If by some unforeseen circumstances you come across an air conditioner or roof top unit with a “burnt out compressor”, all is not lost! All it means is you have some work to do in cleaning up the entire system.
Burn outs cause acid in the system and we have to make sure it is removed before we replace the compressor. There are a few different things that we will need to make sure this acid is handled:
The first task once you’ve got all of the new parts and accessories is to recover all of the existing refrigerant. Once you have all of the refrigerant removed, it’s time to remove the old compressor and filter drier. Now with the suction and discharge lines removed at the old compressor and the liquid line open from removing the drier (if a suction drier has been put on the unit, it must also be removed), you will want to start flushing with the RX-11 through the discharge line through the condenser and out of the open liquid line.
Follow the direction with the kit, then push dry nitrogen through as well. Once you are confident that is cleaned out, move on to flush the evaporator through the suction line. Always push with dry nitrogen through the entire system -- sometimes flushing back in the opposite direction helps clear and clean the lines.
Once you are sure the system is clear and clean, you can start welding it back together. Remember, always bleed nitrogen through the system while you are brazing. Both suction and liquid driers should be installed and the acid scavenger should be poured into the compressor through the suction port.
Once the system is all brazed back together, it’s time to start the evacuation process. The first evacuation stage is 1000 microns -- pull down to that and wait about 30 minutes to check for leaks. If the system will not get to 1000 microns, you either have a leak or moisture in your system. Once the system will hold 1000 microns for 30 minutes, break the vacuum with dry nitrogen and then evacuate down to 750 microns and let that stand for 30 minutes. Then, break that vacuum with dry nitrogen and then evacuate down to 500 microns or less. Once that holds, break the vacuum with clean refrigerant and recharge as needed. Now that you have taken all of the proper precautions, your system should operate as usual.