I had a call out late yesterday afternoon found 1 circuit completely flat tube rubbed at condenser tube sheet and dropped complete charge and it was raining all day. Welded it up put 2 new drier cores in her and nitrogen purged it then started vacuum pumps
Energized load/unload and master oil solenoid to pull a vacuum. I used 2 pumps both large 7 or 9 cfm refcos I used one at the compressor on high and low side with micron gauge on low side, and installed the other on the liquid line above the drier shell started and pulled a 14 hour vacuum on it.
It pulled down to 500 microns so shut the pumps down and isolated the system and left to come back later and see how it was holding. Came back at 1 this evening and it had come up to 1175 microns after sitting for 5 hours.
Decided I was going to bring it up to 5-10 psi using dry nitrogen and let it sit overnight so the nitrogen could grab some more moisture out of it then start another vacuum monday morning.
Here's where it gets interesting I have a theory of what happened but want some of your opinions and what I need to do to safely start it back up. I haven't had this happen before. I did forget to de energize the load/unload and master oil solenoid if that's what caused this.
I set my nitrogen regulator on 30 psi and began introducing slowly into the discharge line side of the compressor only. I was watching my gauge above the drier shell and was trying to get it to about 15 lbs to leave it overnight. It was almost out of the vacuum and into positive pressure above the drier shell when I began hearing a gurgling sound inside the condenser above the compressor the gurgling then continued to get louder and I began to hear it sound almost like water running inside the condenser down into the compressor and then into the suction line heading to the chiller barrel. At that point I remembered I forgot to de-energize the load unload and master oil solenoids and then killed them and turned off the nitrogen. Then just listened and watched and waited and the noise got less and less and my pressures slowly equalized at 15 psi at the discharge line on the compressor and above the drier shell at the service port after about 5 minutes. When I disconnected my gauges at the suction line on the compressor I had a steady stream of oil come out of my service hoses.
It's my theory that somehow due to pressure being applied on the discharge and a vacuum still existing on the condenser it sucked the oil cooler dry once a siphon action started. What would need to be done to safely start this circuit back up if it did actually suck the oil cooler out into the system. Any of you have other ideas as to what could have happened.
Sorry to be so long winded but I wanted to give a blow by blow so others could offer ideas and suggestions. Flame suit on if I made a idiot mistake.