Leaking header

[mallo]

Hi one and all

I have installed a 60 (2 x 30 tube) tube system heating approx 400Ltr HW cylinder.
I pressure the system and it seemed to hold the pressure over night, then filled the system prior to adding the tubes, several months on I seem to be seeing a drip coming out the lower end of the header, I am not convinced it is leaking as it held the pressure during the air pressure test, and the system pressure doesn’t seem to be dropping. I wonder if it could be condensation. The system pressure has never been above the 2.5 to 3Bar running pressure (never dumped any liquid dumped into the overflow tank). And the temperature of the panels has never been above 95 to 100°C there is a heat dump that brings the panel temperature down to approx (a little dependant on ambient temperature) 40 to 50°C.
My main question is could the header be leaking? Have people come across this before? How is the best way to find the leak, decommission the panel (remove the glass), drain the system down, re-connect the pipe work to the other panel, refill the system, and bleed? Remove the header from its casing, look for signs of the leak, pressure test with air or water depending on if the leak can be spotted?
I assume they are only silver soldered?? I have access to this……
Sorry for all the questions.
Best wishes to all,
Michael

[Naptown]

Who' s the panel maker and how old is the system.

[Naptown]

The best way to test for a leak is as follows
Do this just after sunset. Preferably when outdoor temps are not falling rapidly.
Drain the system
Remove the expansion tank and plug the opening in the pipe
Flush and fill the system so there is no air and pressurize to about 30 psi
Watch the pressure gauge if you have a leak the pressure will drop quickly
If you have a leak find and repair.
The reason for removing the expansion tank is the air pressure will take a very long time for the system to lose pressure where with it removed a few drops of water will show up on the gauge.
You do this at night so the collector is not heating up the water causing the pressure to go up or worst case cause damage to the system.
Don't forget to reinstall the expansion tank when finished.

[mallo]

Hi Naptown
Thanks for the post, the system is a SunnPro system, it was supplied about a year ago and commissioned during this summer, there is a 10 year warrantee but the supplier no longer exists as they have gone to the wall…….
As the leak is such a small amount I am not sure you will see it doing a hydraulic pressure test, but that certainly would be the easiest way to go.
The system is on a flat roof, so is fairly easy to get to, and hence why I am thinking it might be better to try and tackle this by removing the header from the system and pressure testing it on the bench??
I am currently waiting my time to see if the pressure drops over time and this may give me a clue to if its leaking?? Its just that its quite a bit of work to take it down to find nothing wrong with it. I wondered if other people have had similar experiences???
If the pressure was dropping at a reasonable rate I could understand, but it just seems strange that it doesn’t seem to be dropping, perhaps in the long term it will show something.
Best wishes,
Michael