1. 2009 CARE Evacuation & Dehydration Seminar
Presented by:

2. Use Safety Equipment

3. Remove Jewelry

4. Lift and Move Correctly

5. Electric Shock BE CAREFUL! High voltage is always dangerous.
Even 40 volts can be lethal if skin is wet or damaged.

6. Codes
Follow all Local Codes. In the absence of local codes, consult the current edition of the National Fuel Gas Code. 6

7. One Program I Use Most Of The Time Is Snagit.
Training Resource
What Do You Use To Capture Your Photo’s, Diagrams, Written Documents, Etc?
One Program I Use Most Of The Time Is Snagit. 7

8. Monthly Online Training Class
Training Resource
Monthly Online Training Class
HVACChannel.tv 8

9. Mingledorff’s FTP Site
Training Resource
Mingledorff’s FTP Site
Mingledorff’s FTP 9

10. Hose Safety Inspection
Yellow Jacket recommends that you inspect your hoses on a regular basis.
If they are over five years old they recommend you replace them. (Common practice, replace once a year)
After some time hoses can be come porous

11. Terminology
Micron — One thousandth (1/1,000) of a millimeter or of an inch. A micron is a unit of measurement used in measuring a vacuum.
Vacuum — The absence of matter in a space. In HVACR terminology, it refers to the absence of air and water vapor within the refrigerant system.
Noncondensables — Gases that will not condense in the condenser.

12. Terminology
Dehydrate — To remove water and water vapor from the system.
Evacuation — The removal of water vapor and air from the system.
Deep vacuum — Refers to pulling a system down to as low as 20 microns. This method is accomplished by way of a two-stage vacuum pump.

13. Terminology
Triple evacuation — A method of evacuation that initially pulls the vacuum down to between 1,000 and 2,000 microns. Then a small amount of refrigerant or an inert gas such as nitrogen is introduced into the system. The object is for the gas to absorb moisture from the system. The gas is then purged, and this process is repeated two additional times.
Detecting leaks — Once the system is evacuated, the vacuum pump is valved off. If the system pressure begins to rise according to the micron gauge, there is a leak.

14. Terminology
Cleaning — Contaminants form within the system from the mixture of moisture, acid, and oil. This buildup results in sludge. Sludge cannot be removed from the system using a vacuum pump. Standard cleanup procedures using filter-driers should be used.

15. Terminology
Vacuum pump — The machine at the heart of the evacuation process, the vacuum pump lowers the pressure inside of the system to below atmospheric pressure, causing water vapor to boil off and vent to the atmosphere. The contaminants from the system being evacuated end up in the vacuum pump’s oil. It is necessary to periodically change this oil.

16. Terminology
Single- and two-stage vacuum pumps are most commonly used in the field today. The two-stage model pulls a deeper vacuum because the first stage exhaust is actually vented into the second stage intake. This allows second stage to pull at a lower pressure, increasing efficiency and reducing the vacuum.
Vacuum pumps are rated in cubic feet per minute (cfm). Three- to 6-cfm pumps are typically used in residential applications.

17. Vacuum Pumps Terminology A rule of thumb
The CFM rating squared of a vacuum pump equals its maximum system tonnage.
For example: A 7 CFM pump is rated for a 49 ton system, a 3 CFM pump is rated for a 9 ton system
Use the large vacuum port to achieve these pump capabilities
Vacuum Pumps

18. Terminology
Electronic vacuum gauge — Sometimes referred to as a micron gauge, the electronic vacuum gauge reads in units of microns, and it is the most accurate method of measuring a vacuum.

19. The Purpose of “Evacuating” a Refrigeration System
Evacuating a refrigeration system serves two primary objectives:
1. It removes noncondensables.
2. It dehydrates (removes water vapor).

20. The Purpose of “Evacuating” a Refrigeration System
If noncondensables such as air are not removed, the system will operate at higher than condensing pressures. This happens because the air is trapped at the top of the condenser, effectively reducing the condenser capacity.
Increasing the condensing pressure results in higher compression ratios and higher discharge temperatures, both of which decrease system efficiency and can lead to decreased reliability.

21. The Purpose of “Evacuating” a Refrigeration System
Non condensable can and will cause damage to the compressor.
Broken scroll plates
Broken push rods, pistons, values and shafts
Takes up space in condenser
Water can also cause motor damage
Moisture + Heat + Oil = Acid
Why a Good Vacuum?

22. The Purpose of “Evacuating” a Refrigeration System
These Non condensable will also effect
The capacity and the efficiencies of the unit
If moisture also present, can restrict metering devices
Causes Higher than normal Head Pressures
Why a Good Vacuum?

