baffled - low flow

Hi! Happy to find this forum. I am new here and I've searched this forum and have found all sorts of good advice but unfortunately have so far had no success. Here's the problem: My pump turns on fine. It seemingly builds up pressure pretty good but is only sucking a little bit of water through. (I say the pressure seems fine because when I remove the basket lid, you can hear the pressure relieve - and it instantly sucks up the water sitting in the basket.) I'll run the pump for a while and only a little water comes through (I am going to waste here, so it must not be a filter problem-right?) When I turn off the pump, water swooshes back into the basket from the pressure side. (Could it be a blockage on down the line? that doesn't seem right since it would have to go through the strainer etc) Here is what I have done: I repiped all suction side piping, taped, lubed etc. I can't believe that theres any air coming in there. I dont have a snake but I did have a TV cable :) I could twist and turn to get through the underground pipe (from the skimmer to the pump) and it went through no problem. I even put some drain opener down there. *At one point while running the pump I heard a thump which sounded a lot like a clog moving from one position to another, but after opening all pipes leading to the pump, I found no clog. Bizarre. So then I thought maybe its the impeller on the pump. Well, I had that aprt and it is clean. I took member name WASTE's advice and reached in to the back of the pump with my 7/16 and turned it back and forth (was able to do so) but that didn't have any effect. Other details: the pressure gauge isn't moving - just sits at 5psi. I was vacuuming fine before the problem started. Then at one point after that the pump was 'surging' (psi would go up and down from 5 to 12 psi). Sorry for all the detail but I figured if I was going to get any help you should have as much detail as possible. Any ideas?

Difficult to get an idea as to what is happening here. Have to ask some questions.

1. Have you opened up the multiport valve to the filter to check for any blockage or problems there.

2. The surging you mentioned could be a problem with not having enough water in the pool, and the skimmer having a vortex in it sucking air.

Hope this helps.

Pat

Thanks for the reply. Yes, I have checked the multiport valve and there doesn't seem to be any problems there. I have it set to waste so that the (sand) filter is taken out of the equation. And there is plenty of water in the pool...it has all the signs of an air leak but I've repiped everything and don't see any water leakage or hear any air leakage when I shut off the pump. I'm really stumped. thx..

If you are getting air into the filter, i.e. you have to open the vent valve on top, then you have a suction- side leak.

Check the O-ring to the pump basket has Magic Lube, or similar.

Check with a 3 - 4' piece of PVC pipe held against one ear, the other at different places on the suction piping. When you hear bubbles, that's where the leak is.

Hope this helps.

Pat

thx Pat. I went out and opened the top valve on the filter and air did escape. Even though I am going to waste, does this mean that there is def. an air leak problem on the suction side? Should I leave this open when going to waste? closed? does it matter? sorry - i'm trying everything here. I have already checked the oring around the basket (several times) and it seems ok. And I don't hear anything on the suction side as far as leaking or bubbles when I turn the pump off. ...and the reading on the presure gauge just sits at 4-5 psi -does this mean anything? thanks again...

You need to set the multiflow valve to go through the filter to check for air infiltration, when the pump has been running a good 1/2 hour. If you get a lot of air from the filter vent, i.e. more than a couple of seconds, then you have an air leak, and check as before with the pump running.

If not then you need to check the pressure side of the pump to the filter. Also you may need a new gauge. Remove it, and if there is pressure from the connection, and the gauge drops back to zero, then the gauge is alright.

You mention a back flow when the pump is shut off. Are there any valves downstream of the filter that might be closed or restricted? That could account for the back flow as the filter depressurerizes back through the pump. This also could account for an air-leak on the suction side, as this air pressure is driving the flow back from the filter.

Hope this helps some more.

Pat.

Rick,

does your pump and filter sit above the water level of the pool? Your description sure sounds like it. If so, are you giving the pump enough time to prime?

I may take as much as 2-4 minutes. If you are above pool level, post back and I'll give you some tips.

hi dave - thanks. yes - it does sit above the pool. i do give it quite a while to build up pressure but this time i'm not getting anything more than a very low flow of water coming through. at this point, i've taken everything apart and put it back together again. the frustrating part is that it was working when I first fired her up. I vaccumed for a bit (opening pool) and lost pressure about half way through the clean up. I didnt have a whole lot of crud in the strainer but I did empty nit a couple times. My gut says its an airleak on the suction side but I'll be darned if I can find/fix it...

