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Thread: Low Suction Through Vacuum Head

  1. #1
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    Low Suction Through Vacuum Head

    Greetings to all! I am an experienced, pool owner for 13 years, and completely self managed pool owner for the last 7 years, except for the installation of my DE filter in 2004 by someone else. I even installed my most existing motor in 2005. But this current issue has stumped me.

    Does anyone have suggestions for troubleshooting reduced suction through the vac head end of the hose?

    My pool pump, motor and filter appear to run normally without vac hose hooked up, i.e. normal swim operation. The skimmer appears to suck in floating leaves etc normally, the return jets are strong and release no air bubbles or air "fizz."

    Several months ago, I noticed my vac head suction pressure became weak. Years ago, if not more recently, the suction was so strong, you could see leaves and algae being sucked in outside the vac head. Not now.

    When the skimmer plate and vac head are all hooked up after I use a return jet to prime the hose, as I have always done back in the days when vac head suction was strong, the hose used to have water flowing out the end that I stuck up to the return jet. Now, with the old or new hose, it doesn't "overflow" with water out this end as it used to do.

    With the equipment hooked up and attempting to vac, the return jet nearest the pool pump, now typically lets out tons of tiny air bubbles that look like soft drink fizz. At first I thought it was DE.

    Here is what I have tried, all to no avail:

    1. backwashed DE filter - filter grid assembly is 7 years old
    2. removed DE filter, disassembled 7 long and 1 short grids, hosed down thoroughly, reassembled and recharged DE - baseline PSI used to be 1 PSI when it was new in 2004, now, even after full disassembly and cleaning, the baseline PSI is 8 PSI, just a hair less than right after backwash with no reassembly
    3. pulled pump basket, checked impeller for debris - none found
    4. replaced hose cuff on the end of the hose attached to the skimmer plate - there was a small tear that I previously had used Monster Tape to cover
    5. replaced entire vac hose with a brand new hose
    6. tried vac on WASTE setting to see if the filter itself is an issue
    7. tried vac on RECIRC setting to see if the filter itself is an issue - knowing on this setting any debris sucked up would be sent right back out the return jets

    Any reasonable suggestions are appreciated!

    Thank you!

    Todd
    Charlotte, NC

  2. #2
    Administrator JasonLion's Avatar
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    Re: Low Suction Through Vacuum Head

    If sounds like your DE filter grids are getting blocked. Going from a clean filter pressure of 1 to a clean pressure of 8 either means the psi gauge is shot or the grids are getting blocked up. I suggest soaking the grids overnight in a mixture of one cup of automatic dish washer detergent for every five gallons of water, rinse them off throughly and then but the filter back together and see what the clean pressure is. Your step 7 does suggest that the problem is not the filter, but the grids should probably be cleaned by now anyway.

    The best way to investigate further would be to try and trace back the air bubbles you see coming out of the returns. That air must be coming from somewhere before the pump impeller, ie somewhere between the vacuum head and the pump strainer basket. If you can put the entire vacuum hose completely underwater and there are still bubbles, then it isn't the hose. Then check the seal on the pump strainer basket. Also check the pump drain plugs. If none of that turns up anything you can start looking for an air leak in the suction side plumbing.
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  3. #3
    Mod Squad Bama Rambler's Avatar
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    Re: Low Suction Through Vacuum Head

    X2 what Jason said. Even a little bit of air in the system will severely reduce the total suction.

    What is the filter psi when the filter is set to recirc?
    Dave J. TFP Moderator
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    Re: Low Suction Through Vacuum Head

    What is the filter psi when the filter is set to recirc?
    The PSI when the filter is set to RECIRC and is cut out of the loop is zero, which is what I think it should be if no water is being sent to the filter?

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    Re: Low Suction Through Vacuum Head

    So a year later I am still trying to troubleshoot this issue. Low or no suction, only when trying to vacuum. Anybody know if CycoLac Ball Valves are prone to tiny leaks? My understanding is that a tiny leak won't show any effects during normal pool operation, but can during vacuuming.

