Plumbing efficiency

[scarob63]

Here is view of current inlets. From left to right: Main 2", Skimmer 1.5", Vacuum 1.5".
I'm in the process of putting in new motor and am wondering about the current plumbing setup. Currently I get cavitation if I shut off main to use just skimmer or vacuum lines.



[attachment=0:1fvxzlix]2012-05-31_13-25-31_440.jpg[/attachment:1fvxzlix]

 

[mas985]

Cavitation or air bubbles in the pump basket? They are not the same thing. Cavitation bubbles can only exist in the impeller inlet and not the pump basket. If you are seeing air in the pump basket, that is likely due to an air leak caused by the high suction head. Do you need to shut off the main line completely to get the vacuum to work?

 

[scarob63]

Air is in basket when main closed. I usually need to turn off main to vacuum. There is no air in basket as long as main is open. I dont see any obvious leaks. Is the smaller jandy valve a concern.

 

[jblizzle]

That sounds like an air leak in the skimmer or vacuum line.

 

[mas985]

You can also have leaks in the pump basket, drain plugs or any valves. Use pool lube on the pump lid gasket and see if that helps. Note too that it is difficult to "see" and air leak. Air can leak in but water may not leak out.

 

[scarob63]

How do I find out where the leak is. I get the same action in the basket with either of the skimmer or vacuum lines.

 

[jblizzle]

If you run a water hose over each joint, you may be able to find the leak if the air in the pump basket goes away.

First check all your pump fittings (lid, and drains). The pump is pulling harder when through the smaller pipe, so that could be enough to pull air in by the pump only when the pump is "working harder".

Since it happens for both the skimmer and vac, that could point to the smaller valve leaking as well.

 

[scarob63]

Thanks, I'll work on it and let you know.

 

[scarob63]

Clarification:

It's not so much that I'm getting air in basket as it's the water level immediately dropping in the basket.

 

[jblizzle]

Well air still had to get in there for the water level to drop right?

Do you get good flow through just the skimmer? Do you get good flow through just the vac? Does the water in the pump look the same when you switch from Main to Skimmer and from Main to Vac?

 

[scarob63]

The water does look the same when switching to main to skimmer and main to vac. New motor will be on tomorrow, but I do get good flow through just the skimmer. I did notice drain on basket was not that tight. I will put some new teflon tape on and fix that. Thanks for the help!