Pressure Problem

New here - hoping for some help.

Have a 20K gallon in ground pool just opened. Pressure last year at sand filter was about 12 to 15 PSI. It is now only 3, barely able to vacuum. Tried a drain king to clean out skimmer line to no avail. A little air in pump basket area, not much. Pump impeller looks clean.

Here is the kicker - I seem to get more flow at the skimmer when in waste mode than in filter. Don't get a pressure reading unfortunately when in waste or recirc mode. Any ideas would be much appreciated.

Have you backwashed your sand filter?

membership upgraded.

Yes, backwashed several times. When running in filter mode, the pressure is only 2 to 3 PSI. If the filter was clogged I would expect the pressure to be higher.

you put drain king in your skimmer . acid probably not goodfor it . if good pressure in waste mode still works ,so look for the blockage inline . does it dump alot of water during backwash good flo?

Had a pool company here yesterday. They blew out all lines with a blower, inspected multi valve, still no idea. Get good flow on backwash or waste, very low in filter or recirc mode.

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Originally Posted by ballen

Get good flow on backwash or waste, very low in filter or recirc mode.

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=> restriction in the pool return lines, possibly at the eyeballs.

We blew out the return lines with a blower yesterday. If there was blockage in the returns, wouldn't I be experiencing high pressure at the filter instead of 2 PSI? Not sure how effective the blowout was, it was just a blower not high pressure CO2 or a compressor. Thanks for keeping up with this - the local pool guy is stumped as well.

It's not practical to check for restrictions to hydraulic (liquid) flow using a gas. If want to test the lines, use a separate pool pump, flow meter and gauge.

But, have you checked the eyeballs in the returns??

Problem solved. The new pump I installed came without the diffuser. I took the one off my old pump, and away she goes. Thanks for all the help and I am sure I will be back for more.

Thanks for coming back to tell us what the problem was. So many times, there are threads where people are scratching their heads trying to figure out what the problem is and then we never hear the conclusion to the story. When people do come back and report the resolution to their problem, it helps others in the future who may be reading this thread. So...... thanks!

Quote:

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Originally Posted by ballen

The new pump I installed came without the diffuser.

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What do you mean? In the image below, #6 is the diffuser:
https://lh5.googleusercontent.com/-j.../Super2-ed.jpg

But self-priming centrifugal pool pumps cannot function properly without this part. I haven't tested it, but I'm pretty sure this pump (and most pool pumps) wouldn't pump at all, without the diffuser.