Problem with daikin 4MXS installation

[thomas86]

Dear,

I'm new in the field of airco/heat pump installations. For my first installation of a 4MXS heat pump i was at the stage of making the system vacuum when suddenly refrigerant was starting to come out of the vacuum pump.

I connected the vacuum pump at the service valve, gas side. I did not touch the gas stop valve.
First all was going well, but after 30 seconds, it seemed suddenly some gas was released. Pressure gauge went to "atmosphere" and a bit of smoke was realeased from the vacuum pump.

What can the problem possibly be? A defective service valve?

Will I have lost too much R411?

[install monkey]

did u pressure test with nitrogen - upto 40bar, could be mositure in the vac pump oil creating mist, keep vaccing, maybe change the oil in the vac pump- service valve wont pass at 1 bar neg pressure

[thomas86]

no, not a pressure test with nitrogen (was not mentioned in the installation manual...)

the vacuum pump was filled with oil and tested 2 months ago and now used for the first time.
can moisture also account for the sudden increase at the pressure gauge?

[install monkey]

nitrogen will prove the system integrity,and absorb moisture, then vac using a torr gauge

[thomas86]

My electronic leak detector also went crazy... and I smelled what i think was r410a

Or could it be the oil mist? Does this also trigger the leak detector?

[thomas86]

Ok, i finished the installation.

One last question, when i vac, it went to for example till 500 micron and then i shut of the pump, it went like an exponential to 2000 micron
i kept on vacing till 180 micron, and then it increased to 1000 micron when stopping the pump but stayed at this level for 4 minutes
is this normal?