New Construction Pressure Test

[jsteve17]

Good morning! I am doing an owner/builder pool build and ended up having to do my plumbing due to not being able to find a plumber.

Yesterday morning I pressured the system up to ~31.5 lbs (72 degrees air temperature). It rose to about 33.5 lbs by mid-day (88 degrees). This morning (24 hours later) it is down to just a smidge below 30 lbs (72 degrees). So, I've lost about 1.5-2 lbs in 24 hours. Due to the repairs, I know there is a bit of air in the lines, which explains the rise in pressure mid-day. However, now we are down to the same temperature when it was initially charged, and it is ~2 lbs lower.

I have a standpipe in one of my 2 skimmers with the hose spigot and pressure gauge. In the other skimmer, I have a plug that was hand tightened (as I cannot get a wrench on it). In the one with the plug, I see about a tablespoon of water in there this morning. I also have 3 main drains, with plugs, but they have water in them due to watering the gunite. So, not sure if they are leaking a little bit.

I've walked around the plumbing and do not see any water around any of the fittings. Though, I'm not sure how much of a drip it would take to drop 2 psi in 24 hours.

I know this is probably a stupid question, but is that normal? I'm sure the answer is no, it shouldn't change at all over 24 hours, but thought I'd ask. Could it be due to some stretching of the pipes, and/or due to air in the system?

Maybe at this point, I just need to let it go another 24 hours and see if it drops any more?

I appreciate any input.

 

[Bill1974]

I went through this too. With the volume of plumbing there will and temp changes it will cause pressure changes. The pressure changes will be even greater went these is a mix of water and air in the pipe. The best I can recommend is to check at the same time of the day when the weather conditions are same. If you are seeing pressures rise and not only drop I would take that as a good sign. A slow drip leak in a line would probably be evident over a few days, but it depends on how much of the line in air vs water.

On a side note, it's pretty entertaining when a test plug doesn't hold and gets launched. With some water in the lines it start to look like old faithful when it lets go too. I never found that plug either.

 

[jsteve17]

I went through this too. With the volume of plumbing there will and temp changes it will cause pressure changes. The pressure changes will be even greater went these is a mix of water and air in the pipe. The best I can recommend is to check at the same time of the day when the weather conditions are same. If you are seeing pressures rise and not only drop I would take that as a good sign. A slow drip leak in a line would probably be evident over a few days, but it depends on how much of the line in air vs water.

On a side note, it's pretty entertaining when a test plug doesn't hold and gets launched. With some water in the lines it start to look like old faithful when it lets go too. I never found that plug either.

Bill1974, thank you for your reply. I've taken it up to 50psi on some recommendations to help find a leak (if there is one) sooner.

I had the same thing happen. The cap on the floor return for the spa hadn't gotten glued in place. Just press-fit. So, when I first pressured up the system to 50psi, it shot off as you described. The cap landed back in the spa and I glued it back on.

 

[JasonAnt]

Did something similar when we sold our house 13 years ago. The buyer wanted a new bath tub spout installed since the old one leaked. I installed it the morning of closing. I stopped the old house a week later to pick up something we left behind and the new owner told me his teenage son took a shower that first night and when he pulled the diverter valve, the tub spout shot off and hit him in the shin. Whoops! Forgot to tighten the little allen screw.