Mysterious pressure increase when changing between returns and waterfalls

Jump to latest Follow Reply
B

BCinAustin

0
Oct 15, 2014
30
Austin,TX
I recently noticed that when I switch the flow of water from 100% to the in pool returns, to 100% to the waterfalls, the pressure reading on my Hayward DE4820 filter jumps from about 18PSI to almost 28PSI. Attaching a video. Any idea what might cause this? Do you hear that noise before I switch the valve? I think it comes from the mutliport valve. Sounds like sand bouncing around in there, but I'm guessing it's actually air?

Also, in case it's related, I've noticed lately that when I turn the pump off, there's a surge of pressure that forces water to squeeze out from the lid of pump strainer. The gasket on the lid is a Hayward part, is well lubed, and was recently replaced.

http://youtu.be/R7QdJDgoL8w
 
The pressure change is normal. Each different plumbing run has it's own unique pressure, which depends on pipe size, pipe length, number of fittings etc.

Everything else you describe sounds like you are getting air drawn into the system somewhere. Take a look at this article in Pool School for details on where to look for air getting in.
 
Thanks JasonLion! If I'm seeing the water splash out from the pump basket lid, does that mean that's the source of my air leak? Or could air still be coming in somewhere else and then forcing the lid up when the pump is shutoff?

I'll check all the other typical spots in the morning when I can see better.
 
BCinAustin said:
Thanks JasonLion! If I'm seeing the water splash out from the pump basket lid, does that mean that's the source of my air leak? Or could air still be coming in somewhere else and then forcing the lid up when the pump is shutoff?

I'll check all the other typical spots in the morning when I can see better.
Click to expand...
The pump basket lid should be sealed, so that is what I would be looking at....
 
I agree that it's air being drawn in on the suction side. The noise is probably due to the air causing cavitation in the system. The reason the sound is reduced at higher pressure is that the water is going slower and the higher pressure reduces cavitation. I think that there is cavitation on the pressure side where fast moving water creates low pressure around sharp angles.

If water squirts out when the pump is turned off, that's a likely spot for an air leak.
 
JamesW said:
If water squirts out when the pump is turned off, that's a likely spot for an air leak.
Click to expand...

Thanks everyone. I recently replaced the o-ring on the lid with an original Hayward part. I do notice the lid seems to twist on alot easier than it did with the old o-ring (which was pretty well worn and had lots of "texture" from years of suspected unlubricated use by the previous owners). I took the o-ring out this morning and wiped it down (in case I'd somehow over lubed it) and then put it back into the lid lightly (hoping to let the suction of the system seat it properly).

That seems to have diminshed the amount of water that is pushed out when I turn off the pump, but it definitely didn't stop it altogether. I definitely never recall this happening with the older o-ring. It seems like it started happening around a month ago, after I'd already replaced the o-ring, but when I noticed that our filter pressure had risen to a point that a backwash was needed. I figured that maybe after backwashing, the decrease in overall pressure might help, but it doesn't seem to have done anything. I checked both the plugs on the pump this morning. I re-lubed their o-rings and reinstalled. There does not appear to be any leakage around them (air in or water out). If my ears are telling the truth, I hear a faint air leak (sucking in) in the vicinity of the lid once the pump is off. I also then see/hear a bunch of air bubbling into a see-through port on a pipe that runs out from my multiport valve to the pipes that feed my returns/waterfalls. I have manually released all the air out of the DE filter.

Not surprisingly, I have also noticed that the pump is not holding prime. After it's been off for a while, the water level in the basket vessel has dropped at least by half.

Could it be that the lid itself is now defective? Should I posted a video of the pump lid leaking water and bubbling port near multi-valve when I shutoff the pump?

Could it be the gasket inside of my multiport?
 
I don't believe it's ever run dry. Usually it keeps some water and when I've watched it recently it does manage to achieve prime relatively quickly and stay full while on. I really don't see hardly any air through the pump lid while it's running, after it's full (but I guess if it's a small leak, it could be well blended and later cavitating as someone was speculating).

I'm starting to wonder if I've just got the wrong o-ring. I sent my info to Hayward (Hayward Northstar pump (SP4015NS), serial #: 630D33) and they said I needed SPX4000TS. That's exactly what I bought http://www.amazon.com/gp/product/B004VTGEV0/ref=oh_aui_search_detailpage?ie=UTF8&psc=1. But it's pretty notable how much easier this one twists on.

With the old one, I couldn't imagine there being enough play in the lid for it to raise up and let any water out.

I'll try the soap trick and see if I can detect any sucking.
 
Update from Hayward. They've confirmed that I've got the right ring, but admitted that my Northstar has a lot of power and can sometimes create enough pressure to budge the lid on start and shutoff. As a courtesy, they're going to send me a different ring that might create a tighter fit at the lid. I'll keep everyone posted. Thanks as always for the help.
 
BCinAustin said:
Update from Hayward. They've confirmed that I've got the right ring, but admitted that my Northstar has a lot of power and can sometimes create enough pressure to budge the lid on start and shutoff. As a courtesy, they're going to send me a different ring that might create a tighter fit at the lid. I'll keep everyone posted. Thanks as always for the help.
Click to expand...
wow, that's customer service!
 

Enjoying this content?

Support TFP with a donation.

Give Support
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply