can't keep pump primed with Pentair rebel pool cleaner

[Wheelie]

Hello,

Got a Pentair rebel a few months ago and it's all been working fine. Noticed today it wasn't working. I backwashed the filter and it started up again and was fine. Then I turned it off to empty the skimmer basket in the pump and couldn't get it to work again.

The pump is working okay on its own although there are a few bubbles at the top. I tested the pressure on the pentair hose and it was fine. So I did another backwash and the pentair started working again. But the pump drops in pressure and will only stay half full.

Any ideas?
Thanks,
Keelie

 

[Texas Splash]

Sounds like you have a suction side air leak, so you're losing some suction pressure. Does your pool have a dedicated suction port for that Rebel, or do you plug it into the skimmer? I'd continue to check all the typical places where air could get into the system from the vacuum, skimmer, hoses, above ground lines and valve, all the way back to the pump itself. Don't forget to inspect that pump strainer basket lid O-ring and make sure it's secure and lubed with a silicone pool lube. You might have a drain plug on that pump as well that has a small O-ring. Anything else between the pool and the pump on the suction side.

 

[Wheelie]

Hello!

Thanks for your reply. The cleaner is plugged into the skimmer. I've been running the pump all week without the cleaner and it stays primed, although there are two bubbles floating at the top. Does this suggest a leak? Or does it mean the problem is the cleaner?

The pump strainer o-ring should be in good condition because we only replaced the pump last year. Will get some silicone pool lube though.

Thanks,
Keelie

 

[Texas Splash]

Since the pump seems to be doing well on its own, it's starting to sound as though the problem is related to the cleaner - maybe the hose? But yes, I would still lube that O-ring to be safe. Mine gets some fresh silicone 3-4 time a year.

 

[Wheelie]

I ran the hose with the pressure sensor thing (the thing that checks the pressure from the pump is okay, and it runs fine. So I can't see that the hose is an issue. Maybe the last bit of the hose and the actual cleaner?

 

[Dirk]

When I replaced my filter cartridges, my pump started losing prime. Took me a while to figure it out. The increased flow from a clean filter got my Rebel working so well that it was crawling up the side right up to the surface, where it sucked in enough air to stall the pump! I had to decrease my VS pump RPMs a bit to reduce flow during the cleaner cycle. If you don’t have a VS pump you’ll have to throttle down the flow some other way...

When you test the suction, is it indicating near or above the upper range of suggested suction?

 

[needsajet]

Just a couple things to check. With the cleaner running, you can work your way along the cleaner hose from one end to the other, lifting it up out of the water. If the hose itself is sucking air you should hear it. Also if it's connected to the skimmer via the skimmer throat, it can rub there and eventually rub through.

 

[Dirk]

Maybe the last bit of the hose and the actual cleaner?

Just a couple things to check. With the cleaner running, you can work your way along the cleaner hose from one end to the other, lifting it up out of the water. If the hose itself is sucking air you should hear it. Also if it's connected to the skimmer via the skimmer throat, it can rub there and eventually rub through.

It wouldn't be the last bit of the hose or the cleaner, nor would it be most of the rest of the hose. Those are all underwater! If there was a hole or a leak, it'd be sucking water not air, which would have no affect on the pump's prime.

Yes, it could be the portion of the hose that floats on the surface, but that's easy enough to test, as needsajet suggests. Or you can take the hose sections apart and swap the sections that are near the skimmer (the ones that sometimes float on the surface), with the sections that are normally submerged, to see if the problem goes away. Then you can troubleshoot to find the section with the hole. Or just lift the entire, full hose out of the water and lay it on the coping, and hold just the last few inches under the surface. If that works for a while, you'll know it's not any of the hose.

But I'm tellin' ya, the thing is coming out of the water. This happened right after the filter cleaning, right? It's hard to spot, because it happens fast. The cleaner won't gurgle and struggle at the surface for any length of time. The first gulp of air it gets it'll lose its suction to the wall and fall back down into the water, that's why it took me so long to figure this out, because I couldn't catch it doing it. It's fast, but still plenty of time to take in enough air to starve the pump.

If the suction is high (based on the vacuum's tester thingie), and maybe even if it isn't, and the problem is intermittent (like it runs for a while, then later the pump is dry), it's driving itself out of the water...

 

[duraleigh]

+1 what Dirk says.

 

[Wheelie]

The cleaner is not moving at all when I connect it. So, I'm pretty sure it's not air being sucked in from the surface. My pump is right next to the pool so I can see the cleaner when I turn on the pump. The pressure is fine and is adjustable at the end of the hose so I can adjust to give it midway pressure. I can't adjust the pump pressure -it's not a hugely powerful one though.

A lot of the hose sits on the surface and always has - is that not normal then? This would suggest I have an issue with the hose - although it's always been like this and the cleaner has worked fine the past 2 months.

- - - Updated - - -

I will test the hose to see if I can find any holes.

