Do I have a leak?

[Israel clayman]

I need help I was at 40 PSI overnight I dropped to about 32 now it was 70° yesterday got down in the 40s last night does anybody know does that make a difference to where that would be the reason for my drop or do I have a leak?

Originally I pumped it at 60 PSI held it for an hour had no drop went to 30 PSI for about 2 hours no drop then put it at 40 and went to bed woke up to this just hoping that somebody can tell me the weather plays in effect....

 

[Texas Splash]

So basically it looks like you lost about 8 psi overnight after a 40 degree drop in temp. Let's see if @JamesW has some thoughts. He's pretty good at crunching those numbers and scenarios.

 

[JamesW]

Pressure generally drops by 1 to 2 psi for every 10 degrees the temperature lowers.

30 degrees lower will create about 3 to 6 psi drop.

 

[Israel clayman]

So what you're saying is I have great news and I have no leaks because Dang I don't want to have to try to find that leak lol

 

[JamesW]

8 psi is a little bit more than expected.

I would watch it some more to be extra sure.

Maybe get some soap solution and spray it on any suspected areas that might possibly leak.

 

[Bill1974]

If you want to put your mind as ease, get out the spray bottle of soapy water and start spraying the joints and looking for bubbles. If there are any leaks, I would suspect it at your threaded fittings or your test plug.

Temperature swings and the sun hitting the pipes and ground will make the pressures change. As a general rule for car tires, there is about a 1 psi different for each 9°F temperature change.

The pressure change is larger than I would expect for the temperature change, but I am going to guess you used an air compressor and it did not have a drier or water trap on it. So what might explain the larger pressure drop is the water vapor in the compressed air condensed out and caused the pressure to drop in addition to what pressure change was for just the air.

 

[Israel clayman]

If you want to put your mind as ease, get out the spray bottle of soapy water and start spraying the joints and looking for bubbles. If there are any leaks, I would suspect it at your threaded fittings or your test plug.

Temperature swings and the sun hitting the pipes and ground will make the pressures change. As a general rule for car tires, there is about a 1 psi different for each 9°F temperature change.

The pressure change is larger than I would expect for the temperature change, but I am going to guess you used an air compressor and it did not have a drier or water trap on it. So what might explain the larger pressure drop is the water vapor in the compressed air condensed out and caused the pressure to drop in addition to what pressure change was for just the air.

So the soapy water thing when I was testing my pressure stick I built I kept losing pressure over a 24-hour period but nothing over a two or three hour. Sprayed 10 gallons of Dawn dish soap and water could not find a leak finally went and bought a big old tub stuck it down in there and there was a teeny tiny little leak every few seconds from one of the fittings but at this point I believe it was just the temperature drop

 

[Bperry]

there was a teeny tiny little leak every few seconds from one of the fittings but at this point I believe it was just the temperature drop

You should fix that leaking fitting before covering things up.

 

[Bill1974]

I just went through the same thing. I have replaced all my pool line and had a new liner put in earlier this year. trying to get skimmers, returns and my test plug to seal were a challenge. The returns ports were the biggest challenge. But I did find that one if not both return fitting were cracked and leaking.

One thing to be careful of is putting to much pressure in, I don't know if the skimmers and return fitting that go through pool wall are meant to take much pressure. My pool never gets above 25 psi and that's between the pump and filter.

On a fun note, pool plumbing makes a great air cannon. I launched a test plug about 40 to 50 feet up and into the neighbors yard and lost in a holly bush. What surprised me was the pipe only have 25 psi in it. It also made me be a little more careful when pressurizing the lines to not stand in the line of fire. I was only using friction fit plugs.

 

[Israel clayman]

I just went through the same thing. I have replaced all my pool line and had a new liner put in earlier this year. trying to get skimmers, returns and my test plug to seal were a challenge. The returns ports were the biggest challenge. But I did find that one if not both return fitting were cracked and leaking.

One thing to be careful of is putting to much pressure in, I don't know if the skimmers and return fitting that go through pool wall are meant to take much pressure. My pool never gets above 25 psi and that's between the pump and filter.

On a fun note, pool plumbing makes a great air cannon. I launched a test plug about 40 to 50 feet up and into the neighbors yard and lost in a holly bush. What surprised me was the pipe only have 25 psi in it. It also made me be a little more careful when pressurizing the lines to not stand in the line of fire. I was only using friction fit plugs.

What did you use to plug your skimmers? I've been trying like heck to get those sealed to pressure test I've tried Teflon tape three or four times and put liquid Teflon on there and I cannot get it to seal?

 

[Bill1974]

I had to try a few things too before it got it to seal. What I ended up using was a CPVC sch 80 pipe nipple with a cap glued on the end (I bought on 2 ft piece and cut it in half, since i have two skimmers). I cut a few threads off the end so it would make a tighter fit before bottoming out. Also used a fair bit of thick teflon tape. I did not want to use pipe dope, but that was my next try if this did not work. One thing with pipe dope it helps if you let it set up for a day before putting pressure on it.

For the return lines, I tested them before attaching them to the fitting that goes though the pool wall and seals with the liner. I had to have those fitting replaced, one or both were cracked. I tried testing again after they were replaced and they leaked where the eyeball threads in at anything more than a few psi with everything i tried to seal it with. The face plate does not have much threads and really no sealing area. They are Hayward 1408 fittings. If the 4 screw were on a larger bolt circle they would be a flat surface between the 4 counter sinks and the threads to seal on. For these I did the soap bubble test to look for leaks and also could fill the pool up and look for bubble coming from spots it should not come from with winterizing plugs in.