priming and pump issues

Jump to latest Follow Reply
D

doncaruana

Gold Supporter
Bronze Supporter
LifeTime Supporter
Aug 25, 2011
586
Northville, Mi
Pool Size
15500
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Waiting for the pool builder to install some check valves but after some more reading on the topic, I'm starting to get a bit concerned.

My pump is about a 40-50ft run and 10ft higher than the pool. When it's running the basket looks mostly empty to me - maybe half full at best? (is this normal??)

But as soon as I turn it off, it will drop lose prime with a few minutes. I've had to set the speed on my intelliflo vs to around 3400 for 5 minutes for priming. When it comes on after sitting overnight, I get these big air bubble explosions as the returns pump out all the air.

Beyond my thinking that those air "bombs" are not a good idea for the system, I also started thinking that doesn't seem like something that should be happening anyway, even in this system. In my mind, this *should* be a closed system (or at least mostly so). It would seem to me that, even though the water lines are above the pool, the "act" of them running back into the pool should create some sort of vacuum unless there's a lot of air leak somewhere - kind of like putting my thumb over the straw when it's full of coke. The straw stays full until I let take my thumb off and let the air "in" the system.

The other problem is that one morning, I heard the VS running dry (and loudly!) after a half an hour. I thought these things had a priming alarm on them?? That was actually when I cranked up the priming speed set on it. But this worries me too because it runs "dry" a lot because of this - as much as 3-4 minutes, depending on how long the systems's been off.

So...all that having been said...am I way off base? Or does any of that make sense? And do I have a lot to worry about?
 
I know the height is an issue. And it does pull prime and pump, but I have to crank it way up to do it. But what I'm struggling with are these two things:
1) Seems like there's a significant air leak if it can throw that much air that fast. I just shut it off for 5 minutes and it took about 30 seconds to get water flow and pumped out a fair amount of air (not "bombs" but plenty - maybe 10 seconds of "furious" bubbles)
2) Shouldn't the VS be erroring out on pumping dry like that?
 
Actually, my first step was determining if my conclusion was even appropriate :) I mean, I'm still pretty dumb to all this stuff in honesty, so I wanted to throw out whether it even made sense that there was a leak. I mean, logically (to me at least), it seems that there is one. But given my lack of knowledge on all this, I might be way wrong and this is just to be expected.

So...does it sound like there is a leak? If so, besides the pump basket seal, where are other good candidates? The filter? If it was in the lines, wouldn't it leak water as well?
 
I gotcha' now. This pump and circulation stuff is not intuitive and it takes a little exposure to get a grip on it.

You have two sides to your circulatory system...the pressure side and the suction side. The suction side starts at your skimmer and goes to the pump's impeller. The pump "pulls" the water up to itself through this side.

From there, the water is pressurized or "pushed" by the pump up to the filter, through all the other devices and out to the pool.

If this system has absolutely no leaks, every device and pipe in the system will ALWAYS be full of water regardless of the pump running or not.

So, in your case, your pump apparently can generate enough power to suck the water up to the pump and it begins to push the water out. However, the suction side has a leak somewhere so air is being sucked in along with the water...hence the "bubbles traveling throughout your system. Then, when the pump is off, the water can find it's way back to the pool because that same air leak allows all the water above the water level of the pool to drain back to pool water level.


With the pump running - a suction side leak will always be air and a pressure side leak will always be water.

The most common culprit for suction side leaks is a poor seal at the pump basket lid. On a new pump like yours, that is less likely. Another source can be that the water inthe pool is not quite high enough and there is a "whirlpool" in your skimmer that allows air to be sicked in. Valves, badly connected joints, etc. are other possibilities. It will take some detective work. It is almost never the underground pipes.
 
Thanks a lot - great info and pretty much exactly what I was looking for! :)

Although the skimmer has whirlpooled at times, I have the same issue if I shut it off and just run the main drain, if I recall how I have tested with this.

When they built the pool (last fall) I told them I thought there was a leak (one really wet spot along the pipe run) and they said they pressure tested it fine and insisted there were no leaks. But, then again, I don't overly trust that everyone knows exactly what their doing. However, I don't think I have any actual water loss that's more than evaporation.

