If you work in the HVACR industry, you should know that if you're servicing or disposing of a piece of equipment that contains refrigerant, by law the refrigerant must be reclaimed and placed into an acceptable storage container. In 1990, the Clean Air Act of 1990 mandated that all chlorofluorocarbons (CFC) and halocarbons, containing fluorine, chlorine, carbon, and hydrogen (HCFCs) be reclaimed. Prior to July 1, 1992, the only accepted practice for removing refrigerant from a system was to release it directly to the atmosphere. There was no other widely used method for disposing it.
Luckily for all of us, reclaim machines have not only become smaller since they were first introduced, but they have also become a lot faster. The first unit I ever used weighed over 75 pounds and reclaimed four pounds per hour. It could take half a day to get the refrigerant out of even a small system before you could even start the repair.
The early machines were nothing more than a small refrigeration unit; complete with compressor and a couple extra solenoids and valves. The new oil-less units are capable of pumping small amounts of liquid, and have been a welcomed sight to technicians.
Refrigerant recovery is nothing more than removing refrigerant from a system in which it's installed, and placing it into a drum or cylinder for storage or disposal. The actual process, however, is a little more detailed.
Once it's been determined that a system must be reclaimed, a standard set of refrigeration gauges will be placed on the liquid and suction line ports of the system.
If an empty reclaim bottle is available it should be pulled into a vacuum and connected to the remaining center port hose of the gauge set and left loose.
The high side valve on the manifold should be opened slightly to bleed air and non-condensables through the high side hose as well as the service hose, and out of the loose hose connection on the reclaim bottle (each hose can be purged individually as well, if preferred).
After several seconds, tighten the hose connection on the bottle, and completely open the high side valve on the gauge manifold. You should now have a solid column of liquid refrigerant up to the recovery bottle. If you're able to run the system that's being serviced, it'll speed the recovery process. At this point, it'll be condensing the refrigerant and raising system pressure.
Now, open the valve on the bottle and liquid refrigerant will flow from the high-pressure system to the low-pressure bottle. This will take place until the pressures equalize. If the system is running, it's important to watch the low side gauge to make sure the system doesn't start to run in a vacuum.
Once the suction gauge reaches about one pound, it will be time to shut the system down. With all of the liquid out of the system, it will now be time to connect the reclaim machine.
The hose from the bottle will now be connected to the discharge line of the machine.
Another hose should be connected from the center port of the gauges to the inlet port of the reclaim machine.
A small filter drier should be placed in-line to capture any particles. Lines to the reclaim machine should be purged, and high and low side valves on the manifold can now be opened.
The inlet and discharge valve on the reclaim machine should be opened, and the recovery can begin. At this point, refrigerant is now being removed from both the high and low sides of the system. This process will take place until either the LP switch on the machine opens or an adequate vacuum is reached.
Once the machine is stopped with the valves closed, keep an eye on the gauges to make sure they don't rise. If they do, there's still refrigerant present in the system. Another tell tale sign that there's refrigerant still present in the system is frost at low points of the system, as well as in the accumulator.
If none of these signs are present, all that's left to do is purge the lines and the machine. The system is now ready for service or disposal.
Page 2 of 2
It's our duty as industry professionals to always do the right thing not only for our customers, but for Mother Earth as well. Reclaim every time.
Ed. note: see sidebar for additional recovery methods.
Allan Smith is President of Air Conditioning Specialists, Portsmouth, VA, and a Trane Comfort Specialist Dealer. He can be reached at 757/558-9122.
Other Recovery Methods
Always use a filter-dryer or particulate filter on your refrigerant recovery unit. It's also important to us an acid core dryer when recovering from a burned out system. Acid and particulate matter will cause damage to your refrigerant recovery system. If you use the appropriate filter on every job, your refrigerant recovery equipment should give you many years of trouble-free service.
The three different recovery methods are: vapor recovery, which is the most common; the push-pull method; and the liquid recovery method, which is gaining in popularity.
The following information describes the steps related to the vapor and push-pull recovery methods. Remember, your system configuration may vary. Check your operation manual to find the proper configuration for your unit.
Vapor Recovery Method
There are 10 steps for proper use of the vapor recovery method:
- Connect a hose with a low-loss fitting on both ends to the discharge side of the recovery equipment.
- Connect the other end of this hose to the tank liquid port on the recovery cylinder.
- Place the recovery cylinder on a scale.
- Connect a hose from the low-side service port of the HVAC system.
- Connect the other end of this hose to the center (charging) port of your manifold set.
- Connect a hose to the low-side of your manifold set.
- Connect the other end of this hose to the suction side of the recovery equipment.
- Connect a hose from the tank vapor port to the high gauge on the manifold set. This will allow you to monitor the tank pressure.
- Close valves on manifold set.
- Open vapor and liquid valves on the recovery cylinder.
- Start the recovery system.
- Allow unit to pull into the appropriate vacuum based on refrigerant type.
- Close all valves and disconnect from the HVAC system, or begin purge cycle.
Push-pull Recovery method
Use the push-pull method only after you have first checked the configuration of the system being serviced. Here are the questions to ask first:
- Are less than 10 pounds of refrigerant in the system?
- Is the system a heat pump, or one with a reversing valve?
- Will the system allow a solid column of liquid to form?
- Does the system have an accumulator?
If the answer to any of these questions is yes, refer to the vapor or liquid recovery methods.
Otherwise, here are 10 steps to using the push-pull recovery method:
- Connect a hose from the tank vapor port to the center port of the manifold set.
- Connect a hose from the low side of the manifold set to the suction side of the refrigerant recovery unit.
- Connect a low-loss hose from the discharge side of the recovery unit to the low-side service port.
- Connect the low-loss hose from the high-side service port to the tank liquid valve.
- Place the tank on a scale.
- Open valves on recovery cylinder.
- Start refrigerant recovery machine.
- Open the low-side valve on the manifold set.
- Monitor the scale.
- Switch the unit over to vapor recovery once the scale stops picking up weight.
Ralph A. Vergara is technical sales manager for Ritchie Engineering; [email protected].