Troubleshooting Flow Issues

[Fgooga]

Hi Everyone,

I was vacuuming the old pool the other day, and noticed a significant loss of suction at one point. I went to check the pump and noticed it wasn't fully priming. Originally I assumed it was something that got into the skimmer line (I was vacuuming directly into the skimmer line like a dummy without using the skim vac) and there's a solid chance a dead frog or pecan or something got in the line. I tried flushing out the lines but that didn't seem to make a difference. I've gone through a few other tips like using a hose and checking to see if any of the suction side connects are sucking air in, replaced the pump gasket, took the thing off and cleaned out the impeller. One thing I've noticed that seems peculiar to me is that once I turn off the pump, water rushes from the filter back into the pool pump. To me, that would seem to indicate there is a buildup of air pressure at the top of the filter pushing that water back, but I've bled the filter and it still does that. I've also tried flushing the lines using a hose bladder, inserting it into the pump and flushing it back to the skimmer, using a tennis ball over the skimmer hole to alternately build up pressure then release. Pool shop is closed until the middle of next week with the holiday and I'd like to have it running for the holiday.

Any ideas?

 

[Texas Splash]

Welcome to TFP! Fiest thing I would recommend is that you update your signature with all of your pool and equipment info. You should also post some pics of your equipment pad so we can see everything there. It will help with replies. As for poor water flow, perhaps there is a partial clog. Even a suction side leak could do the same thing. Water rushing backwards when the pump is turned off is a sign that air is getting into the plumbing system somewhere. It could be an air relief valve, 3-way valve, just about anything. But once off air is seeping IN to a location that you can't visually detect because water may not spurt out. But tell us more about your pool & equipment in your signature and with some pics and we'll see what we can do to help.

also be sure to visit our Pool Care Basics page for lots of great info. Enjoy the forum.

 

[Bill1974]

I don't think a block in a suction line would cause the back flow unless there is trapped air in the filter. what was the last time the filter was cleaned/backwashed? Possible it plugged and also has trapped air and that is causing the back flow you are seeing. Or something in the pool equipment is not holding a vacuum and letting air in once the pump is turned off.

Is flow only bad when vacuuming? do you know what type of lines you have? rigid pvc or flexible? Possible that the flexible like collapsed if there was a stoppage in the vacuum line.

 

[Fgooga]

I've tried updating my signature a few times now but it keeps rejecting it saying it appears like spam? Not sure what's going on there. But the gist is that we have a ~27k gallon in-ground vinyl, with a 1.5hp super pump, and a sand filter. As to the types of lines, I'm assuming rigid pvc but I'm not sure. It's not just when vacuuming, whenever the pump is on I can see water pouring in but it does not get even 1/4th of the way up the pump basket. I tried backwashing the filter but that didn't make a difference. I'll try the filter deep clean I saw on the board tonight. Any other suggestions?

 

[Texas Splash]

I've tried updating my signature a few times now but it keeps rejecting it saying it appears like spam? Not sure what's going on there.

I was able to copy & paste that basic info into your signature. Maybe you can try to add more later. But some pics of your equipment pad might give us more to go on.

whenever the pump is on I can see water pouring in but it does not get even 1/4th of the way up the pump basket.

That sounds like a suction side leak.

 

[Fgooga]

I was able to copy & paste that basic info into your signature. Maybe you can try to add more later. But some pics of your equipment pad might give us more to go on.


That sounds like a suction side leak.

Here is an imgur album with some pictures and a video of it on filter and what happens when I turn it off

https://imgur.com/a/yhelpqj

 

[Bill1974]

Pressure test the suction lines and also pressure/vacuum test the pump by itself. Or plug the skimmer lines at the skimmers and fill the pump basket and see if the water level drops (make sure nothing is back flowing from the filter). If it drops you have a leak some where.

 

[Fgooga]

Pressure test the suction lines and also pressure/vacuum test the pump by itself. Or plug the skimmer lines at the skimmers and fill the pump basket and see if the water level drops (make sure nothing is back flowing from the filter). If it drops you have a leak some where.