23. The Purpose of “Evacuating” a Refrigeration System
Does evacuation actually pull liquid water out of the system?
No, evacuation will not pull liquid water out of the system. When you evacuate a system you are actually dropping the pressure sufficiently to allow water to “boil” at room temperature. As the water boils, it of course changes to the vapor state, and this vapor is drawn out by the vacuum pump.

24. The Purpose of “Evacuating” a Refrigeration System
How low a vacuum do I need to properly evacuate a system?
Modern deep vacuum pumps should be used for this purpose. These pumps have the ability to evacuate down to 20 microns in field situations.
Equipment manufacturers should be consulted to determine their recommended vacuum levels. However, if a vacuum of 500 microns can be achieved, that is usually considered adequate.

25. The Purpose of “Evacuating” a Refrigeration System
Care must be taken to assure that the vacuum measured at the gauge is equal to the vacuum level in the system being evacuated.
Use as large a hose as possible to connect the evacuation equipment to the refrigeration system.

26. The Purpose of “Evacuating” a Refrigeration System
It is also advisable to remove any Schrader cores prior to connecting evacuation lines so as to eliminate large pressure drops.
Once the system is evacuated, it is also advisable to isolate the pump from the system and observe if the system holds its low vacuum.

27. The Purpose of “Evacuating” a Refrigeration System
Some increase is acceptable (up to about 1000 microns), but if the system vacuum level exceeds that, a second and even third evacuation may be needed.
If during the equalization time the system vacuum level goes back to atmospheric, it is an indication that a leak is present.

28. The Purpose of “Evacuating” a Refrigeration System
If a vacuum pump is no longer able to pull a deep vacuum, it is usually an indication that the oil in the pump is contaminated and must be replaced.
Be sure to use oil specifically produced for vacuum pump applications.

29. The Purpose of “Evacuating” a Refrigeration System
This oil has a much lower vapor pressure than conventional oils.
It is advisable to replace the vacuum pump oil at regular intervals, usually after each use, to make certain a low vacuum level can be achieved.
The oil should be replaced while still warm, enabling better drainage.

30. The Purpose of “Evacuating” a Refrigeration System
More On A Micron
A micron is a metric measure and is defined as 1 millionth of a meter or 1 thousandth of a millimeter.
Most service techs think of a perfect vacuum as 30 inches of mercury (Hg). The last inch (from 29-30) of vacuum is equal to 25,400 microns. The micron then is a much more precise method for measuring deep vacuums.
1 micron = mm Hg

31. The Purpose of “Evacuating” a Refrigeration System
Your pump might be able to pull a 50-micron vacuum, but you never want to evacuate a system too low because compressor oil boils at about 200 microns

32. Evacuation Levels
The degree of vacuum achieved and the time required to obtain the specified moisture level are a function of
(1) the type and size of vacuum pump used,
(2) the internal volume of the component or system,
(3) the size and composition of water-holding materials in the system,
(4) the initial amount of moisture in the volume,

33. Evacuation Levels (5) piping and fitting sizes,
(6) the shape of the gas passages,
(7) the external temperatures maintained and
(8) the maintenance of the evacuation system.

34. Factors That Influence Evacuation Speed
Evacuation Levels
Factors That Influence Evacuation Speed
Internal volume of the system
Amount of moisture within the system
Ambient temperature
Amount of internal restrictions
Amount of external restrictions between the system & vacuum pump
Size of vacuum pump

35. Suggestions on Speeding Up The Process
Evacuation Levels
Suggestions on Speeding Up The Process
Pull vacuum through both sides of the system
The connection line between the vacuum pump and system should be as short as possible
The hose diameter should be as large as possible
Remove schrader valves
Replace vacuum pump oil after every evacuation
On large systems, use two vacuum pumps

36. Charging Hoses –Versus- Vacuum Hoses
Use a larger I.D. high vacuum hose (non permeable) when evacuating a system not a standard charging hoses.
Standard charge and testing hoses are small I.D. dimensions and designed for positive pressure not deep vacuums.
Use High Flow port on your vacuum pump
Copper tubing is your better choice but is not practical

37. Evacuation Levels
Deep Vacuum

38. Evacuation Levels Deep Vacuum
That at less a 500 microns vacuum be pulled and held for 15 minutes below 1000 microns
Once this vacuum is reached the vacuum pump should be mechanically isolated form the system and shut off
The vacuum thermistor gage should be located between the isolation value and unit

