the IntellipH "throat" as designed, it holds the entire jug, upside down, while it empties. So I just place it in and walk away, both with acid and water. So whatever is happening chemically, or mechanically, is not getting past the plastic jug blocking the opening for the few seconds I'm in the vicinity. That said, I did get splashed once getting the jug started. A freak thing. Hit me right in the face, of course. So I now I only handle acid wearing one of these, super cheap at big box stores:

Lincoln Electric Face Shield Polycarbonate Face Shield in Black | K4924-1


But again, I appreciate your reminder. I firmly believe you cannot be too careful with muriatic acid.
 
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