    My CycloVac ball valves is over 20 years old, but appear in decent if not good shape. The handles always stay in the same position. There is one large ribbed ring that appears to be for turning, but is on so tight, that my 7 feet, 295 pounds can't make it budge. It is also too large to get my adjustable wrench on it. However, just inside this large round ribbed ring, is a smaller, hex shaped connector, you can put an adjustable wrench on it. I have turned it about a half turn. I don't want to keep turning it to the right, b/c I am not exactly sure if that tightens it or might make a possible tiny leak there worse.

  6. #6
    Mod Squad zea3's Avatar
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    Re: Low Suction Through Vacuum Head

    Did you try soaking the grids in dishwasher detergent and checking the seal on the pump strainer lid?
    You can check all the joints on the plumbing by trickling water over the joints while the pump is running to see if the water is getting sucked into the pipe joint.

    If you can post a picture of your plumbing and indicate which valve it is you are trying to turn that may help us answer your question.
    TFP Moderator
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  7. #7
    Senior Member stev32k's Avatar
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    Re: Low Suction Through Vacuum Head

    Quote Originally Posted by tdfuller
    So a year later I am still trying to troubleshoot this issue. Low or no suction, only when trying to vacuum. Anybody know if CycoLac Ball Valves are prone to tiny leaks? My understanding is that a tiny leak won't show any effects during normal pool operation, but can during vacuuming.

    My CycloVac ball valves is over 20 years old, but appear in decent if not good shape. The handles always stay in the same position. There is one large ribbed ring that appears to be for turning, but is on so tight, that my 7 feet, 295 pounds can't make it budge. It is also too large to get my adjustable wrench on it. However, just inside this large round ribbed ring, is a smaller, hex shaped connector, you can put an adjustable wrench on it. I have turned it about a half turn. I don't want to keep turning it to the right, b/c I am not exactly sure if that tightens it or might make a possible tiny leak there worse.

    Any ball valve can develop leaks over time. The ball gets scored from opening and closing when there is even tiny amounts of grit in the water. I don't know how your system is set up, but if pulling a vacuum depends on a tight ball valve I would change out the valve especially since it is so old. You could try applying a small amount of high vacuum grease to the ball, but that is about as much trouble as replacing the valve.
    20' x 40' IG with vinyl liner volume approx. 35,000 gal.1.5 H.P. main pump, Polaris 280 cleaner W/ 3/4 H.P. booster pump
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  8. #8
    Mod Squad Bama Rambler's Avatar
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    Re: Low Suction Through Vacuum Head

    As said, any valve can develop a leak around the stem. Post a pic of the valve and maybe someone will know how to tighten the packing if it's even possible.
    Dave J. TFP Moderator
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    You can stop SLAMing your pool when you pass the OCLT (You lose 1ppm or less FC overnight, & You have .5ppm CC's or less) & your water is clear.

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    Re: Low Suction Through Vacuum Head

    OK, I'll get a pic up here soon. Say, does anybody know if a motor or pump is getting too old can cause a slight air leak?

    I last changed out my motor 6 years ago. It is an Emerson ultra quiet. When the pump and motor re-starts every morning, it has not lost all of its prime overnight, but it has to take about 10-15 seconds to partially re-prime itself. Obviously, some air is getting the system. The pump "sounds" fine, and for the most part, the motor does too, but, I can a very tiny and soft "chatter" inside the motor. You can only hear it when you are standing by the motor. I wonder if this is a tell tell sign that the motor is starting to go, and if it needs to be replaced. And if that is true, if it is allowing a tiny amount of air in the system.

    I know from experience in 2006, the last time I replaced a motor, motors give initial subtle clues early that they are failing, then like mine in 2006, will start to smoke and make wicked noises when they finally give up the ghost. However, that motor got 8 years (98-2006).

  10. #10
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    Re: Low Suction Through Vacuum Head

    Any place there's an intrusion into the sealed system is a potential for an air leak. However, it's unlikely for the back of the impeller to suck air into the system. If you're absolutely sure you've ruled out all the common places for air to get into the system it may be time to start inspecting the suction plumbing.
    Dave J. TFP Moderator
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    You can stop SLAMing your pool when you pass the OCLT (You lose 1ppm or less FC overnight, & You have .5ppm CC's or less) & your water is clear.