Again, trying to approach this with more logic than knowledge (gotta use the tools I got! :) ), it seems that the amount of air I have in the system in such a short time would be very unlikely to be coming from the underground pipes - a "passive" fill (when the pump is off) of that much air that quick I suspect would be difficult in packed earth. That being the case, it sounds like my most likely candidates are the valve right in front of the pump (that switches between skimmer and main drain) and pump lid. Even though it's new, I honestly don't trust that all the folks that worked on it were top notch.

Does all that make sense still? Are there any recommended ways to find suction side leaks (like soapy water for gas bubbles, for example)?
 
One common tactic is to run a garden hose over different pipe joints while watching the pump strainer basket. When you are running the garden hose over the leak the bubbles will disappear from the pump strainer basket. Shaving cream also works, shaving cream spread over a leak will be visibly sucked into the leak.
 
You guys are awesome! :)

I ran out and played with the pump a bit, standing right next to it. As soon as I turn the pump off, the strainer starts draining. After about 5 minutes, it starts gurgling a bit and tries to find some kind of equilibrium (strainer basket about 1/4 full or lower) with the filter (at least that's what I think is going on). But, more importantly, as soon as I turn it off, I start seeing big air bubbles coming in the inlet. That hazy semi circle at the bottom of the lid below is one of the air bubbles and in the 2nd pic, you can see where it broke up into several smaller bubbles.

Now while I was doing this, when I turned the pump off, something caught my eye. If you look at the 3rd pick below, you'll see a shot of water squirting out of the valve! Immediately after turning the pump off, this happens 2 or 3 times. Again, being unfamiliar with all this, my guess is that if this isn't my only problem, it's at least one of them. Interestingly enough, I found this post with apparently the same exact issue and these Jandy Neverlube valves are not supposed to leak!

So, between Jandy and the builder, I should be able to get a replacement for this valve. In the meantime, should I try tightening the screws in this? Or any other sort of "repair"? The valve *should* be less than a year old (unless they put some used ones on or something).

This has been nagging me and I'm glad I dug into it *before* they installed the check valves. I'm actually really irritated that guys that do this for a living wouldn't have picked up on this problem right away.

Now...with that sort of behind me...anyone have any thoughts on the VS? After reading other people's issues, I'm thinking I should be getting some kind of prime alarm. Or is it possible that it's not that the pump "loses prime", but that it has so much air it just doesn't pull enough water until I crank it way up and then it starts working. Again - not real knowledgeable here. :)



[attachment=2:xgtxseg9]air bubble1.jpg[/attachment:xgtxseg9]
[attachment=1:xgtxseg9]air bubble2.jpg[/attachment:xgtxseg9]

[attachment=0:xgtxseg9]valve leak.jpg[/attachment:xgtxseg9]
 

Attachments

  • air bubble1.jpg
    air bubble1.jpg
    110.5 KB · Views: 112
  • air bubble2.jpg
    air bubble2.jpg
    109 KB · Views: 112
  • valve leak.jpg
    valve leak.jpg
    110.9 KB · Views: 112

Enjoying this content?

Support TFP with a donation.

Give Support
Tightened them, but all it did is slow it down. (i think). This valve is new - would it likely be the gasket, this early? I can actually hear the air hissing into the valve now. Wish there was something I could put around it... Too bad the pool store is closed...
 
Chances are it is just a bit of debris stuck in the edge of the lid keeping it from sealing completely. I would take the top off the valve check that everything is clean, lube the seal with some silicone plumbers lube and put it together again. Odds are that will fix it.
 
Well, gentle folk, I can't thank you enough for all the help. I went on up to home depot and bought some of their "William H. Harvey Silicone Grease", mainly because it's completely non-toxic and it has no petroleum.

So, emboldened by all the great info I get here, I decided to crack open that Jandy Neverlube valve. I'd have to say that it was pretty clear what the problem was as soon as I got the cover off (see below)! Some silicone grease and 8 re-tightened screws later ...no more squirting out of the valve when the pump shuts off. And when I stopped the pump, I sat there and watched the water...do nothing!! It just stayed in the basket where it belonged! I also noticed no where near the swirling bubble mass as before when it was running, now I just have a big couple of bubbles at the top of the lid. Not sure if those are a big deal or not - do I need to worry about them?


[attachment=0:71asdtm9]O-ring not seated.jpg[/attachment:71asdtm9]
 

Attachments

  • O-ring not seated.jpg
    O-ring not seated.jpg
    184.3 KB · Views: 76
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply