Original message
| rocketrod71
 |  "Vacuum Pump - Flushing Agents"
, posted Thu 5 Jul 18:18  
Can anyone help with flushing agents and vacuum pumps.
We have flushed out a system with flushing agent following a compressor burnout.
We are now having trouble achieving a vacuum on the system and feel that it has something to do with the flushing agent.
We have raised the temperature of the system above the boiling point of the flushing agent, however it is taking absolutely forever to achieve a suitable vacuum. We are struggling to get it below 1,000 microns.
Has anyone got any ideas?
Dallas Air - Sydney Australia
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Replies:
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| rocketrod71
| "Re(1):Vacuum Pump - Flushing Agents" , posted Mon 9 Jul 04:09
Success at last.
We have achieved a vacuum of 500 microns and stablising at 800microns.
Obviously we are now going to do multiple drier changes.
Any suggestions on oil changes?
We have a hermetic compressor, with no oil charging ports.
How do we get the oil out and how can we change it effectivly?
Dallas Air - Sydney Australia
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| | chiller guy
| "Re(2):Vacuum Pump - Flushing Agents" , posted Mon 9 Jul 07:42
Congratulations!
Since you have no access to the oil sump the only option may be changing "acid core" driers as necessary. This will be dictated by your acid test results if you can capture any oil. Otherwise, you may have to just make a couple of changes based on your knowledge of the systems contamination and hope for the best.
You could also start tracking the motor insulation value (megging) and watch for changes. This all gets pretty involved and expensive and the system is not that big. So you do a balancing act between cost and reasonable action.
Above all, try to determine why the last compressor failed. Most of the time (not always)it is something external to the compressor.
All refrigerants are safe - All refrigerant are dangerous. The difference is YOU !!!
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| chiller guy
| "Re(1):Vacuum Pump - Flushing Agents" , posted Thu 5 Jul 18:45:
Think of your system as a "wet" system now and treat accordingly. The flushing agent has gotten into every low spot in the system and pooled there. You now have to boil off these pools with the vacuum. There are two ways to handle it. Use the biggest vacuum pumps you have and change oil frquently until dry or drill holes in all the low spots (tubes), drain any liquid, solder the holes and then go back to step one. All the while keeping the temps as high as pratical.This is assuming that you have tried blowing out the circuits with nitrogen.
It is much easier to clean up a burnout using the refrigerant and refrigeration oil within the system but then hindsight is great.
All refrigerants are safe - All refrigerant are dangerous. The difference is YOU !!!
[this message was edited by chiller guy on Thu 5 Jul 18:49] |
| | rocketrod71
| "Re(2):Vacuum Pump - Flushing Agents" , posted Thu 5 Jul 20:35
Why would you use flushing agents at all?
Is this always the situation with flushing agents?
Dallas Air - Sydney Australia
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| | chiller guy
| "Re(3):Vacuum Pump - Flushing Agents" , posted Fri 6 Jul 08:31
That was going to be my question to you but I did not want to appear a Smart A--. In the past (I'm old) we only used R-11 as a flushing agent and feminine napkines as filters. However; we stopped that process 30 yrs ago when science and experience proved a burn out can be cleaned up by running the new compressor and changing oil and driers as necessary. There is no easy or cheap way to do this process but whenever you add anything but refrigerant and refrigerant oil to a system you will have side affects.
Just out of curosity, what did you use as a flushing agent?
Good Luck
All refrigerants are safe - All refrigerant are dangerous. The difference is YOU !!!
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| | rocketrod71
| "Re(4):Vacuum Pump - Flushing Agents" , posted Sun 8 Jul 05:06
http://www.erg1000.com/ufaprodinf.pdf
The above was the flushing agent we used.
45kW system cooling capacity
300lit capacity of vacuum pump and still struggling to pull under 1000 microns after 1 week of vacuum.
I have set up driers for easy changing so will have to start the compressor early this week and operate, but with regular drier changes.
Anymore tips on the frequency of drier changes?
Dallas Air - Sydney Australia
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| | chiller guy
| "Re(5):Vacuum Pump - Flushing Agents" , posted Sun 8 Jul 08:04
They advertise that stuff as a "cure all". If you have been pulling down for a week you may have a leak somewhere. Was the compressor, TXV, and other components removed from the system while you were pumping the solvent?
After charging the system run for about 4-8 hrs before changing the liquid line driers (acid cores of course)and watch the pressure drop on the suction drier (3 psi Delta max). Also get some "one time "acid test kits and check the oil. You may have to do a change here too.
As I said, this is not cheap or easy, but if not done properly you will be back doing it again in the near future.
For refrence what type of system are you working on? Recip,DX or flooded evap,chiller or air to air evap,package system or field built, and what refrigerant and oil?
All refrigerants are safe - All refrigerant are dangerous. The difference is YOU !!!
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| | rocketrod71
| "Re(6):Vacuum Pump - Flushing Agents" , posted Sun 8 Jul 16:18
Thanks for your reply.
We are working on a 45kW R22 water cooled package unit.
Everything was removed from the system and we pulled one vacuum on the system before the compressor was put back into the system.
We are sure there is no leaks because we have been thourough with the vaccuum.
We isolated the system in two parts to try and isolate where the agent was. The two lowest points are one in the liquid line and the compressor. I was able to blow a bit more of the flushing agent out of the liquid line, however the compressor is a large hermetic Hitachi compressor which I can not access!!
We will now look at starting up and performing regular drier changes.
Dallas Air - Sydney Australia
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