How to install skimmer equalizer?

[Wahoo]

Probably a simple question here - I inherited a pool when I bought my house 3 years ago. Old pool. No skimmer equalizer under either skimmer basket, which explains why there's no suction from the main intake at the bottom of the pool. In a previous thread someone told me I needed the Pentair #85015200 assembly which I now have (2 of them).
How do I adjust the "flap" on the bottom to get the right mix of draw from the skimmers and the bottom? Pic below (not of my model, but same concept).

 

[Pool Clown]

First, lets get the terminology correct. What you purchased is a diverter or float valve. The equalizer is, in the case of two or more skimmers, or in a commercial application, a line that runs from the forward, or the hole closest to waters edge in the skimmer, to the pool. Typically, this line will "daylight" through the wall about 2 feet under the skimmer throat.

Purpose:
When the system is running normally, you can adjust the amount of water that is drawn from the forward hole by closing/opening the flapper. Closing the flapper increases the draw from the forward hole. Wide open only reduces the draw, thanks to "path of least resistance".

In the event that the pool water level drops to a level that can no longer supply the skimmer/pump with enough water, your float valve will drop and seal a pathway between the two holes. That will force the pump to draw its water from the forward hole in the skimmer, either the main drain (in the case of a single skimmer), or the equalizer, thus preventing a loss of prime. You can check the operation of this by lifting the weir, preventing water from entering the skimmer, and confirm that the float valve drops and seals. You will know if this happens because the skimmer will fill back up and you will observe no action in the skimmer. You should only hear a brief "slurp" before the float drops. If the slurp goes on for several seconds, your valve is not sealing, and you may loose prime.

Your float valve should have come with a replacement oring that goes in a groove at the bottom of the skimmer. You should use this replacement even if there is one already in place.

IOW, replace it!

 

[atttech-2]

As for "the right mix" most choose to leave the cover wide open this will give you the most flow possible with a diverter installed through the skimmer and the least from the main drain although there will still be some. Skimming is your first line of defense in keeping the pool clear of debris so the more of that you have generally the better. As the skimmer fills with leaves there will be a shift of suction to the MD due to path of least resistance this would happen with or without the diverter in the skimmer.

When you brush the pool you may choose to close the cover diverting more or all assuming no equalizer of the suction to the MD so it can suck up the dirt you brush towards it.

 

[Wahoo]

Thanks for the comprehensive answers and educating me on the correct terminology. Unfortunately, the float valves I bought did not come with O rings (and I don't see any already in the skimmer) so I guess that's my next step. It seems counter-intuitive to me to think the "path of least resistance" would ever be the forward hole, unless the skimmer basket were really filled up (?) Put another way, I started down this path when I observed there was absolutely zero draw from my bottom-of-pool intake and then discovered the role of the float valve. Wouldn't I have to close the flapper at least a little bit to ensure the suction is being diverted to the main drain?

 

[atttech-2]

Because of the twists and turns the water has to take to get below the float valve that is going to create some restriction and cause a bit more suction to the MD and if the opening that the cover can go over is smaller that the diameter of the opening in the bottom of the Skimmer that goes to the MD and pump that is a further restriction.

The other thought I have, and this is just a thought and not tested or proven as far as I know is that the rate of flow will affect things. If you have the pump at a low rpm most of the water is going to come through the skimmer by way of the weir because it is not very resistant the water is just sitting up there gravity is even going to help a bit, it does not have to be pulled up through the pipe like the water connected to the MD does. If however you add a little debris in the skimmer and/or a higher RPM that is when it is going to start pulling more from other normally more resistant sources such as the MD. It could be that the ratios between he 2 is a constant assuming no debris but that would still mean an increased flow from the MD at higher RPM.

I have read many posts questioning if a MD is even needed there are quiet a few that don't think they are and add little benefit. The two things I know they can do from experience is 1.) keep the temperature in the deep even (no stratification where when you dive down you hit ever colder and colder layers), and 2.) keep the water flowing if you get a plastic bag sucked into the skimmer. The third thing they can do is aid in sweeping but as you and many have discovered that is normally not the case. If you close the cover in the float valve I suspect you will get a better result my float valve does not have one so I have no real world experience. For many sweeping dirt to the MD is not a big concern, myself included and I am still working on landscaping and have more dirt than most entering the pool. I find if I brush enough to keep the particles somewhat in suspension the filter eventual does it's job.

 

[mas985]

Don't forget that the MD will divert flow away from the skimmer which can affect how much debris is pulled from the surface. To me skimming is much important than the MD.

As for #1, a return pointed downward can do the same thing.

#2 has never happened to me nor has the skimmer ever fully clogged but if you don't use a float and don't close the MD, you basically have an equalizer that will pull mostly from the skimmer unless the skimmer clogs and then it will pull more from the MD. Best of both worlds.