Best way to find a suction side leak

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doncaruana

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Aug 25, 2011
586
Northville, Mi
Pool Size
15500
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
I have a suction side leak that's either new or newly noticeable. I'm trying to figure out the best way to find it. When I crank the pump up to full RPM, it will fill the basket all but some bubbles right under the lid. There is more air than used to be, so I know something has gotten worse.

I don't think the lid on my pentair intelliflo pump will be real conducive to pouring water over it nor am I convinced that I would be able to notice the difference to be honest. The pipe joints won't be a good candidate either. So I need something that I can put on that will visibly show me a leak.

I've used shaving cream in the past for some joints. Is that the best choice? Or is there something that might work better? How about the lid - if I can't really get water at it, any other suggestions?
 
Generally suction side leaks occur at the pump basket o-ring or above ground fittings and couplings between equipment and plumbing. After you have checked all those, you can try a pressure test to try and locate leak.


68,000litre, IG vinyl, LorentzPS 600 Solar Pump & 1/2 HP Tristar, Sandfilter, Aquarite T-15 SWG
 
tlevy said:
Generally suction side leaks occur at the pump basket o-ring or above ground fittings and couplings between equipment and plumbing. After you have checked all those, you can try a pressure test to try and locate leak.


68,000litre, IG vinyl, LorentzPS 600 Solar Pump & 1/2 HP Tristar, Sandfilter, Aquarite T-15 SWG
Click to expand...

That's where I'm looking. What I'm wondering is what is the best thing to use to visually indicate a leak. Shaving cream...soapy water...?
 
I had the same issue this year. I could not figure out where it was. So, I began at the 2 plugs in my pump. I put some Hayward O-Ring lube on the two plugs and the suction side air leak disappeared. I am not sure that soapy water and shaving cream would have found the problem.
 
From my understanding, the strainer basket plug is the only one of the 2 that would give a suction side leak. I replaced the o ring and put some magic lube on it yesterday - no change. Replaced the pump lid o ring, cleaned everything, magic lube...no change.

Starting to think it's where the pipes come into the pump to be honest. Soapy water just does not work well - pipes are vertical and you can't get it underneath on ones that are horizontal. Got some shaving cream. We'll see how it goes.
 
doncaruana said:
From my understanding, the strainer basket plug is the only one of the 2 that would give a suction side leak. I replaced the o ring and put some magic lube on it yesterday - no change. Replaced the pump lid o ring, cleaned everything, magic lube...no change.

Starting to think it's where the pipes come into the pump to be honest. Soapy water just does not work well - pipes are vertical and you can't get it underneath on ones that are horizontal. Got some shaving cream. We'll see how it goes.
Click to expand...
That's a bit confusing. There are two drain plugs on most pumps located near the bottom of the strainer basket, one on each side.....they can both cause a suction leak. I am not sure which other one you are discussing???.

There is only one pipe going into the pump that can cause a suction leak.....it comes from the pool and is horizontal.

Something is mixed up. Got a pic?
 
duraleigh said:
That's a bit confusing. There are two drain plugs on most pumps located near the bottom of the strainer basket, one on each side.....they can both cause a suction leak. I am not sure which other one you are discussing???.

There is only one pipe going into the pump that can cause a suction leak.....it comes from the pool and is horizontal.

Something is mixed up. Got a pic?
Click to expand...

The pump setup is below. As far as the intelliflo, there's one plug right under the basket and one over more in the body. I replaced a pretty beat up oring on the one under the strainer basket, but not the other yet.

Another thought...when putting magic lube on - use a lot??


pump and valve.jpg


pump.jpg
 
I learn something in almost every thread. I didn't know that VS pump had that drain plug towards the back. That is certainly on the pressure side of the pump and wouldn't cause a suction leak. My apologies for doubting you.

I also see what you mean about your intake piping although the actual intake to the pump is horizontal.

Try this....pump running, take a length of roughly 1" PVC pipe about 4' long and use it as a makeshift "stethoscope". Hold one end of the pipe almost touching the joint or connection . Hold the other end to your ear to see if you can hear the air leaking in. That only works if the leak is pretty large but it sounds like yours might be.

