Pump sucking skimmer dry

pawn

New member
Aug 29, 2018
3
Burlington/Ontario
Hi all. Sorry to jump in here and immediately ask probably a common question but I spent a couple of hours searching around as there's a lot of conflicting information out there so here goes:

I have a fairly small pool installed just this spring. I estimate it's somewhere between 7,500 and at most 10,000 gallons.
It's a 24x12' pool made up of three intersecting circles (kind of kidney shaped). There is one skimmer and two outlet jets. The pump is a single speed 1 HP (Hayward Superpump). I suspect it's too powerful.

Basically since day one it's been a struggle to get the pump primed upon start-up or after vacuuming. It bothered me but it would always eventually start circulating normally after letting it try for a while. Now I can't get it to stay primed. It continually rises to almost 20 psi, sucks the skimmer dry then loses prime, shuts down and tries again over and over. Right now I have it running off the vacuum to keep the circulation going and it works perfectly (except of course no skimmer).

The questions:

- Does it sound like I'm right that the pump is oversized? I've read numerous online posts and articles that suggest there could be other problems like air leaks, low sand in filter, blockage but then I doubt it would work well with the vacuum hooked up.

- Is there a quick fix to restrict the flow while I sort this out? The plumbing is all glued together so swapping out the pump or adding a valve right now will be a total pita (the hillbillies that installed our pool did not provide any control or diverter valves). I was looking online for possibly outlet jets with a ball valve but I couldn't find anything. We have a short pool season where I live that's almost over so I don't want to shut down for even a couple of days if I can help it.

If I add a valve, should it go before or after the pump? I can only find conflicting information on this online including arguments about which is right. Or maybe it's a stupid idea entirely and I would just put in a smaller or variable speed pump?

Thanks in advance!
 

sktn77a

Gold Supporter
May 16, 2010
1,153
Chapel Hill, NC
Could be the pump is moving too much water. Not much you can do about it if that's the case (except get a smaller pump). However, I'd check the weir is floating freely (as above) and also that your water level is at least half way up the skimmer throat.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
13,086
Bedford, TX
Pawn,

I don't believe it is possible for your pump to suck the skimmer dry unless you Weir door is stuck up or the water level is way too low. It just can't happen..

Go out and make sure the water level is about in the middle of the skimmer opening. Then manually hold the weir door down and turn the pump on and tell us if the water in the skimmer runs dry or not.

I can understand how the pump can start sucking air, but that is not the same thing as the skimmer running out of water...

Thanks for posting,

Jim R.
 

pawn

New member
Aug 29, 2018
3
Burlington/Ontario
Oh my, thanks all. I can confirm there is no weir door at all. I thought this was odd but not surprising considering how unprofessional the pool installers were. But I never would have thought its absence would cause this.

Looks like I came to the right place! Thanks again, I'll follow up with how this turns out.
 

JohnT

Admin
Mod Squad
TFP Expert
Apr 4, 2007
9,538
SW Indiana
Oh my, thanks all. I can confirm there is no weir door at all. I thought this was odd but not surprising considering how unprofessional the pool installers were. But I never would have thought its absence would cause this.

Looks like I came to the right place! Thanks again, I'll follow up with how this turns out.
A missing weir isn't going to cause this problem. You have something wrong with the water level or something clogging the skimmer opening. Pool water will pour into an open skimmer faster than the pump can empty it unless something is stopping it or the water is too low in the pool.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
13,086
Bedford, TX
Pawn,

If this is a brand new pool, it would be very odd indeed if it did not have a weir door... They come built into the skimmer box.. They are often missing on very old pools, where they have broken off over time, but that does not normally happen for many years.

Show us a couple of pics of you skimmer... One from the pool side looking in and the other looking down into the skimmer.

Thanks,

Jim R.
 

pawn

New member
Aug 29, 2018
3
Burlington/Ontario
Well, turns out I was wrong and I do have a wier plate, it's just really recessed and I couldn't see it. So I played with it a bit and everything's working so I guess it was sticking.

Thanks everyone for pointing me in the right direction, when you don't know where to start it's very frustrating. :)