Pressure gauge always low

[Elwood5487]

Hi TFP,
I'm a brand new pool owner (purchased w/ home) and have been fumbling my way through opening a poorly winterized pool since May 1.
Every aspect of this process is 100% new to me and I have a ton of questions. For this post, I'm hoping to learn what it could mean when a pressure gauge is always running low (just under green). We have a Doughboy Sand filter 2.
Some days the water from the return looks strong, some days weak. The skimmer is emptied 2x daily, pump 1x daily.
I have no idea when the sand was changed or anything else that may be going on internally.
This may or may not matter (again, still learning), but my filter does not have a site view or a rinse feature, so when I backwash it's always a guess as to how long to let it run.
The options on my filter are: Filter, pump to waste, filter to waste, recirculate, backwash, winterize.
Please let me know if I left out any other relevant information.
Thank you.

 

[Texas Splash]

So you have a few "unknowns: that need to be checked one at a time. Here are some thoughts:
- Does the gauge fall to zero when off? If not that's a bad gauge, Yours may still be bad anyways if it was left out all winter. You can get a very nice glycerin-filled gauge HERE.
- Make sure there are no water restrictions from the pool suction port or skimmer back to the pool. If all of your plumbing is above ground, that should be easy to check.
- Also make sure everything on that suction line is air-tight. It may not leak water, but it can let air in. Usually that presents itself by air in the pump basket or bubbles at the return jets.
- If you don't know the history of the filter and sand, it would be good at some point to do a sand deep clean. Sand never goes bad unless the previous owners added pool store gunk like floc or clarifiers. If in doubt, you can always change the sand so that you know it's good.

Hopefully the low pressure thing is nothiing more than the gauge itself. But if you have anymore questions about anything, just let us know.

 

[ajw22]

The color markings on your gauge are meaningless. Every filter system is unique and runs at different pressure. There is no range it must be in.

Note your pressure when your filter is clean. Backwash when the pressure rises by 25%. Learn what are the normal numbers for your setup.

Routine Pump/Filter Maintenance

A working Filter and pump are vital parts for your pool. Read our artiticle on how to clean your filter & other Pool Maintenance Tips.

www.troublefreepool.com

Troubleshooting your Pump/Filter

A broken pump or damaged filter can cause the homeowner headaches. Prolonged damage can lead to a green pool. Click here to fix your equipment issues.

www.troublefreepool.com

 

[Elwood5487]

Coincidence or not?... The pump (Hayward - unknown model) has started losing prime within 20 min or so of me opening the lid and reinstalling. I replaced the O ring and had the same result. There are no leaks, there is no debris inside. Could that be impacting the pressure gauge? When I unplug, take the lid off, put it back on, plug back in it turns on and works. Then a big plume of either sand or yuck is pushed back in the pool.
If it's not the O ring, debris, or leaks, what else could it be?
Very grateful for this forum and all the generous expertise.

 

[Richard320]

Look for a vortex in the skimmer caused by low water or a sticking weir. That can starve a pump which will lead to low pressure and even to lose prime. Shutting it up allows the skimmer to refill. It might reprime just fine without you taking the lid off if you wait the same amount of time.