Boiler pressure test loosing pressure

rickster05

Plumbed yesterday.  Filled to 50psi for test.  Lost pressure over 6hrs.  Soaped all joints, no bubbles-leaks.  Tested boiler block prior, held 15 psi indefinitely.  

Want to fill it and see, would make the fix more difficult though…

GroundUp

Was there a drastic temperature change, by any chance? What is the relief valve rated for and why is it over 30 psi?

WMno57

Maybe you know this, but ...
Your gauge has two scales. It shows 20 PSI which corresponds to the pressure needed to heat a radiator 50 feet above the boiler. So, at the moment you took the photo, your system had 20 PSI.
Water molecules are larger than air molecules. That's how Goretex works. So your air leak might not leak water. Also, sometimes small leaks plug on their own. This worked better with steel pipe than it does with copper pipe, but sediment and corrosion can plug a small leak at low pressures.

rickster05

GroundUp said:

Was there a drastic temperature change, by any chance? What is the relief valve rated for and why is it over 30 psi?

Relief valve rated for 30psi.  Guess I was reading the gauge wrong.  Another member said i actually charged the system to 20psi…

rickster05

WMno57 said:

Maybe you know this, but ... Your gauge has two scales. It shows 20 PSI which corresponds to the pressure needed to heat a radiator 50 feet above the boiler. So, at the moment you took the photo, your system had 20 PSI. Water molecules are larger than air molecules. That's how Goretex works. So your air leak might not leak water. Also, sometimes small leaks plug on their own. This worked better with steel pipe than it does with copper pipe, but sediment and corrosion can plug a small leak at low pressures.

I didn’t know how to read it…. Your remarks remind me of my grandfather though!  Hanky Panky always said with threaded connections, don’t worry they will seal over time if they’re small which obviously this is.  Really appreciate the advice!

WMno57

Suggest you bump the pressure up to 29 PSI and re-do the soap bubble testing.

rickster05

WMno57 said:

Suggest you bump the pressure up to 29 PSI and re-do the soap bubble testing.

Will do!  Thanks!

GroundUp

Never raise the pressure in a system to within 5# of the relief rating under any circumstances. 25 psi maximum with a 30# relief

rickster05

WMno57 said:

Maybe you know this, but ... Your gauge has two scales. It shows 20 PSI which corresponds to the pressure needed to heat a radiator 50 feet above the boiler. So, at the moment you took the photo, your system had 20 PSI. Water molecules are larger than air molecules. That's how Goretex works. So your air leak might not leak water. Also, sometimes small leaks plug on their own. This worked better with steel pipe than it does with copper pipe, but sediment and corrosion can plug a small leak at low pressures.

WMno57 said:

Suggest you bump the pressure up to 29 PSI and re-do the soap bubble testing.

Will do!  Thanks!  So bumped it up to 30 PSI.  This was before/after for 15 minutes.  Less than ~3 PSI loss.  No bubbles after applying more soap…

WMno57

Looking good! Maybe drop it to 20 and let it sit for a day.

rickster05

After filling the boiler I found the small leaks…I forgot to check the packing nut on the ball valves.  Simple fix.