System loses prime when attempting to vacuum from skimmer closest to pump

[jgold723]

Not a newbie, but I have a problem that has stumped me for several years. I have a 16 x32 inground pool. Two skimmers. 1 hp hayward pump. Hayward S200 sand filter.

Ever since buying the house and inheriting the pool, I have been unable to connect my vacuum hose to the skimmer closest to the pump. Doing this causes the system to lose prime within about 30 seconds and the hose disconnects from the skimmer.

I am able to vacuum from the skimmer that is farthest away. It works, but the suction isn't as good and vacuuming takes forever.

Some more details:
>>No visible bubbles coming out the jets;
>>I prime the hose before connecting it to the skimmer using the vac plate;
>>I move the selector switch to "Full" for the skimmer I'm using;
>>The correct end of the hose is connected to the vac head;
>>I bought a new vac head

Any ideas as to what might be happening?

Thanks,

John

 

[bobodaclown]

Hello John,
Does the skimmer work normally without the hose attached? Are you priming the hose (taking the air out of it, prior to connecting)? Is there a valve to select the skimmers or to isolate the skimmer? It's getting enough air from someplace to lose prime. that's the trick to figure out.

 

[jgold723]

Hello John,
Does the skimmer work normally without the hose attached? Are you priming the hose (taking the air out of it, prior to connecting)? Is there a valve to select the skimmers or to isolate the skimmer? It's getting enough air from someplace to lose prime. that's the trick to figure out.

Thanks for the tip. Both skimmers work and I am priming the hose. There is a selector switch which I set to whichever skimmer I'm connecting the vacuum hose to.

Ironically, there is an air leak on the skimmer line farthest from the pump (skimmer2), but this is also the skimmer which actually works for cleaning. If I set the selector to the skimmer closest to the pump (skimmer1) and use that one (skimmer1) for cleaning, I experience the loss of prime.

Is is possible that the system is sucking air from the skimmer2 side even if I have the selector set to skimmer1?

 

[bobodaclown]

Does it suck air slowly or pretty quick when it looses prime?

 

[jgold723]

Does it suck air slowly or pretty quick when it looses prime?

I'm not sure about air consumption, because I'm too far away from the valve to notice. But it does lose prime pretty quickly - -usually within 30 seconds to a minute.

 

[Davejavu]

Here's my guess...When you restrict flow with the vacuum closest to the pump, then the other skimmer sucks much harder. If there is an air leak in the far skimmer, then the pump is sucking harder so more air gets sucked in. As a side note, with the vacuum in the farther skimmer, the resistance of the extra piping will somewhat slow the water flow. So the effect of the vacuum on the far skimmer will be less than on the closest skimmer.

 

[skimmerswimmer]

You may want to check a few things to see if you have the same issue as me. I have a 1 HP pump as well but I have a separate vacuum line on one valve, two skimmer lines on another valve and the drain line on a third valve. I use a 40' vacuum hose in line with a leaf catcher before entering the vacuum port. Due to the water restriction through the hose and leaf catcher, I find that I have to mix in some water from the skimmer or drain lines when vacuuming otherwise I start to pull air and the pump can lose prime. You start to see the bubbles entering the pump and this is when you need to open one of the other valves a little bit until the air in the pump basket goes away. Although having one of the other values open a little reduces the vacuum effectiveness, it still works fine.