Skimmer Diverter/Main Drain Questions

[DanF]

Hi,

Attached are pics of my skimmer, plumbing to filter pump, main drains, and a diverter that sits beneath the skimmer basket.

I am wondering whether I need the diverter at all. When I pull the diverter out of the skimmer well, I feel no suction from the front (weir-side) hole, but PLENTY of suction from the rear hole.
I am not using my suction side port, as I recently purchased a robotic vacuum that does not connect to the filter.
Is it possible that I have no suction from my main drain, given the labels on the valve before the filter pump? Is this normal?
When I remove the diverter skimmer suction seems to improve considerably.
Does the diverter provide any function in my setup? Seems like it's just limiting suction to skimmer.
I have also read that the diverter will send water to the pump should the skimmer basket become clogged. I don't see how this is possible in my case, as I have only 2 inlets to my filter pump - one for skimmer and one for a suction side vacuum.

Thanks.

 

[Jimrahbe]

Dan,

If your main drain does not have a valve at the equipment pad, then the main drain is plumbed into the hole nearest to the water in your skimmer.. This is why there is no suction.. In "theory" you can adjust the diverter to allow some of the pump's suction to be diverted to suck water from the main drain.

I have two rent house pools that are plumbed this way, and neither have floating diverter valves.. This means the main drains no longer function, but you don't need a main drain in most cases anyway.. In the past I tried to get the floating diverter to work and was never able to get to the point where is was reliable and just give up.. This has been about 10 years ago and the pools don't seem to care...

If this were my pool I would take the diverter out and just move on.

Thanks,

Jim R.

 

[DanF]

Thanks Jim. From your response, it seems like I am getting no "safety" benefit from the diverter; i.e. it's not protecting my pump from lack of skimmer flow. Is this your understanding also?

 

[Jimrahbe]

Dan,

I guess if you never looked at your pool for a month or more that might be an issue with the water getting too low or the skimmer clogging.. But that is something I don't do, so I am not at all worried about it..

So in my case it has never been an issue.

Thanks,

Jim R.

 

[DanF]

Thanks again Jim. I look at my pool lots, so I'm not worried when I'm home. We're gonna be away for a month soon, but I'm having someone come weekly to check baskets and chemicals, so I should be OK.

 

[Richard320]

divertervalve.gif

• Richard320
• Jul 15, 2020

 

[Jimrahbe]

Richard,

I like your diagram... Very easy to understand..

Thanks for posting it,

Jim R.

 

[DanF]

Hi Richard I saw this diagram in searching prior to my post. However, given I don't have an operating main drain (no return to the filter) is this relevant to me?

 

[Richard320]

Hi Richard I saw this diagram in searching prior to my post. However, given I don't have an operating main drain (no return to the filter) is this relevant to me?

The second hole in the bottom of your skimmer goes to the main drain. No diverter means no suction at the floor. The image you posted shows the plate fully closed, which explains why you had lousy skimming -- - it was all from main drain. Or most, anyway. It's fine to leave it out. The main drain doesn't do all that much for circulation, I've discovered. Even set to draw from the drain exclusively, brushing debris to the drains doesn't see it get sucked in and whisked away.

 

[guinness]

Also look at the video below at 1min 42sec to see a diagram

 

[DanF]

Maybe I'm just dense but in my pool configuration, where would water sucked into the main drain go? The only two inlets to my filter pump are from the
skimmer and from a no longer used wall-side suction.

 

[guinness]

Forget the wall-side suction for now and look at the skimmer plumbing below. The float valve sits at the bottom of the skimmer, just above the pipe openings. When the float is pulled down all water from the main drain is diverted to the pump (no water is coming from the skimmer).

 

[DanF]

Ok guiness I think I've got it now. I initially thought the pipe from the drains at the bottom of the pool went directly to the pump. But that would make the diverter useless LOL.

So...with the plate closed (100% suction from main drains) I should be able to dive down and feel suction at the drains? I think I've tried that before and didn't feel any suction. That's why my confusion perhaps.

 

[guinness]

I think that's what Richard alluded to at the end of his post. The main reason for the equalizer is if the water level falls below the skimmer entrance or your basket is clogged with leaves then the float drops and your pump isn't sucking air.

 

[Rocket J Squirrel]

You should not feel suction at the main drain. It's a safety issue. Imagine a small girl's long hair. Modern drain covers prevent palpable suction.

That does not mean there's no flow to the drain. Dive down with some dye or food coloring and see whether it gets sucked in.

 

[Richard320]

You should not feel suction at the main drain. It's a safety issue. Imagine a small girl's long hair. Modern drain covers prevent palpable suction.

That does not mean there's no flow to the drain. Dive down with some dye or food coloring and see whether it gets sucked in.

This.

 

[DanF]

I GOT IT NOW!!!! Thank you everyone! I think I will use the diverter (partially open) when I'll be away from home for a few days just to safeguard against lack of flow to the pump.