Water Line Leak or Just a Pressure Fluctuation?

[pettrix]

I have a well and it's a new home with PEX in a slab on grade. All tested OK and I wanted to do a test of my own. So I turned off the well pump and the cold water to the water heater. After about 9-10 hours. I turned on the well pump and the pressure stayed where I left it (60psi) and then the cold main line was turned on and pressure was at 60psi. I then turned on the cold line to the hot water heater and the pressure dropped 2psi.

I did turn off the hot water tank for those 9-10 hours so the tank was off.

Is this 2 psi something to be worried about? I don't see any leaks inside the home but could it be a hot water line leak under the slab or is it normal to have a 2psi drop in the hot water line as it cools?

I also have a hot water re-circulation pump which I leave off.

 

[Mr_David]

2 psi drop after 9 hr shutdown is nothing to worry about. could be just the temp of the water dropping.

 

[pettrix]

How much can pressure fluctuate due to the hot water tank cooling off?

I just want to be sure it's not a leak on the hot water line in the walls or slab. I can't see any interior leaks but if it's a slow leak, I might never be able to find it.

There's definetly a drop in water pressure on the hot side of the system. Whether it is just the water heater or a leak, it's hard to tell.

Frustrating...