At the moment, the minute I turn the pump on with the cleaner attached, it starts losing prime. Is that because it already has air in? Yesterday, I backwashed the pool to see if I could get the cleaner running again and it still didn't work. How do I get any air out to get it restarted? I will also turn down the suction a bit just in case it is climbing out the pool.

 

[needsajet]

Yep, it's normal for the hose to float on the surface including when full of water. The weight of the cleaner pulls it down in an arc. So each join is an opportunity for air to come in, or if it's rubbed at the skimmer (but I think you mentioned yours is new).

When I connect mine, I push the hose, hand over hand, down into the water to fill the hose with water, before connecting it to the skimmer. If I don't, my pump will lose prime, but then eventually prime again, but it takes 3 or 4 minutes.

Sounds like time to work through it systematically. For example, get it running with the pump primed, and at your normal flow (filter clean, adapter/bypass adjusted the way you normally have it (e.g. 11-13 RPM on the cleaner wheel), so you know you're getting your normal flow. Then eliminate hose leaks by lifting it out of the water hand-over-hand and listening/watching for hose leaks as the source of the issue. Next eliminate or confirm the possibility that it's reaching the surface. To speed up testing of that, use your pool brush to coax the cleaner over to the bottom of the wall at a shallow spot and watch it climb a few times and see if it gets to the surface. Do this a dozen times or so.

If those aren't the problem, then it's also important to know that a cleaner increases the vacuum on the suction side, so that air leaks anywhere on the suction side of the pump can become more noticeable.

 

[needsajet]

You want the cleaner hose to be full of water before you connect it to the skimmer. My second paragraph above works, and some people prefer to hold it over a return jet and watch the bubbles come out at the cleaner end. Either way, getting the air out of the hose before connecting to the skimmer is a good thing to do.

 

[Wheelie]

Okay, so followed the above and filled the hose using the return jet. Checked for leaks, and then removed the cleaner just to quickly check the pressure. When I went to re-attach the cleaner, a wooden peg fell out...(toddler in the house)...so that might have been part of the problem! The cleaner is working again, it's not climbing out of the pool. But, the pump still doesn't stay fully primed, it works at half-mast as it were. To be fair, when we used to attach the manual vacuum it did the same thing and I assumed this was normal.

Does this suggest a problem at the suction side? And I'm guessing it's not the pump since this has been replaced and we've had the same thing with old and new.

 

[needsajet]

Even doing everything perfectly, some air always gets in when you attach a suction device, and that needs a little while to clear. A small amount of air in the pump strainer can last a fairly long time, i.e. hours or even overnight. So let's just get that bit straight. The cleaner was attached after filling the hose, and the Pump strainer would then be fairly full, probably some visible turbulence on top, but the water level would be somewhere around 10-50 mm (1/2" to 2") from the top. Is that about right? Did that stay the same, or did it increase or lessen after a while?

- - - Updated - - -

When I say "a while" - I mean an hour or so

 

[kadavis]

Are you using the regulator valve that came with the cleaner in the skimmer. You should adjust to get around 12 RPM on the wheels. If the pump is still losing prime you probably have a small air leak that is showing up because of the increased vacuum the cleaner is causing, or your pump hp is to large and is cavitating

 

[Wheelie]

The pump strainer was pretty much full to the top, just some turbulence as you said - some bubbles. I filled the cleaner hose using the return jet, then attached it to the pump via the skimmer, the pressure drops and the water flow drops to about half in the pump, and doesn't regain the entire time the pump is running - about 6 hours.

The cleaner has a pressure gauge that you can attach to the end of the hose to test the pressure so I used that - it holds the right amount of pressure according to the gauge.

What is a pump hp and what is cavitating?

 

[Dirk]

Just so we're all on the same page here... Are you referring to this thing?



And when you say "it holds the right amount of pressure:"

1. Does the Disk Indicator stay within the black rectangle, within Maximum and Minimum flow?
2. Are you testing when the pump is half full of air? Or when the pump is primed and running fine, with only a few bubbles just below the pump's strainer cover?

I think you should refer to this as your flow gauge (which is what it is), and "indicating the right amount of flow," unless you all want to call it something else. It's not really "pressure."

For what it's worth, I've never thought to use mine at the end of the hose. I first saw my pool guy use it at my vacuum port, without the hose ('course, he was an idiot). And to be honest, I've never read my Rebel's instructions. Hang on... OK, just did (they were still sealed in plastic!!) The gauge goes at the end of the hose. I wonder if the OP could do both, and if that would tell us anything?

The wooden toy was certainly a setback. It's hard enough to troubleshoot one problem at a time, right? But at least that one is behind you. And the notion that a suction leak might only reveal itself under increased suction is a tough one to figure out, too.