Rick, can you turn off the suction line leading into the pump?

If so, try this.

Plan A

Turn off that suction line...completely

Put multiport valve in the filter position

Open the pump basket...there should be no water flow either direction.

Next, get a 5 gallon bucket and fill the pump basket 'til it overflows. I know some will go into the suction line...that's what I want.

Now, replace the basket lid and turn the pump on...keep the valve closed...you won't hurt the pump.

Most of the water should stay in the basket, since the pump can't suck it out because you've got the line closed.

Now, slowly open that suction line. It'll slosh around in the basket a good bit but, but hope fully, it will start to draw a larger and larger volume of water 'til it primes. It'll happen very quickly once it primes.

Plan B. If that fails to prime after a minute or so or you dont see an ever increasing flow of water into the pump, close the suction line again...pump running....it wont hurt it.

Next, Repeat Plan A above.....if it doesn't prime then, I am waaay off base.

thanks. ok - i did exactly as you said. first of all, the only way I can shut the suctions ide off is plugging the inlet hole at the base of the 'skimmer hole' - I did that, turned the multiport to filter and all the water in the basket rushed out - attempting to go toward the filter. I shut down the pump and all the water gushes back into the basket to the previous level. I tried it all oveer again - this time letting the pump run for a couple minutes, but same thing happens...low flow...and gauge reads about 4 psi...

Hi, Rick,

Sorry I couldn't respond...out for the evening.

First, I am assuming you filled the pump basket to overflowing after you plugged the skimmer...you don't say that but I'm assuming you did.

So, if you plugged the skimmer hole and filled the pump basket (and the suction line) with water, there is no air left on the suction side. Right?

Then, when you turn on the pump, all the water rushes out of the pump basket. That means it is replaced by air. In a working system, what should happen is nothing....the water can't rush out of the pump basket cause the air can't get in to replace it.

My next thought would be to fill up the entire suction side with water again, turn the pump on as before, then shut the pump off never opening the skimmer hole. If all the water is pumped out of the basket, It shouldn't refill into the basket because now the water (on the pressure side) cannot push the air back out. Make sense?

Rick, I'm stumped. Poconos always has good insight into this type of issue...maybe he'll come along with a good idea.

Hi. I really didn't expect much in replies since most everyone hopefully are ENJOYING thier pools this weekend :). Yes, I did everything you said but the water still moves out-then gushes back in...Would the fact that thw vari-flo has a cracked plastic o-ring (just under the handle) have anyting to do with this problem (it was cracked last year too but never had any probs) Might it be the pump?

Rick, met you over on another thread, it certainly sounds like an air leak on the suction side. If you bring a hose over to the filter pad and have it run a slow stream, you can direct the stream at any questionable connections or the valve itself (if your hose won't reach, you can use a bucket of water, slowly poured, to do the same thing). You used the words 'vari-flo' which indicates to me that you have a Hayward SP 733 valve (3 way). This would explain the problem - those valves are ^%#$&&$%&&$#$ !!!!. As I understand they have been or are being discontinued, they suck! (air mostly). If I'm right, you need SP 733Z1 for the replacement o-ring (if you can't get one, I can get it for you - in fact I have a couple in my basement, you don't mind that they've been through the laundry?)

Hey, Ted,

Man, I sure am glad to see you on this thread...I cannot figure this out! That Hayward SP 733 I assumed was his multiport. Duh!

That said, you think he has that valve on the suction side? Why would he have to go to the skimmer to shut off the water from the pool?

It DOES sound like a suction side leak but he's done his homework reasonably well.....I'm surprised he hasn't found it ....if it's there.

See ya' :)

Dave, if there is a 733 involved, I'll wager that it's the cause. Those valves are just a poor design(they had the right idea, but the gaskets and shell fail way too early. IMHO - Hayward makes the best pool equipment on the market, but they've had a few wrong numbers!

Hi guys. Thanks very much for trying to help me out. The vari-flo I have is an SP-710. I noticed that the 'non-metallic bearing cover' (as it is called on the instruction sheet I have for it is broken and just about completely gone. Might this be causing the problem? I'm nearing wits end but am adamant to fix this as it has become my personal challenge. Is there any other info can I provide that would help the troubleshooting process? Thanks again. Rick

Hi, Rick,

Is that valve on the suction side?

