Suction leak

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cstanton
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My Pool: 20 X 40 in ground gunite

Suction leak

Postby cstanton » Tue 24 Aug, 2010 08:40

I have air in the return jets of my pool. So far I have done the following.

1. Replaced the gasket and sealed the input line to the pump.
2. Replaced the pump lid gasket.
3. Replaced all of the seals in the two valves that control water flow from the skimmers and the drain.
4. Replaced and sealed the two drain plugs on the pump.

This phenomenon just appeared a few weeks ago. From what I have read; air in the return jets is an indication of a suction side leak which would include anything from the input side of the pump out to the pool as well as the pump drain plugs and the pump lid gasket. The water level is stable so I can safely say I do not have a water leak.

I tested setting the suction side valves as described below in an attempt to isolate the cause.

1. Drain only
2. Shallow Skimmer only
3. Deep Skimmer only

Neither of these improved or worsened the amount of bubbles I was seeing in the return jets.

I have read that another possible cause is the pump seal. Is this true or am I missing something else?


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mas985
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Suction leak

Postby mas985 » Tue 24 Aug, 2010 09:51

Pump shaft seals are on the pressure side of the pump so you would see water dripping out of the pump rather than air getting sucked in. A few things that can cause air in the returns.

Air in the pump basket would indicate a suction side leak but it sounds like you checked everything. But if you do have air in the pump basket, you probably still have the air leak.

No air in the pump basket and diminishing air in the returns over time could mean a spider gasket leak that allows air into the filter when the pump is off. Over time the air gets purged out and should diminish.

None of the above but you have a salt water chlorinator can also mean small hydrogen bubbles in the return.
Mark
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duraleigh
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Suction leak

Postby duraleigh » Tue 24 Aug, 2010 10:18

The most common cause is improper seating of the pump strainer basket lid....you seem to have addressed that.

Not a common source but a possibility is the drain plugs at the bottom of the pump strainer basket could be slightly loose and air would be sucked in there....are they tight?

Can you see air bubbles in the pump strainer basket?

Do the bubbles decrease in time or do they stay the same as long as the pump is running?
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Guest

Suction leak

Postby Guest » Tue 24 Aug, 2010 12:51

I can see bubbles in the strainer basket. They appear to come in from the suction line; however it is hard to tell for sure.

What is a spider gasket leak?

I keep asking myself "What would cause this to happen overnight?"
ChuckGeo
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Suction leak

Postby ChuckGeo » Tue 24 Aug, 2010 15:05

If the air is present in the same quantity no matter how you have the suction valves set, skimmer off or main drain off, it sounds like something in the suction manifold or suction side of the pump - lid gasket or drain plugs, or a crack in the pump housing. When you turn off the pump does water squirt out anywhere? If water squirts out somewhere at the suction side, that could be the location of the air leak. You might also direct a stream of water, garden hose, over the suction side, with the pump on, and see if the air bubbles in the pump stop when the water covers a certain area.
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duraleigh
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Location: Raleigh NC

Suction leak

Postby duraleigh » Tue 24 Aug, 2010 15:22

What is a spider gasket leak?.....not applicable since you can see bubbles in the strainer basket
I keep asking myself "What would cause this to happen overnight?"....don't know.


Did you check the drain plugs? If not there. then you must recheck every possible source for air to enter the line between the strainer basket and the skimmer.

Can you confirm the gasket is seated correctly on the strainer basket lid?
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floridapooltech
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Suction leak

Postby floridapooltech » Tue 24 Aug, 2010 18:35

It is possible the problem is underground with the suction side pipework. You may have a loose coupler or elbow fitting, or a crack in a pipe.
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cstanton
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Joined: Tue 24 Aug, 2010 08:33
My Pool: 20 X 40 in ground gunite

Suction leak

Postby cstanton » Wed 25 Aug, 2010 05:57

One thing I should mention is the amount of bubbles I see in the strainer basket is small. I can almost count them; however on the jet side I see a cyclical blast of bubbles coming out.

I am wondering if the pump is somehow damaged.

When I closed the pool last fall; I overpressurised the pump enough to crack the lid.

I replaced the pump lid and gasket in the spring and had no issues till this occured a few weeks ago.
floridapooltech
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Suction leak

Postby floridapooltech » Wed 25 Aug, 2010 10:50

cstanton wrote:One thing I should mention is the amount of bubbles I see in the strainer basket is small. I can almost count them; however on the jet side I see a cyclical blast of bubbles coming out.

I am wondering if the pump is somehow damaged.

When I closed the pool last fall; I overpressurised the pump enough to crack the lid.

I replaced the pump lid and gasket in the spring and had no issues till this occured a few weeks ago.



How much pressure are we talking, enough to crack a pipe or loosen a fitting?
Florida Pool Tech is a Florida certified service company headquartered in Tampa, Florida employing the best technicians and installers in the industry! Vist us at http://www.floridapooltech.com

Specializing in pool service and pool repair
cstanton
Pool Newbie
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Posts: 3
Joined: Tue 24 Aug, 2010 08:33
My Pool: 20 X 40 in ground gunite

Suction leak

Postby cstanton » Wed 25 Aug, 2010 11:29

Enough to crack the pump lid and send it flying into the air. The skimmers and drains were shut off at the valve; so nothing should have gotten by them.

I had the multiport valve in a position that bassically only allowed me to pressurize the pump.

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