Refrigerant recovery is one of a service technician's most typical jobs when maintaining or repairing HVAC systems.
That's why you should invest in a good refrigerant recovery unit in Australia. Understanding the various recovery strategies will aid you in completing this crucial duty as quickly as feasible. Furthermore, following proper refrigerant recovery techniques can protect both you and the equipment while ensuring that you did the operation the first time efficiently.
Safety is one of the most crucial aspects of refrigerant recovery. You'll need the right equipment for the refrigerant you're trying to recover. R-410A systems, for example, run at much higher pressures than R-22 systems. It implies you'll require equipment designed to manage R-410A's greater pressures.
To avoid frostbite, you'll first need a pair of safety goggles and a sturdy pair of gloves.
Adding to the blue and red low- and high-side ports, most technicians employ a manifold set with two centre utility ports — 14-in for recovery and 3/8-in for vacuum. Check to see if the manifold gauges are suitable for the refrigerant pressure you'll be using.
It also requires a set of charging hoses with ball valve ends. Both the hoses and the assemblies must be UL approved. Also, make sure your hoses are in good working order before using them. It's great to utilize the shortest hoses possible for a given project since this will allow for more effective recovery and less environmental damage.
More Safety Information
You'll need a good recovery unit as well. Desirable features are a big condenser, a compressor protection regulator (CPR) valve, and a high-pressure cutout switch rated at least 510 psi. Some manufacturers include a subcooling capability, a great method to speed up recovery times in hot environments.
Last but not least, you'll require a suitable recovery tank. When recovering R-410A, you'll need a DOT 400 recovery tank from the US Department of Transportation. The high pressures of R-410A are too much for a typical DOT 350 tank to operate properly. As a result, ensure that you have the correct tank for the job and don't overfill it (a DOT regulation). Another DOT law is that the tank is recertified every five years, so double-check the date on your tank.
Different Recovery Methods
There are three fundamental methods for recovering refrigerants: liquid, vapour, and push-pull.
Liquid recovery is the quickest of the three recovery strategies. Using the liquid recovery method, you can transfer refrigerant while it's still in a liquid condition. This approach is particularly useful for moving refrigerants from one container to another. So, why not make use of it? Because not all HVAC systems are capable of doing so. You'll have to apply the vapour recovery procedure in those circumstances.
Vapour recovery is more consuming than liquid recovery, but it is also the most prevalent. It merely transports refrigerant in vapour form. The liquid recovery and vapour recovery processes are extremely similar. The status of the refrigerant and various parameters on the refrigerant recovery unit are the only changes.
Push-pull recovery removes liquid refrigerant quickly, but it's a two-step process: After you've taken all of the liquid in the first step, you'll need to switch hose attachments to recover the vapour. You should employ the push-pull approach when you have more than 10 pounds of refrigerant in a system.
Refrigerant Recovery Unit: Liquid Recovery
The liquid recovery method involves transferring refrigerant while it is still liquid. Let's go over the steps one by one.
- Ensure that the system you're fixing is turned off before you begin. Check that the selector knob on the recovery machine is turned off. Also, check that all valves on your manifold are closed.
- Connect the high side of the manifold to the liquid port and the low side to the vapour port of the system being serviced.
- Connect a 14-in. utility pipe from your manifold to the recovery machine's suction port.
- Lastly, attach a hose from the recovery cylinder's liquid side to the discharge port. Ensure the hose ends with the shut-offs are used at the suction and discharge ports. It is a legal requirement.
- Remove any non-condensables from all hoses before starting the recovery.
- You can now turn on the recovery unit by opening the liquid valve on the recovery tank.
- Set the recovery unit's selector valve to "liquid."
- On the manifold, open the high-side valve and the utility port.
- The unit will continue to recover until the low-pressure switch is turned off and the bulb reads "recovery complete."
- You can now turn off the system switch. Also, turn off the selection valve as well.
After each service, you must purge the recovery system. Purging removes the refrigerant from the recovery unit, lowering the risk of cross-contamination and extending the life of your equipment. Turn on the system and choose "purge" on the selection valve.
