Evacuation & Dehydration Seminar Presented by:

Use Safety Equipment

Remove Jewelry

Lift and Move Correctly

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

Codes Follow all Local Codes. In the absence of local codes, consult the current edition of the National Fuel Gas Code. 7

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

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

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

Noncondensables — Gases that will not condense in the condenser. Terminology Micron — One thousandth (1/1,000) of a millimeter or 0.00004 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.

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.

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.

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.

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.

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.

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

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.

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).

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.

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?

The Purpose of “Evacuating” a Refrigeration System

The Purpose of “Evacuating” a Refrigeration System

The Purpose of “Evacuating” a Refrigeration System

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?

The Purpose of “Evacuating” a Refrigeration System Why a Good Vacuum?

The Purpose of “Evacuating” a Refrigeration System Why a Good Vacuum?

The Purpose of “Evacuating” a Refrigeration System Why a Good Vacuum?

The Purpose of “Evacuating” a Refrigeration System Why a Good Vacuum?

The Purpose of “Evacuating” a Refrigeration System Why a Good Vacuum?

The Purpose of “Evacuating” a Refrigeration System

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.

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.

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.

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.

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.

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.

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.

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 = 0.001 mm Hg

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

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,

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.

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

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

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

Evacuation Levels Deep Vacuum

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

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

Evacuation Levels

Evacuation Levels

Evacuation Levels

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

Evacuation Levels Triple Evacuation

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 1000-800 microns Break with dry nitrogen Pull third vacuum to 500 microns or less and hold for 15 minutes.

Evacuation Levels

Evacuation Levels

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

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

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

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

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

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.

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.

How To Speed Up The Evacuation Process 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, (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.

How To Speed Up The Evacuation Process 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

How To Speed Up The Evacuation Process

How To Speed Up The Evacuation Process

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

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.

How To Speed Up The Evacuation Process Length of Tubing        Vacuum (Microns)  Time in Minutes 10                      50                      88 6                       50                      54 3                       50                      28 2                       50                      22 1                       50                      13

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.

How To Speed Up The Evacuation Process Length of Tubing        Vacuum (Microns)  Time in Minutes 10                      50                      19 6                       50                      15 3                       50                      9 2                       50                      6.5 1                       50                      4.5

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

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

How To Speed Up The Evacuation Process Here are the times required with and without the core removed: Core depressed: 23.25 minutes Core removed: 2.92 minutes

Driers - Dehydration

Driers - Dehydration

Driers - Dehydration

Driers - Dehydration

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

Are There Any Other Questions?

Thank You For Your Interest & Participation