Again low pressure

[bocman93]

Something weird with my pump, one day is work good and another day low pressure and air, basket fills just to the half
1) Water level high
2) Skimmer flipper doesn't stuck
3) Just replaced o ring and pump seals
4) No leaks around pump and filter

Also when I close skimmer or drain valve it cause low pressure too (clogged both lines?) So all my lines is always fully open
I research forum and can't find nothing more
Please give me some more recommendations, because I already getting crazy

 

[reggiehammond]

Clean filter? A plugged filter can cause all sorts of issues you describe.

 

[bocman93]

Clean filter? A plugged filter can cause all sorts of issues you describe.

You mean sand filter? If yes, It was replaced in 2019 but I never clean it, just backwash

 

[reggiehammond]

You mean sand filter? If yes, It was replaced in 2019 but I never clean it, just backwash

Might want to pop the top and check condition? There's a great article about deep-cleaning a sand filter in pool school. A lot of non-TFP advised clarifiers / floculants, etc can really gum up the filter to the point of restriction.

 

[bocman93]

My mystery solved!
In one pipe on suction side valve wasn't installed properly so I can't closed it all way
I replaced the valve, closed this pipe and everything work
Now my question is, any ideas where this pipe can go and why sometimes it have air in? (I attached the picture)