Refrigerant Recovery Unit: Vapour Recovery
The refrigerant is recovered from an HVAC system in a vapour condition during vapour recovery. The recovery unit then condenses the vapour into a liquid then sends it to the recovery cylinder. To a point, the basic procedure is similar to liquid recovery.
Ensure the system you're servicing is turned off when you're ready to begin. Check that the selector knob on the recovery machine is likewise turned off and that all valves on the manifold are closed.
- Connect the high side of the manifold to the liquid port and the low side to the vapour port of the system you're working on.
- Connect your manifold's 14-inch utility hose to the recovery machine's suction port.
- Finally, connect a hose from the recovery cylinder's liquid side to the discharge port.
- Ensure the hose ends with the shut-offs are used at the suction and discharge ports. It's a legal requirement.
- Purge all hoses of non-condensable before recovering refrigerant into the recovery cylinder.
- Switch on the recovery unit and set the selector valve to "vapour."
- On the manifold, open the utility port and the low-side valve.
- The device will continue to recover until the low-pressure switch is turned off and the bulb reads "recovery complete."
- Turn the system switch off and the selector valve clockwise to off once the recovery is complete.
- After each recovery, you must purge, so turn on the system switch and select "purge" on the selection valve.
Your vapour recovery process is complete when the equipment shuts down again, and the bulb reads "recovery complete."
Refrigerant Recovery Unit: Push/Pull Recovery
Technicians use the push-pull recovery method when moving huge amounts of the liquid refrigerant. The recovery unit "pulls" vapour from the recovery tank and creates high-pressure discharge gas, which "pushes" liquid back into the recovery cylinder from the HVAC system.
You should not use the push-pull approach if:
- There are less than 10 pounds of refrigerant in the system.
- The system uses a heat pump or equivalent machine with a reversing valve.
- If the refrigerant system does not allow for the production of a solid column of liquid, the system has an accumulator between the service ports employed in liquid recovery.
When executing a push-pull recovery, you'll require additional equipment due to the altered setup: An extra hose, a sight glass, and a recovery cylinder with no more than five pounds of refrigerant. The sight glass should be rated for the refrigerant pressure you're using are all things you'll need.
You're ready to begin once you've gathered everything you'll need.
- Attach a hose from the recovery unit's discharge port to the HVAC system's vapour side. After that, run a pipe from the liquid side of the HVAC system to the sight glass and then to the recovery tank's liquid side. Lastly, link a hose from the recovery tank's vapour side to the recovery unit's suction port.
- Before beginning recovery, cleanse the hoses of non-condensable once all connections have been made.
- Open the recovery tank's valves.
- Set your recovery unit's selection valve to "vapour" and turn it on. The process of recovery will begin.
- Keep a close eye on the sight glass while you're recovering. The first step of the recovery is completed when the passing liquid no longer appears through the sight glass or when the scale reading finishes rising.
- Shut the vapour valve on the recovery tank and operate the recovery unit until the lamp on the recovery unit displays "recovery complete." Turn the system switch "off" and the selector valve clockwise to "off" once the recovery is complete.
- To prevent the refrigerant loss, you must purge the lines at this stage. Turn on the system and choose "purge" on the selection valve. The purge is complete when the machine shuts down again, and the bulb reads "recovery complete."
- Close the "liquid" valve on your recovery tank and turn it off.
- You can now rejoin your hoses as though you were performing a conventional vapour recovery.
- As previously said, push-pull is extremely fast when properly set up, but it is not always the best option because it is a two-step procedure.
- Turn the selector valve to "vapour" and conduct the vapour recovery process until the machine shuts off once the hoses are reconfigured for this type of recovery.
- Before you start servicing your HVAC system, purge it once again.
This last purge removes any remaining refrigerant from the recovery unit, lowering the danger of cross-contamination and extending the life of your equipment. Always remember to cleanse after each service!
HVAC Shop Refrigerant Recovery Unit
There are different methods of refrigerant recovery available. But one thing's for sure. Any technique won't work with a quality refrigerant recovery unit. That's why HVAC Shop gathered great brands to offer to you in Australia. Our one-stop HVAC shop also offers other products like refrigerant scales, vacuum gauges, and so much more!
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