Filter PSI dropping during the day

[tomintampa]

For 5 days straight my DE3620 filter pressure will run at 13-13.5 psi (which has been my normal) until very late in the afternoon.
Today it read 13.5 at 3:15, checked again at 6 and it was just a tad under 10 psi.

The pump strainer has a periodic short burst of very small bubbles at the very top of the glass lid every few seconds (not continuous bubbles)
Bubbles are very hard to even see unless I get nose to nose with the pump lid.

Assume I have a small air leak. But wondering why it would only drop psi late in the day after running steady and normal all day.

I checked the return eyeballs for tightness, checked cleaned and relubed the pump stainer lid gasket.

Vac Pool cleaner and returns are running at normal strength.

Is this something I should worry about if the late day psi drop doesn't get worse than the current 3-4 psi drop.

Thanks

 

[cowboycasey]

can you shut the pump off in the afternoon after the PSI drops, wait a couple minutes and turn it back on? what does the PSI go to then? From the sounds of it your pump is getting tired... I have no idea what that means or what could be happening to slow the pump down....

It may be the bearings but I am not sure, there may be other things going on...

If it were the filter doing its job the PSI would go up not down...

hmmmm, maybe someone else will have an idea

 

[Newdude]

Assume I have a small air leak. But wondering why it would only drop psi late in the day after running steady and normal all day

Do you have a VS pump ? Possibly with automation ? Either could have reset its schedule due to a power failure/surge.

Fill out your signature with as much info as you know because it helps folks not have to ask you questions about your questions, like the one I just asked. if you have a single speed pump it changes the answers to your question.

Either way, @JamesW is the pump whisperer. He’ll have great thoughts.

 

[duraleigh]

A loss in psi indicates a restriction on the suction side. That it occurs in the afternoon says your flow through the suction side is being reduced in the afternoon.

Is your water clear? Do you run your pump only during the day? Is the skimmer getting partially clogged with debris?

 

[tomintampa]

Thanks to everyone who replied, sorry for wasting your time. I am learning all the time, sometimes the hard way.

Turns out the drop was due to my pool's solar heating panel shutting down due to lack of sun late in the afternoons.

When the panel is activated psi hits that 13.5 spot and when off reverts to the 9.5 -10 psi range.

Never realized an operating solar panel raises psi.

I'm constantly learning.

Thanks again