Heat pump help

[guest]

Installed a 3 ton 410a American Standard heat pump condenser with a new lineset. I put 100psi pressure test on lineset and detected no leak . then pulled vaccum and still no leak. when i cracked the valves open and and released refrigerant. A weld gave way on the 3/8 line just enough to make a small drip of oil appear. Step by step what should i do ?? Any advice would be greatly appreciated thank you.

[nicolacozma]

Welcome!
100 psi (6,9 bar) is not enough to do the pressurization test, for this reason you have this problem.For R410A the standard testing value is 40bar(580psi). Also you have to let the system under pressurization enough time in order to be sure that there is not any leak.

Now you have to recover all the refrigerant, repair the leak, vacumming the system, charging with the right charge and run it.

[frank]

The recommended pressure for strength testing on R410a is 600psig. Your test at 100psi would not show up any defects in the pipework installation.

I'm assuming that you used oxygen free nitrogen for testing?

Vacuum testing is only for detecting the presence of moisture, not for leak testing.

Have you been doing this very long??

[frostedflake]

600 psi???

is that safe?
i've read on some condenser plates that the maximum pressure must be arround 450 psi, what happens if one over pressurizes the system?

[nike123]

600 psi???

is that safe?
i've read on some condenser plates that the maximum pressure must be arround 450 psi, what happens if one over pressurizes the system?

In hot days near or above 100°F you could easy have 500 psi of normal working pressure of R410A in condenser.

[Thermatech]

Heating mode example

In Europe split systems which are refrigerant R410a & have a high pressure safety switch are often set at 41.5 bar cutout.

Think about what will happen if the enduser forgot to clean the indoor unit filter & the system is running in heating mode
then
the system will run up to over 40 bar with poor air flow through the indoor unit coil.

Provided you have carried out the interconnect refrigeration pipe strength test at over 40 bar then you have proved that the pipe & joint connections are strong enough for that possible running condition.