This is quite a mystery. In cases like this, I revert to my tried-n-true troubleshooting technique. Which is what we've all been suggesting of sorts, but maybe not systematically enough. You dismantle or otherwise eliminate everything you can, to get back to a "no problem" state. Then you add back one thing at a time, as much as possible, until the problem resurfaces. That last addition is usually the culprit. I say usually, becomes sometimes it's only a combination of things that causes the problem, but we'll cross that bridge.

I'd suggest you start over, now that you've corrected for the toy. You'll be tempted to skip steps, thinking "That can't be it." or "I've already done that." You shouldn't. And please read this suggestion in its entirety, before you start. ESPECIALLY THE LAST PARAGRAPH.

BEFORE EACH OF THESE STEPS, BE SAFE, TURN YOUR PUMP OFF, EACH AND EVERY TIME.

Take out of your pool system every component of your cleaner system. Every component. Will the pump function correctly for 24 hours, without losing prime? Then the problem is with, or related to, the cleaner system. (Again, I know you think you know that. "Just do the work.")

Put the flow gauge into the skimmer's port (if it fits, skip this step if not). Can you get the gauge to indicate proper flow without losing prime? (Doesn't need to for this part of the test.) I need some other TFP'ers help here? How long can the OP leave that gauge like that? Will that hurt the pump? Leave it for as long as is safe for your other equipment and see if you lose prime. Hours, if you can.

Then repeat that last step, adding in one component of your cleaner system at a time, in between the gauge and the skimmer port. Seriously. ONE AT A TIME! Starting with that adjuster valve thingie you mentioned (Pentair's Regulator Valve I presume). Adjust the valve for the proper flow rate. Observe the pump. Observe the gauge, again for as long as is safe for your other equipment.

Then the first section of hose, then the next, etc. Gauge always last in line.

Then replace the gauge with the cleaner. I'd suspend the cleaner somehow to keep it from roaming around. And test that.

Then finally let the cleaner go to run normally.

Keep track of the gauge reading for each trial. Observe the pump each time. Run each trial for "as long as is safe for your other equipment."

If one of these trials results in the pump prime issue, then replace that part. See if that solves the problem. If not, come on back with all your results. If you skip steps, or combine steps, or shorten durations between steps, to speed things along, you only increase the chance of missing what is causing the problem.

WARNING: This is how I'd do it, but BEFORE you attempt this yourself, I'd highly recommend you let others chime in to see if they see a flaw in my MO. You're dealing with some very powerful, very expensive equipment. I'd want at least a few more sets of eyes on this to make sure I haven't left something important out.

 

[needsajet]

That's a good approach right there. Mine is different, but yeh, you're going to have to work through it, that's for sure.

Mine is that I'd change each easy thing at least once and see if trouble goes away, so I would eliminate the pump strainer cover and pump drain plug as possible air suction leaks. also listen for any air sucking around pool valves.

 

[Dirk]

That's a good approach right there. Mine is different, but yeh, you're going to have to work through it, that's for sure.

Mine is that I'd change each easy thing at least once and see if trouble goes away, so I would eliminate the pump strainer cover and pump drain plug as possible air suction leaks. also listen for any air sucking around pool valves.

I think those are good avenues to explore, too. I was merely suggesting that Keelie might be jumping from one idea to another in hopes of finding a quick fix, which hasn't worked out so far for her, it seems. (And pardon me if Keelie is a man's name! I'm an ignorant American, after all!) I've described one path of troubleshooting that she can follow (or not). But I'm mainly recommending she start again and be more methodical about it. She could start at the pump, without the vacuum, sure. But I was starting with the vacuum first for two reasons: based on the symptoms it seems to be at the heart of the problem in one way or another, and because it's all above ground and very easy to disassemble and reassemble one piece at a time. If she finds the problem there, great. If not, then she would have ruled that out, and then can start on the considerably more challenging search through pumps and valves and underground pipes, or however that's done (she'll need more than my thoughts about it, because I've never had to trace a suction leak before).

needsajet, would you (or anyone here) happen to know if running the pump relatively high through the flow gauge for any length of time would put any undue strain on the pump, or the other plumbing? I just didn't want to suggest something that could cause more harm than good. My instinct is no, because I'm assuming the gauge is merely simulating the suction load of the vacuum, which can run safely for hours at a time. But I'm not dead sure about that. Anyone?

 

[needsajet]

What is a pump hp and what is cavitating?

There should be a name plate on the pump with some information. kadavis asked because if the pump is way oversized, that can cause additional problems. Pumps vary and some show HP (maybe 1.0 or 1.5). Also likely is something like P1 1800W / P2 1500W or something to that effect. Letting us know either might prove helpful.

Cavitating sounds a bit like pebbles rattling around inside the pipes and is caused by the pump's suction pulling air out of the water and making bubbles, but don't worry about that too much for now, at least until we hear the power of the pump (HP or watts, depending what's on the name plate).

Dirk, no problem with the method. As I said, it's a good method. Just offering alternatives based on the stage we're at with the problem.