Pressure Gauge

[Reebs]

My pool has been opened for about 3 weeks this season. The filter was extremely clean at start-up and for the past several weeks the pressure gauge has remained at the initial level from when the pool was opened (the pool has not been used much and the pool has stayed clean with just a few vacuum's). However, yesterday and today, the needle has dipped below the starting point. I have never seen the needle go lower when the filter is running normally- of course it usually rises over time. Is the dip in pressure anything to be concerned about (picture attached)? The filter is functioning normally and the water test results are normal.

Thanks!

 

[jblizzle]

For the pressure to drop, you would need to have a restriction between the pool and the pump or the pump and the filter. Are your skimmer and pump baskets clean? Maybe something is clogging the impeller?

 

[Richard320]

First, shut off the pump. Does the gauge drop to zero? If it's above or below zero with the pump off, you just need a new gauge.

If that's not it, look for any valves you might have forgotten to move, and look for a restricted skimmer or strainer. Simple rule of thumb: restrict the output, pressure goes up, restrict the imput, pressure goes down.

 

[Reebs]

Thanks to both responses. The two pool skimmers are very clean. The filter skimmer was about 30% blocked with debris. I shut everything down, cleaned that filter and the pressure went to "normal" (right in line with the green arrow). Was that slight blockage enough to cause the dip? I assume so. That filter basket has been blocked before to that degree, but I don't recall the needle ever going lower than the baseline.

On a separate note, you asked if when I shut my pump off does it go to zero- The gauge drops to about 5 or so. I cant say if that is what it has always done, but if I had to guess, I think its always dropped to around there for what my memory will give me.

 

[Richard320]

If it doesn't drop to zero, I wouldn't trust the pressure readings. It's not just simple arithmetic to say if it reads 5 instead of zero, subtract 5 from whatever. It could be that you really only dipped 1 psi. Or it could be 10. Pick up a new gauge the next time you're somewhere that sells them. They're standard pipe threads, so it doesn't have to come from the pool store, although a generic gauge won't have those nifty pointers to show clean pressure.

 

[Reebs]

Thanks to both responses. The two pool skimmers are very clean. The filter skimmer was about 30% blocked with debris. I shut everything down, cleaned that filter and the pressure went to "normal" (right in line with the green arrow). Was that slight blockage enough to cause the dip? I assume so. That filter basket has been blocked before to that degree, but I don't recall the needle ever going lower than the baseline.

On a separate note, you asked if when I shut my pump off does it go to zero- The gauge drops to about 5 or so. I cant say if that is what it has always done, but if I had to guess, I think its always dropped to around there for what my memory will give me.

- - - Updated - - -

Thanks for the help

 

[jblizzle]

Time to get a new gauge. The glycerin filled ones are much nicer. I recommend the ones that Dave sells: http://tftestkits.net/Flow-Meters-and-psi-Gauges-c12/

 

[Reebs]

That price is certainly reasonable. Forgive the novice questions...Is it truly as easy as unscrewing the existing and screwing a new one on? I trust I have a rear mount (if you look at my photo)? Lastly, my pool company has always "set the Green and Red arrows", once the pressure gauge got about halfway, I always back-washed at that point. With these, how do you know when to do so?

 

[Richard320]

That price is certainly reasonable. Forgive the novice questions...Is it truly as easy as unscrewing the existing and screwing a new one on? I trust I have a rear mount (if you look at my photo)? Lastly, my pool company has always "set the Green and Red arrows", once the pressure gauge got about halfway, I always back-washed at that point. With these, how do you know when to do so?

After you backwash or teardiwn and clean your filter, you'll get your clean pressure. When it goes up 25% or you notice a decrease in flow from the return, you backwash again. Say it's 12, for easy math. 25% is 3 psi. So when it goes to 15, it's time again.