Hi. No. My setup is: from the skimmer a direct line (underground) and then up through the ground into the pump. The water goes through the pump to the valve where i have the option of filter, waste, recirc, backwash, rinse or closed. I am assuming suction side is anything before the pump...thx

Hi, Rick,

That's what I thought, and, yes, suction side is, logically, everything from the impeller of the pump back to the skimmer. Pressure side is everything the other way...pump up to the filter, thru the multi-port valve, etc.

So that Sp 711 valve is not the issue nor is anything on the pressure side since a pressure side leak is water spewing (leaking) from the system.

Suction side leaks, like yours, are characterized by air being drawn into the system. Okay, you've got a suction side leak and there are no moving parts on the suction side. The most common leak is at the o-ring on the pump basket. I know you said you've got suction at that basket but check the o-ring carefully again. Make sure it is seated correctly and eliminate it as a possible source.

The next most likely would be the union between the suction side pipe and the pump basket. There is typically an o-ring there as well. Ensure that it is in place.

I'm still stumped, but it sounds like it is getting narrowed down. An underground suction leak is always thought of but that is very unlikely. That system is drawing air somewhere betweem the skimmer and the impeller on the pump....we'll (you'll) find it. :)

Thanks for the reassurance. My gut all along was that it is an air leak somewhere on the suction side but I'll be damned if i can find it. I don't see or hear anything. I can see through the basket lid and the oring certainly looks sealed but to be sure, I'll get a new one. I don't recall an oring at the union of the basket and suction side pipe. I'll look at that again too. thanks - hopefully I'll be back with good news sooner than later.

Rick,

There is a drain plug at the bottom of most pump baskets. Is that tight?

must be reading my mind. I'll check those out too (yes, I have two of them down at the bottom). Also - I assume I should check the diffuser gasket as well since it comes right before the impeller? anythig else in that area I should check while I'm 'in there'? thx...

Rick,

I don't know what the diffuser gasket is. If it's in the pump, I would say no need......seems to me anything in the pump would spew water rather than suck air.....I could be wrong on that, tho.

here's a pic of the pump I have:
http://www.poolcenter.com/parts_pump..._superpump.htm
You'll see that (#3) is the diffuser gasket. I'm thinking I should probably check that too...but I'll check everything else first---just want to be thorough...I'll be back later with my (hopeful) progress

Hi Rick and all. Just wanted to apologise for the confusion with the 733, I had a senior moment and confused 'direct a flo' with 'vari flo' ;( ). Rick, can you see air bubbles in the pump, if not you don't have a suction side air leak - also if you do, how big is the air pocket visible in the lid? (size gives an indication as to the severity of the problem). Good luck with your detective work, hopefully tomorow, you'll post in telling us the problem is solved.

I *think* I foudn the problem - or at least a large part of it. BOTH drain plugs WILL NOT TIGHTEN (ugh) It appears that the inside threads are worn. So it's not as easy as simply replacing the plugs. So I guess that means buying a whole new basket/configuration? yuck. Then it dawned on me, if I'm considering trashing the existing unit, why not first try to seal the drain plugs somehow - even if it is a permanent bond of some sort at least it would get me through the summer. any suggesitons/ideas? I suppose pvc glue would work but I wonder if something less permanent might work...hmm...btw: i did try threading the plugs with tape and when I did that I did see a slight increase in pressure - and the pump is surging again. so that must be it...i hope

Rick, I think you're on the right track, many problems that I've had to address have been the result of a few small leaks, rather than just 1 big one. Before you go gluing anything in, see if you can find a replacement plug that comes with a gasket, (SP 1700 FG, Hayward, should do the job). There is also the posibility that the pump housing itself has failed, if that's the case, glue the 'bejesus' out of the plugs and cross your fingers that the glue hits the right spot.

thanks. yep - i tried plugs with gaskets but they still spun. I went ahead and glued the drain plugs in - it got better (enough that I can open the pool now -yay!) but its still not 100%. I noticed one of the plugs dripping water so I'll need to hit it with the glue again. Looks like I'm on the way. Thanks to everyone for their help - hopefully my wife will stop calling the pool my mistress now :)

Rick, as you have already glued the plugs in, try some 2 part epoxy to seal the leaks. Glad that you've almost conquered the problem!!!

The epoxy must've took care of the last of the leak as I now have 100% flow! In fact, it's better now that it's ever been. yay! Thanks to all of you for your help! Best, Rick

Rick, that's why were all here. This forum allows us to help and guide each other towards the 'Pool Solution' for any given problem. Congrats on conquering your problem!!