  11. #11
    Senior Member stev32k's Avatar
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    Re: Low Suction Through Vacuum Head

    Did you replace the skimmer vacuum plate? The one time I had vacuum problems the rubber seal on the skimmer plate was torn and leaking.
    20' x 40' IG with vinyl liner volume approx. 35,000 gal.1.5 H.P. main pump, Polaris 280 cleaner W/ 3/4 H.P. booster pump
    Hayward sand filter, 3.14 sq ft, 62 gpm. Liquidator chlorine feeder. 1 micron final filter bags (home made and very effective)

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    Re: Low Suction Through Vacuum Head

    Hmmm.... No, never replaced the skimmer plate. My skimmer plate has never had a rubber seal on it. It is all plastic that just sits on top of the skimmer basket, under water.

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    Senior Member mas985's Avatar
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    Re: Low Suction Through Vacuum Head

    Quote Originally Posted by tdfuller
    OK, I'll get a pic up here soon. Say, does anybody know if a motor or pump is getting too old can cause a slight air leak?
    If the shaft seal fail, it could draw in air but it would also leak water when the pump is running. However, if you are losing prime when the pump is off but do not see air in the pump basket while the pump is on, it could be the spider gasket in the backwash valve. Sometimes, they will leak air when the pump is off but not water out when the pump is on. Probably has nothing to do with your vacuum problem though.

    As for the vacuum issue, one thing I don't understand was the following statement:
    2. removed DE filter, disassembled 7 long and 1 short grids, hosed down thoroughly, reassembled and recharged DE - baseline PSI used to be 1 PSI when it was new in 2004, now, even after full disassembly and cleaning, the baseline PSI is 8 PSI, just a hair less than right after backwash with no reassembly
    What is the pump model and is that running at full speed? The filter PSI seems way too low for normal operation at full speed.
    Mark
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    Re: Low Suction Through Vacuum Head

    #2 above refers to the DE filter grids - they were installed in 2004, replacing an old cartridge filter system. Initially, and for the first year or two, my DE filter ran a PSI of about 1, with the needle just above the resting point. As the filters got dirtied up, even with backwashing and hosing, the "baseline" PSI, meaning the starting pressure with pump running, just after a backwash and re-charge of DE steadily rose to about 8 PSI.

    After 7 years with the original grid assembly, I replaced all of the grids, just to eliminate this as a source of an issue for my low vac pressure problem. Also, the tips of a couple of my grids were broken, where they inserted in to the manifold, as a result of my placed the entire grid assembly on the lawn on its head to hose down the bottom (bad move). However, with ALL brand new grids installed by me in October 2011, not only did this not affect the low vac pressure problem, the baseline PSI, in fact the PSI when I first ran the motor/pump, right after install of the new grids, remained at about 8-9 PSI, no where back to the really low PSI of just over 0 when the DE filter was first installed. Back then, I had rock solid vac pressure.

    The pump I have is a Hayward Self-Priming Super Pump, the motor is an Emerson Ultra Quiet Efficient motor I installed in 2006.

  15. #15
    Senior Member mas985's Avatar
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    Re: Low Suction Through Vacuum Head

    No plumbing system with a pump at full speed should be anywhere near zero PSI so something was probably wrong with the filter gauge during the initial measurements. Unless of course you were performing the measurements at low speed. Even 8-9 PSI is low but is possible with a very low HP pump and very large pipes. BTW, which SuperPump model do you have and what is the size of your plumbing?
    Mark
    Hydraulics 101; Pump Ed 101; Pump and Pool Spreadsheets; Pump Run Time Study
    18'x36' 20k gallon plaster/gunite pool, 1/2 HP 2sp pump, Aqualogic PS8 SWCG, 420 sq-ft Cartridge Filter, 450 sq-ft EPDM Solar Panel, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater, ThePoolCleaner, DIY Acid Dosing

