We got our pool mid-season last year. 16x34 vinyl with Pentair equipment (FLT FNS PLS36 DE Filter, Superflo SF-N1-1A pump, Intellichlor Salt Generator, and Mastertemp 250 Heater). Last season we had good suction in the skimmer, noticeable suction that held the basket down. The return jets (2 of them) had good strong pressure. The PB took the filter guts to the shop to clean them during the off season. When the PB opened the pool this spring (we’re in Western PA) things seemed fine, but the skimmer didn’t seem as strong nor did the returns. We had a lot of pollen so they came and cleaned the filter. Things still seemed weak, but the PB didn’t seem concerned. This morning, without making any changes or doing any maintenance, the jets were easily 5x as strong and just visually looking as the skimmer you could see it moving much more water. My filter pressure also dropped from about 25 (where it started the season and stayed constant) to around 16. What would cause such a dramatic change in pump performance? Something large stuck in a line? We have a skimmer and floor drain and two returns.
Sudden return pressure and skimmer suction
- Thread starter Bigfish322
- Start date
Hi, welcome to TFP! Maybe there was a partial blockage in the line. You can always check the pump strainer pot and see if anything got sucked in there. How was the pool closed for winter?
The PB closed it. The pump, filter housing, and SWG were all removed and stored inside and caps were put on the plumping connections. I believe the only thing not capped was the heater. I think it just had duct tape over the inlet/outlet. We did have issues with the heater in the spring where the heater continued to cycle on/off. The PB said there was a bad thermostat not opening, so he replaced it and it worked great.
The pump strainer has a couple things in it, but nothing major. Not that it’s a big deal, but I noticed that the viewing glass now has no air bubble in it. For the last few weeks there was always an air bubble. Is that indicative of reduced or less than normal flow?
So, as zea3 says, some type of obstruction is no longer there and has given you greatly increased flow. The guage on your filter is likely at quite a different reading than it was before.
All in all, what happened was a good thing. Check your pressure gauge daily so you can definitively document further changes, if any
Tell us what "viewing glass" you are referring to
First, thank you for the welcome and for the responses. The viewing glass I mentioned is just the top of the pump where you can see the strainer basket. There was consistently a bubble there, now there is not.
It does sound like something was partially blocking the line and interfering with water flow. What you see now is good. You don't want to see an air bubble in the top of the pump strainer basket. Do you get a lot of organic debris in your pool area? Leaves, spent blossoms, blowing dirt or yard clippings? If so it is possible that the pool guy vacuumed up some debris that got stuck and partially clogged the line when he was closing. If you get a lot of organic debris and you manually vacuum the pool its a good idea to get a leaf catcher to add to the vacuum hose. It will collect the leaves before they get to your pipes.
It is possible you had air in the system causing your pump not to work very efficiently.
Is there water still in the pump basket (that's the one with the glass) after the pump is off for an extended period of time or does it stay full of water?
Is there water still in the pump basket (that's the one with the glass) after the pump is off for an extended period of time or does it stay full of water?
I’ll have to test the pump being full of water after extended off. I typically run the pump 24/7 during the season. That may or may not be correct for a single speed pump and SWG, but that is what my PB suggested. Would air stay stuck in the line for a month? Like someone mentioned, whatever happened seems to be a good thing because things are running correctly now. The question that will hang over my head is, is there a ghost in the machine that is going to pop up again? Again, thanks for all of the questions ideas and general feedback!
A little off the subject, but running a single speed pump 24/7 is overkill and expensive. You could probably have a clean pool with 1/3 that many hour and save quite q bit of money.
Your system is neat and clean kudos to both you and the PB.
Your system is neat and clean kudos to both you and the PB.
If I bumped down my pump run time from 24/7 to say 8/7, does that mean I’d have to increase the output % of the SWG from 25% to 75% so that it maintains the chlorine level?
Essentially, yes, but I would try 50% to see if the SWG can keep up before I went to 75%.
Under normal conditions, no heavy usage or piles of kids in the pool for hours, would you run the pump for 8 hours at one time… say from 10a - 6p, or would you run the pump twice daily for 4 hours each broken up over 24 hours…. say from 10a - 2p and then from 12a - 4a? Maybe it doesn’t have to be that complicated??
There is no right or wrong answer and "trial and error" is the best solution.
The goal here is twofold, Run long enough to....
1. keep your pool really clean
2, Generate enough chlorine to match up with the FC/CYA chart.
I like to be around when the pump is running if possible so I would likely set mine from 6-9 AM, then maybe 3-6 pm and finish at 7-9pm.
You have to judge the results and adjust accordingly
The goal here is twofold, Run long enough to....
1. keep your pool really clean
2, Generate enough chlorine to match up with the FC/CYA chart.
I like to be around when the pump is running if possible so I would likely set mine from 6-9 AM, then maybe 3-6 pm and finish at 7-9pm.
You have to judge the results and adjust accordingly