Why an In line check valve?

[SaintRonin]

Moved from this old 2014 thread... In line check valve?

Yes, it could, but would partly depend on your plumbing setup, if you have a skimmer only or main drain plumbed through the skimmer as a vacuum break then it would stop loosing water when the skimmer ran dry, instead of the height / depth of the return fittings or ground level which ever is higher.

Just came across this when looking at the check valve info and now I finally understand why they would have plumbed my skimmer and drain together. Thanks!

 

[Jimrahbe]

Ron,

I believe that most older pools have the Main Drain plumbed into the bottom of the Skimmer... Most new pools have both the Main Drain and the Skimmer plumbed back to the equipment pad..

When the main drain is plumbed into the bottom of the skimmer there should be a floating diverter valve that turns the main drain on whenever the water level drops below the mouth of the skimmer. In theory this prevents the pump from running dry. In actual practice the diverter is missing in most cases, and even when the diverter is still there, it only seems to work about 50% of the time.

In most cases, the main drain is just not needed... there are thousands of pools out there with either no main drain, or non-operating main drains, and they all work just fine.

Thanks for posting,

Jim R.