I suppose you might be able to seal each joint one at a time with vaseline to see if that stops the air but I have never tried that and I have no idea it would work.
 

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duraleigh said:
My apologies for doubting you.
Click to expand...

You've probably already forgotten more than I'll ever know!! So don't even think about it!!

I replaced the pressure side plug o ring anyway. It was a little rough too. Put more magic lube on the pump lid o ring also. Pulled the drain plugs below the check valves and put new teflon tape on them - they were a little bare. At least it pulled prime today - it wouldn't yesterday.

I still get a lot of air bubbles coming through that see-through check valve. And the pump won't fill the basket unless I have both sides open, even if it's just partial on one. I still get a lot of air bubbles coming through that see-through check valve also. After I let it drop down to what's always been my norm of 2200 rpm, the basket had dropped almost an inch in about 15 minutes.

I've looked at every thing I can above ground - I just don't see anything. I think I'm going to raise the white flag and call a pool company. I'll pray they find something I missed above ground but I just can't find this thing and the progression is starting to concern me to be honest.
 
duraleigh said:
If you are seeing bubbles through that check valve, then at least a portion (or maybe all) your leak(s) is prior to that valve. Where does that pipe come from?
Click to expand...

That one is to the main drain. I've always had bubbles running through it to be honest-here's an old post of mine. I'm not sure they're much worse than they were. But the overall air leak is *way* worse this year.

I looked around all the places as before but didn't really find anything this time around.
 
after reading your older post regarding the addition of a plug below check valve, makes it the 1st red flag for me, expose the plug and smear silicone around it with the pump running, if it is a leak source the silicone with be drawn into it, and a noticeable reduction of air bubbles will result when looking at check valve, silicone is very useful when trying to find air leaks, apply it at the inlet fitting threaded into the front of the pump, this is another common area for air leaks, do this with pump running, the next weak link is the black 3-way valve in front of the pump, the shaft o-ring, (the handle attaches to the shaft) is under the cap with the 8 screws around it, these are leak areas potentially also, replacing the shaft/stem o-ring is always a good idea, and frequently overlooked as a leak source, very prone to wear over time from valve handle movement, and the least likely source are at glued pvc joints, while the pump is running i sometimes get a can of pvc cement and apply it around the pipe joint connections, if there are any leaks they will seal by drawing the cement into the joint, its unlikely the joints are even leaking, but there are times i do this and discover one that was leaking, using silicone or glue as i describe only works on air leaks, they will not seal a pressure leak (water leak)

The soapy water method would be most useful for finding a leak on a tire, which would be a pressure air leak, not a vacuum air leak.

this is a very thorough approach, you may find the leak right away, and improve everything dramatically, and wont feel it necessary to check any where else, if after applying silicone to the plug, you might notice all air bubbles gone, problem solved.
It also is common to have several leaks in different locations, that when discovered, eliminate the bubbles gradually,etc
 
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When you say "silicone", what are we talking about? I can't think of any silicone besides silicone caulk...

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Put some magic lube on the plugs under the check valves. Didn't really see any difference.

The one under the solid check valve is stripped it seems, so God only knows if it has any seal worth a whit, regardless of what I put on it.

Here's a question...when I pull those plugs under the check valves, there should be a vacuum in them right? Because there is. Although even in normal operation, that water recedes down that column pretty quickly. *sigh*
 
duraleigh said:
You have a plug under each check valve? What were they used for?
Click to expand...

I had a company close for me and they drilled the plugs to blow out the lines. It always seemed odd to me since the equipment pad there is 12 feet above normal water level. But I guess you need to blow the lines out regardless. I'd love to just patch them up for good, but I don't know how the lines would get blown out at closing otherwise.

- - - Updated - - -

Actually, as I think about it, it makes even less sense now... The closed one is the skimmer. The clear valve is the main drain in the bottom of the pool. The main line is never going to get blown out.

The skimmer - different story I suppose. Is there a smarter way than having that drain plug. For that matter - since the plug under the main drain line makes absolutely zero sense (or am I missing something?) what would be the best way to plug it up for good?
 

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