Pressure Question

[TDockUSC]

Hey guys, quick question about filter pressure. My system is about 6 months old and the pressure typically sits at 18. I backwash when it gets over 20 and it always drops back to 18. It's been that way the whole time I've had the pool.

Today I added 3 lbs of CYA via the sock method. I put it over a return and it let it sit for about an hour, squeezing every 15 mins. That was today at about 4:00pm.

I just went outside to change the timer so that my pump will run for the next 24 hrs (because of adding the CYA) and noticed that my filter pressure is down to 14. It's never been that low before.

The only variables are that I added the CYA today and that my pool temp is higher than it's been because it's warming up. Would either of those things cause my pressure to drop? If not, any ideas what's up? Should I be concerned?

Thanks!

 

[Thom53us]

Are you sure that your inlets haven't changed like those ball directional covers. They restrict flow and it sounds like you have less restriction somewhere. Is there sand in the pool?

 

[TDockUSC]

I’m not 100% sure what you mean. Where would these covers be?

I inspected my set up again this morning and nothing looks different to me. And there’s no sand in the pool.

 

[duraleigh]

Sounds like a restriction on the suction side. Somewhere between the skimmer and the pump there might be a partial blockage.

 

[TDockUSC]

Thanks, duraleigh. Based on your feedback, I checked for obstructions and cleaned out the basket at my pump. That raised the pressure from 14 to 16. While there, I noticed something I else that I had never seen before (but had never really looked at before.) I've attached pics to help clarify.

There is a small, circular thing right before my basket at the pump. It looks like it has a hinged washer of some kind in it. When I looked at it just now, it appears to be filling the area and looked like it maybe came loose.

Like I said, I've never noticed it before so maybe this is how it's supposed to look or maybe it's come loose. (Please forgive me, I am completely out of my depth with this stuff!)

Does this look right?

 

[duraleigh]

That's a check valve. It prevents water from going backwards back to the pool. It is very helpful but it, too, can catch debris and that would cause a drop in your psi.

As you can see, it can be disassembled and cleaned rather easily should you ever notice it clogged.

 

[TDockUSC]

Thank you for that explanation. Very helpful.

I guess my question at this point is do I wait it out for a few days or is there another step to take?

Cleaning the basket raised the pressure up to 16, and I normally sit at 18. Is that amount worth worrying about?

 

[mknauss]

Filter pressure through a sand filter can change some as any channels in the sand are rearranged or sand is distributed differently during a backwash.

How far above your pool level is your pool equipment? Typically there is no need for a check valve in that position. It creates additional resistance to flow so if not needed, the guts in it can be removed.

 

[TDockUSC]

How far above your pool level is your pool equipment?

The equipment is next to the pool and the same height as the pool deck. So it’s probably 6-8 inches above the waterline.

 

[mknauss]

Personally, I would remove the guts from that check valve. It is not necessary.

 

[mknauss]

Personally, I would remove the guts from that check valve. It is not necessary.

Only caveat - your spillover spa. Does it have a return line where it is running all the time? They may be using that check valve, which is not properly placed, to prevent draining of the spa when the system is shut down.

 

[TDockUSC]

Only caveat - your spillover spa. Does it have a return line where it is running all the time?

Yes, my water drains from the skimmer in the pool and returns to both the pool and spa when in "pool" setting. In "spa" setting, it drains from the spa and only returns to the spa.

 

[mknauss]

Do you have automation? If so, you could set up a Spillover function such that your spa spillover would only be used a couple times a day to keep the spa chlorinated. That would reduce your aeration and your overall pH rise.

 

[duraleigh]

A check valve can be helpful if there is a tiny leak in the suction side (pretty common). That leak can drain the filter and make priming difficult. The check valve will prevent that in many instances.