  16. #16
    Senior Member stev32k's Avatar
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    Re: Low Suction Through Vacuum Head

    Quote Originally Posted by tdfuller
    Hmmm.... No, never replaced the skimmer plate. My skimmer plate has never had a rubber seal on it. It is all plastic that just sits on top of the skimmer basket, under water.
    If the skimmer plate does not have a tight seal against the skimmer inlet and pulls water in from the skimmer cavity instead of the hose you won't have enough vacuum. If there is a tight seal between the plate in the skimmer inlet it will be very hard to pull the plate off when the pump is running - if the plate comes up easily or with just a little effort then it is not sealed. A new skimmer plate is only a few dollars and it might cure the problem.

    P.S. With the skimmer plate in position and the pump running the water in the skimmer cavity should be absolutely still with no movement at all. If there is movement it means at least some of the water is by-passing the hose and that will result in low vacuum.
    20' x 40' IG with vinyl liner volume approx. 35,000 gal.1.5 H.P. main pump, Polaris 280 cleaner W/ 3/4 H.P. booster pump
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    Re: Low Suction Through Vacuum Head

    Thanks for the tip. I always pull on the Hayward Skim-Vac, and it is "tight" to start with; I can't just pull it off. Then within 3-10 minutes of vacuuming, the vacuum is lost and the Skim-Vac comes loose. I am going to check the "stillness" of the water in the skimmer cavity.

  18. #18
    Senior Member stev32k's Avatar
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    Re: Low Suction Through Vacuum Head

    Are you getting all the air out and full flow though the vacuum hose before trying to vacuum? I have never found a good way to get the air out of the vacuum hose except putting the plate in place and starting the pump. The pump will suck water for a few minutes until air hits the skimmer then it looses prime, the skimmer plate comes loose, and air comes out of the skimmer. Then I have to put plate back on and wait while the pump primes itself again. That usually takes several minutes and sometimes I have to replace the plate a second or third time before I finally get full flow though the hose and enough vacuum to work with.
    20' x 40' IG with vinyl liner volume approx. 35,000 gal.1.5 H.P. main pump, Polaris 280 cleaner W/ 3/4 H.P. booster pump
    Hayward sand filter, 3.14 sq ft, 62 gpm. Liquidator chlorine feeder. 1 micron final filter bags (home made and very effective)

  19. #19
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    Re: Low Suction Through Vacuum Head

    I think so. The pool guy I used to have for several years showed me how to put one end of the hose up to a return jet to force water in and air out. With this method, the hose would get chocked full of water to the point of it flowing out of the end of the hose stuck up to the return jet. Now, the hose still gets full of water, but not chocked full, and, water no longer flows out of the end of the hose. That's another "little" clue that tells me something is amiss.....

    I will work on getting the exact model of the Hayward Super Pump when I get daylight. I have my operating instructions. Based on them, it says IS-2600X5-98 in the upper right corner. I must have the model SP-2600X5.

  20. #20
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    Re: Low Suction Through Vacuum Head

    Problem solved!!

    After 9 months of frustration, it turns out, it was just a bad connection with the cuff at the end of the hose to the hose itself - the end going in to the skimmer. Ironically, this was the first thing I troubleshot last May. At that time, I brought a brand new pool hose (which includes new cuffs) from Leslie's. This did nothing to solve the low vac pressure problem. So, I returned that hose, and bought a new cuff, as my hose had about a 1/2" tear in the end of the cuff that goes attaches to the Hayward Skim-Vac which in turn goes on the skimmer basket. It turns out, that the new hose also was allowing a tiny amount of air in to the cuff, breaking or reducing the vacuum seal.

    With the hose plugged directly in to the skimmer intake without the Hayward Skim-Vac, the cuff remains 100% below the water, eliminating any air leaks. Suction is awesome, and remains for the entirety of my 30-45 minute vacuum sessions.

    So, I will either continue to direct connect, or attempt to cleanup, reconnect, and reseal the new hose cuff with alot more silicon!

    It is funny, but for at least 5 years, my cuff never let air in at all.

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