Feature
As a rule , your system / pump must be able to reach 500 microns on vacuum , and keep that level , until it is time to commission , this also gives you a clear and immediate indication of any possible leaks on the system . Leaks usually occur where there is a ‘ connection ’, being either welded or flare , and if your system does not keep the vacuum , there is a leak somewhere .
As with all tools , ensuring that the right tool is used for the right application is critical . The size of the pump , usually indicated in CFM , or m ³/ h flow rates , should match the system that you are intending to vacuum ( not using a 2.5cfm ), and then trying to vacuum a VRV rooftop unit used on a building as has been seen , and thus , overloading the unit and causing the electrical motor of the pump to burn out .
“ A tool that has become a requirement by law in most countries , especially of you are doing refrigeration / AC work is the refrigerant recovery unit .”
Generally , all wear-and-tear parts of vacuum pumps can be replaced , thereby turning this tool into a lifetime investment .
REFRIGERANT RECOVERY A tool that has become a requirement by law in most countries , especially of you are doing refrigeration / AC work is the refrigerant recovery unit . This unit is similar to the vacuum pump and being able to perform most of the same functions of the vacuum pump , it is still different .
It not only vacuums the refrigerant , but it also condenses the refrigerant , and pumps it into a recovery cylinder .
The recovery units are used to evacuate and recover the refrigerant into a service cylinder , and not venting the refrigerant into the atmosphere , as this has a direct impact on greenhouse gasses and global warming , and is illegal , in most environmentally conscious countries .
These are refrigerant cylinders that usually have connections for both liquid and vapour , and can be used repeatedly , after the recovered refrigerant has been properly disposed of or recycled . These are not disposo cans , which are meant for one time use only . Disposo cans should never be used to recover refrigerant !
Ensuring your vacuum pump oil level is always sufficient and |
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replacing the oil when it starts to show any signs of cloudiness |
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or particles in the oil , is crucial to the life span of the pump , and |
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should ensure many years of reliable service from your vacuum |
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pump , just look after your tools , it is as simple as that . |
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Evacuating a refrigeration or air conditioning ( AC ) system is |
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also of utmost importance to safeguard a long lifespan of the |
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compressor ( s ). Millions of compressors are destroyed every year |
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due to an inadequate evacuation process , leaving residues of |
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moisture in the system , which leads to irreparable damages and |
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consequently a costly replacement of compressors . |
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A proper evacuation process avoids this , but requires a lot |
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of time , and time is money as they say – however , there are |
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ways to evacuate more efficiently , by simply increasing the |
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flow rate . Removing the Schrader valve increases the diameter |
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tremendously , thus allowing the refrigerant during recovery and |
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evacuation to flow faster . |
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The removal or even exchange of Schrader valves at systems |
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under pressure can easily be achieved with valve core tools that |
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are available for various pipe sizes . A further improvement of |
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the evacuation speed can be achieved with a hose of a larger |
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diameter ; this allows a quicker evacuation and filling process , |
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and new pumps today have been especially designed for deep |
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vacuum applications . |
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Deep vacuum requires a strong vacuum pump ( here , torque |
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and tightness by high accuracy are more important than |
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horsepower ), which enables he HVAC / R technician to pull a |
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constant vacuum down to 15 micron . |
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www . hvacronline . co . za |
RACA Journal
I April 2021
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21 |