39. Evacuation Levels
The system should hold the vacuum for at less 5 minuets longer is better
Some sources recommend 10 to 15 minuets
The micron level should not rise above 1000 micron during this time
If you can pull a deeper vacuum and hold for a longer time this is always better

40. Evacuation Levels

41. Evacuation Levels

42. Evacuation Levels

43. Deep Evacuation Shut off pump valve
Gauge Manifold
Start Pump and open valves on Gauge Manifold
500
Vacuum Pump
Continue Vacuum to 500 microns
Wait 5 min. to see if proper vacuum remains
Turn off pump
System Ready for Charging
CONDENSER
Compressor
EVAPORATOR
Receiver
TEV
Sight Glass
Filter-Drier

44. Evacuation Levels
Triple Evacuation

45. Evacuation Levels
The triple Evacuation method is one recommended procedure to pull a vacuum
Pull a vacuum ( break atmosphere)
Break vacuum with dry nitrogen
Pull second vacuum to at least microns
Break with dry nitrogen
Pull third vacuum to 500 microns or less and hold for 15 minutes.

46. Evacuation Levels

47. Evacuation Levels

48. Triple Evacuations : Step 1
NITROGEN
Break vacuum to about 2 psig
Close valve to pump,
open valve to nitrogen
Pull 1st vacuum to 500 microns
Nitrogen removes moisture
Vacuum Pump
500
CONDENSER
Compressor
EVAPORATOR
TEV
Sight Glass
Receiver
Filter-Drier

49. Triple Evacuations: Step 2
Close valves to nitrogen tank
Open valve to pump
Pull 2nd vacuum to 500 microns
Vacuum Pump
500
NITROGEN
NEVER start a compressor in a vacuum
CONDENSER
Compressor
EVAPORATOR
TEV
Sight Glass
Receiver
Filter-Drier

50. Triple Evacuations: Step 2
Break vacuum with nitrogen
Vacuum Pump
500
NITROGEN
CONDENSER
Compressor
EVAPORATOR
TEV
Sight Glass
Receiver
Filter-Drier

51. Triple Evacuations: Last Step
Pull 3rd vacuum to 500 microns
Vacuum Pump
500
NITROGEN
CONDENSER
Compressor
EVAPORATOR
System Ready for Charging
TEV
Sight Glass
Receiver
Filter-Drier

52. How Can I Select The Right Pump CFM?
System size (tons)
Pump cfm
1-10
1.5
10-15
2.0
15-30
4.0
30-45
6.0
45-60
8.0
60 and above
11.0

53. When Should I Evacuate?
Any time a refrigeration system is opened to the atmosphere, it must be completely evacuated before refrigerant can be added back into it.
Proper evacuation of a system is an important part of the overall repair process. It ensures that no atmospheric air remains in the system.

54. Evacuating a system can be a time-consuming process, and to do the job properly, it should not be rushed.
Proper planning will allow a technician to handle other tasks during the evacuation process.

55. How To Speed Up The Evacuation Process

56. How To Speed Up The Evacuation Process

57. How To Speed Up The Evacuation Process
Size Does Matter!!

58. How To Speed Up The Evacuation Process
Example
The following you are using a 1.3 CFM, 2-stage, direct drive vacuum pump.
It also assumes you are using 1/4" copper tubing between the vacuum pump and the system.

59. How To Speed Up The Evacuation Process
Length of Tubing        Vacuum (Microns)  Time in Minutes 10                      50                                             50                                             50                                             50                                             50                     

60. How To Speed Up The Evacuation Process
Example
The following you are using a 1.3 CFM, 2-stage, direct drive vacuum pump.
It also assumes you are using 3/8" copper tubing between the vacuum pump and the system.

61. How To Speed Up The Evacuation Process
Length of Tubing        Vacuum (Microns)  Time in Minutes 10                      50                                             50                                             50                                             50                                             50                     

62. Here Is Some Data Regarding The Schrader Core
How To Speed Up The Evacuation Process
Here Is Some Data Regarding The Schrader Core

63. How To Speed Up The Evacuation Process
Example:
A 500 micron vacuum was pulled on a 25lb refrigerant tank using a 3CFM vacuum pump

64. How To Speed Up The Evacuation Process
Here are the times required with and without the core removed:
Core depressed: minutes Core removed: 2.92 minutes

65. Driers - Dehydration

66. Driers - Dehydration

67. Driers - Dehydration

68. Driers - Dehydration

69. Quite a difference!
Now You Probably Know More Than The Regular Service Tech About Evacuation & Dehydration

70. Are There Any Other Questions?

71. Let’s Put The Training To Use

72. Thank You For Your Interest & Participation