dedicated vac line introducing air into system?

Limey

Well-known member
Jul 14, 2011
92
#1
Hi,

Quick question, my concrete pool has two jandy valves by the sand filter, one controls the water fall and the other controls the amount of suction for the skimmers and dedicated pool vac line.

Issue I have is that if I turn the jandy valve completely to dedicated vac suction line "power" ( open end or with vac connected ) the pool pump starts to lose prime and the pressure in the sand filter drops very low. Since owning this home, I found myself adjusting the said jandy valve to center area to allow skimmers to operate as well as the dedicated pool suction vac line.

Recently I bought a Pentair Kreepy Krauly and I would like to increase suction to it so that it can crawl the walls, but if I do, I then introduce air into the system.

Any ideas on what areas to look at?

My observations so far, two skimmers, the nearest skimmer has one open hole for skimming, the one further away has two hole, one is blocked by a cap of some sort. Also the main drain I think of my pool is also capped off , but cannot be 100% sure. I did recall the previous owner used to use his pool vac inside the skimmer, then I also recall wondering why he did this since he had a dedicated suction vac line. maybe there is a reason?

Thanks,
 

duraleigh

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#2
That suction leak is usually in the vacuum hose but there are other possibilities. Eliminate the hose first.
 
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Limey

Limey

Well-known member
Jul 14, 2011
92
#3
That suction leak is usually in the vacuum hose but there are other possibilities. Eliminate the hose first.
I had already eliminated the hose before the new hose and vac was installed. To eliminate I merely removed the complete vac including hose from the dedicated side vac pool line, making sure the spring loaded safetey cap was removed since it would close with no hose attached.
 

duraleigh

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#4
Well, that's confusing. I don't see how you could eliminate the new hose (as a leak source) unless you had it attached, pump running and completely submersed.

Did you read the article on suction side leaks in Pool School?
 
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Limey

Limey

Well-known member
Jul 14, 2011
92
#5
Well, that's confusing. I don't see how you could eliminate the new hose (as a leak source) unless you had it attached, pump running and completely submersed.

Did you read the article on suction side leaks in Pool School?
My terminology is probably newbie, with hose removed I was referring to the 38ft hose that the suction cleaner vac is connected to. I removed the hose from the dedicated pool side wall vac line. With dedicated vac line I'm referring to the flap on the side of the pool that sucks fingers off for breakfast [emoji2]

The symptoms per my first post persist with or without hose connected.

Side note , if one blocks a pool side wall vac line when in use what happens to the basket in the pump side, does no fill with air and lose prime ?

Sent from my SGP771 using Tapatalk
 

duraleigh

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#6
I think I got it now.

When you restrict the flow into the pump so it ONLY comes through the dedicated port, you lose prime, right?

If that is correct, that often is caused by the O-ring on top of the pump basket not being able to keep it's seal because of the increase vacuum inside the pump.

That's not always it but it's a cheap fix to replace the O-ring to see what happens.
 
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Limey

Limey

Well-known member
Jul 14, 2011
92
#7
I think I got it now.

When you restrict the flow into the pump so it ONLY comes through the dedicated port, you lose prime, right?

If that is correct, that often is caused by the O-ring on top of the pump basket not being able to keep it's seal because of the increase vacuum inside the pump.

That's not always it but it's a cheap fix to replace the O-ring to see what happens.
I've tried changing the basket O ring and used correct lube also. Still can't get all the bubbles to disappear from the basket. Looks like I have some sort of suction side leak somewhere.

I get more suction leak when turning the jandy valve to the direction that increases suction to the dedicated pool inline vac.
 
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Limey

Limey

Well-known member
Jul 14, 2011
92
#8
Replying to my own post. Also, if I turn the jandy valve between port vac line and skimmer quickly I can hear and feel something banging in the suction line , almost like a ball banging up and down the pipe. Probably water hammer?
 

kadavis

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Apr 5, 2015
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tucson, arizona
#9
Or there might be something in the line moving around and blocking the flow of water to the pump. You might also be ready to replace the o ring kit for that jandy valve
 
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Limey

Limey

Well-known member
Jul 14, 2011
92
#10
Or there might be something in the line moving around and blocking the flow of water to the pump. You might also be ready to replace the o ring kit for that jandy valve
The jandy valve was replaced last year, completely.
I'll try and take a video of this noise and post.