Cannot keep bubbles out

wwhite0310

Well-known member
Jun 13, 2012
49
#1
I have backwashed my system many times to get it to start flowing, but as soon as I fully open my ball valve on my return line the flow drops to a trickle. I can leave it partially closed and the flow is ok..not perfect. I have an intex 2650 sand pump/filter hard pipped with 1 1/2' pvc. I replaced the plunger valves with ball valves. I have noticed a small drip right at the output of the return line. Is there a way of testing for air leaks? When I do get the flow going good and I turn off the pump to switch it to the timer the water in the skimmer goes way down to where I need to open the lid to let the air out again. I am just at wits end on this and I am driving my wife nuts..
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
20,322
San Dimas, CA (LA County)
#2
Sounds like the water level is too low.

When you have no restriction in the return, the flow is greater than the supply, and you suck air in. Check for low water and if there's a flapper in the skimmer, that it doesn't stick.
 

wwhite0310

Well-known member
Jun 13, 2012
49
#3
The inlet is full of water..through wall skimmer with pvc attached to the bottom to pump..I can close my return valve and the water will churn fine in the pump, I can open the valve on the return line partially and it will at least flow, but if I open the valve all the way it drops to where the water does not even come through the return and I have to turn off the pump, open the lid to release air and start it again and just hope that I don't open the valve too far or I have to start all over again.
 

wwhite0310

Well-known member
Jun 13, 2012
49
#4
Richard, I would be glad to talk to you as I am probably loosing something in translation on here. PM and I will give you my number if you want.
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
20,322
San Dimas, CA (LA County)
#5
Not tonight. Bed time here.

I still say your pump is pushing water out faster than it can suck it in. And eventually it empties itself and loses prime. See what happens if you stick a garden hose running full blast in the skimmer, right down the pipe.
 

wetchem

Well-known member
#9
Can you take a picture of how your pool is actually setup... would be helpfull...
Would be great to see the water/pool side of the skimmer so that we can see how the water level sits.
-
As for the water hose... stick in the the opening of the skimmer... turn the water on full blast... start the pump... open the valves... or is that open the valves and start the pump... :)
-wc
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
20,322
San Dimas, CA (LA County)
#12
I think I see a problem. The pipe coming out of the skimmer is smaller diameter than the return line to the pool. So your pump can push the water out easier than it can pull it in. A 1.5" pipe is 225% bigger than a 1" pipe.
 

wwhite0310

Well-known member
Jun 13, 2012
49
#13
that pipe is 1 1/4" that goes to a 1 1/2"...could it be making that big a difference? I have been looking at the adapter intex sells, but for 20 dollars and some of the reviews I have read scare me.
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
20,322
San Dimas, CA (LA County)
#14
wwhite0310 said:
that pipe is 1 1/4" that goes to a 1 1/2"...could it be making that big a difference? I have been looking at the adapter intex sells, but for 20 dollars and some of the reviews I have read scare me.
Crunch the numbers. Cross-section of the 1-1/4" pipe is only about 70% of the 1-1/2" pipe. And then there's also the fact that pumps push better than they pull.
 

wwhite0310

Well-known member
Jun 13, 2012
49
#15
So is it a matter of getting the input the same size as the output? I guess I thought since the skimmer is full of water that the pump was pulling enough water.
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,879
Silver Spring, MD
#16
It is extremely likely that you have an air leak somewhere on the suction side of the plumbing. Try running a garden hose on one connection at a time and see if the air in the pump strainer basket goes away when you are running water on a particular connection. If so, that connection is leaking.

The pipe size issue is an issue, but it wouldn't cause all of the symptoms described.
 

wetchem

Well-known member
#17
Try something simple...
If you can take the cover off the skimer while the pump is in operation, watch how the water is being taken into the line.
With the cross-area differential, you might be creating a vortex in the strainer body; thus, allowing the pump to suck air when the return is open all of the way.

I know that this will happen in the smaller waterbaths we have in the lab under certain conditions: I have a waterbath where the drain is on the bottom... it has 1/4" opening. The entire piping used to be 1/4". The pump burnt out, we changed it out with a new pump from the manufacture. The new pump was rated the same, just used 1/2" fittings.... so we used a 1/4" to 1/2" adaptor between the drain tubing and new pump. We upsized the remaining fittings and tubing (the return hole actually was a 1/4" fitting with gasket.. the 1/2" worked without modification). We were actually trying to reduce the force that the return had as it pushed the glass beakers around the waterbath which cause other issues!

The pump would hiccup... it loose prime, then prime, loose prime, prime... Strangest thing I'd ever seen... my lab manger at the time had never seen anything like it either and he'd been in labs 20 ot 30 years at that time. (always a warm fuzzy when the old timers scratch their heads... confirms that I'm not totally crazy... well, maybe)

What was happening was that the pump would pull a vortex, suck air, loose prime, then the water would back fill, and the whole thing cycle.

The manufacture had already solved the same problem for other customers. There were two solutions... the first was that we put a vortex breaker in the waterbath Vortex breaker). The second was that we replaced part of the return tubing with the 1/4".

The vortex breaker alone worked just fine; however, we weren't getting enough mixing in the bath; thus the second fix - what I found though was that I could take that vortex breaker out of the bottom drain after we reduced the return size. The return to the 1/4" tubing was also suggested by the manufacture; however, when explained why we went to the 1/2" opening, that is when they sent the vortex breaker.

-wc
 

Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
22,818
SouthWest Alabama
#18
It has to be a suction side leak. Check the gaskets and seals on that original pump. It would also be a good idea to replace that old pump with an adapter. That old pump creates a good bit of suction head, and provides more places for a leak.
 

wwhite0310

Well-known member
Jun 13, 2012
49
#20
I did some tests and when we open the return valve all the way it indeed creates a vortex in the skimmer, so for now we are keeping the valve partially closed. I will try the running water over the joints when we get back home.

Thanks for the tips. I will let you all know how it goes.