I'll give that a shot again. I did that previously and didn't see anything obvious. I didn't get a chance to clear out the sand filter but backwashing didn't make a difference. I'll try your suggestion and the deep clean of the sand filter tonight. I guess I'm not sure how the sand filter would make this happen though, unless it's just having to work so hard to push the water through? I would think that would just result in a spike in pressure on the gauge.

 

[proavia]

When was the last time you cleaned and lubed the pump basket lid and o-ring?
Also, check the union coming out of the ground on the suction side of the pump. There should be an o-ring there too. Clean and lube that area. If either o-ring is bad, replace it.

You have a multiport valve. With pump off, put handle in "recirculate" and restart the pump. This will take the filter out of the equation temporarily.

Are you getting good flow from the return lines? Are there a lot of bubbles coming from the returns?

 

[Fgooga]

When was the last time you cleaned and lubed the pump basket lid and o-ring?
Also, check the union coming out of the ground on the suction side of the pump. There should be an o-ring there too. Clean and lube that area. If either o-ring is bad, replace it.

You have a multiport valve. With pump off, put handle in "recirculate" and restart the pump. This will take the filter out of the equation temporarily.

Are you getting good flow from the return lines? Are there a lot of bubbles coming from the returns?

The first thing I did was to order a new pump basket o-ring so that all just happened recently. I'll check the o-ring on the union coming out of the ground.

Flow from the return lines seems fine, there are bubbles but there's enough pressure coming out that I can see a fair amount of movement of the surface water near the returns

 

[proavia]

Clean and re-lube the o-rings and pump basket/lid mating surfaces.

Put the multiport in recirculate and report back if that changes anything. I doubt it will, as it appears you have a suction side air leak.

 

[Fgooga]

I'll give that a shot. I agree it seems like a suction side air leak, but the various methods I've come across on how to find it have turned up no obvious leaks. I'll report back later after I try your tips

 

[Fgooga]

Clean and re-lube the o-rings and pump basket/lid mating surfaces.

Put the multiport in recirculate and report back if that changes anything. I doubt it will, as it appears you have a suction side air leak.

Tried both of these suggestions. Putting the multiport in recirculate didn't change anything. I gave the o-ring and pump basket a quick clean-up and that didn't seem to change anything. I'm guessing next steps would be the pipe fittings leading up to the pump. I've tried running water over them for ~20 secs previously but that didn't change anything. I'll take another look tonight.

 

[duraleigh]

That's a suction side air leak......probably located at that union where the suction line comes out of the ground.

 

[proavia]

Is your water level in the pool about half way up the skimmer?
Is the weir door sticking or totally free without binding?
When the pump is running, is there a toilet bowl type vortex in the skimmer?

 

[Fgooga]

It's a bit over 1/2 way up. Pool doesn't have skimmer doors but I'm looking into adding them as I've now learned about them. There is slow rotation, I wouldn't necessarily call it a vortex

 

[proavia]

A weir door is important for proper skimming.
If there were a vortex it is sometimes because the water level is too low and it can suck in air thru the skimmer. That doesn't seem to be your issue.

Chances are there is a suction side leak between the skimmer and the pump. I would check that above ground union carefully for leaks.

 

[Fgooga]

Update - even though the pool level is about 1/2 way up skimmer when pump is off, after the pump is turned on the water level is low and is being sucked pretty aggressively into one of the skimmers.

 

[duraleigh]

after the pump is turned on the water level is low and is being sucked pretty aggressively into one of the skimmers.

That is likely the source of air. Raise the water level temporarily to the near top of the skimmer and see if the bubbling in the pump basket goes away. If it does, get a weir door and allow the water level to return to halfway up the skimmer throat.

If it continuers to bubble after you raise the water level. recheck that union proavia mentions.

 

[Fgooga]

Update - It was a pecan. After working through all the pipe fittings to check for an air leak, I flushed from the pump back to the skimmers again. Finally managed to free up a pecan and now the pump is working correctly.

thanks to everyone for the help. Skimmer weir doors are on the way. When we bought the place we had to put in a new liner and skimmer, and the pool guy took off the skimmer doors so I just assumed that was ok. Learning a bit more all the time.