View pricing, availability, product information and place orders online 24/7 at singlesource.mingledorffs.com

HVAC and Plumbing Distributor
Bubba Moore

Bubba Moore

Technical Services Manager
Southeast District

Evacuation and Dehydration Methods

HVAC evacuation techniques are meant to remove air and moisture trapped in a refrigeration system. Air takes up space in the refrigeration system and causes reduced heat transfer plus erratic operations. On the other hand, moisture in the refrigerant system can freeze-up and block refrigerant flow. Moisture also combines with the oil and refrigerant to form acids and sludge, which can cause system damage or failure.

There are a couple of HVAC evacuation methods that are used. They are the deep vacuum method and the triple vacuum method.

The Deep Vacuum Method

The deep vacuum method relies on evacuation to dehydrate moisture from the refrigeration system. A deep vacuum is any vacuum of 500 microns or less. As the vacuum reduces pressure, the boiling point of water is also reduced. During this time of the deep vacuum the ambient temperature surrounding the system needs to be higher than the boiling point of the moisture in the system. For example, at a vacuum of 5,000 microns, liquid water will boil off anywhere in the refrigerant system where the temperature is 35 degrees or higher.

HVAC and Plumbing Distributor

Deep Vacuum Method Chart

How do you know the system has been adequately evacuated? First, the system needs to be vacuumed to 500 microns or below, then it is isolated from the vacuum pump. Now the vacuum gauge needs to be monitored to see if there are any changes in the level of vacuum in the system. If the vacuum gauge shows a pressure rise and the pressure continues to rise without leveling off, a leak exists somewhere and needs to be located and repaired.

If the vacuum gauge shows a pressure rise and levels off between1,000 and 2,000 microns within seven minutes, the system is leak free but still too wet. A constant reading on the vacuum gauge of 500 to a 1,000 microns within seven minutes indicates a tight leak free dry system.

The Triple Vacuum Method

The triple evacuation method can take about three hours when performed as recommended. The system is first evacuated to 5,000 microns during the first and second evacuations. Between the evacuations, the system is pressurized with dry nitrogen to about 10 psig and allowed to sit for an hour so the nitrogen can absorb the moisture. For the third and last evacuation, a deep vacuum of 500 microns is preformed and the system is monitored in the same manner described for the deep vacuum method.

HVAC and Plumbing Distributor

Triple Vacuum Method Flow Chart - HVAC Evacuation

The deep vacuum and triple vacuum methods are both used frequently to evacuate and dehydrate refrigeration systems. The deep vacuum method is normally used when new equipment is installed or the refrigeration system was opened for a repair. The triple vacuum method is usually done and recommended, if the system is especially wet or after contaminants are found in the refrigerant system.

These evacuation procedures help protect and can extend the life of a system.

Facebook
Twitter
LinkedIn
Email
Print

More to explore

Native American Heritage Month

November is Native American Heritage Month November represents a time to celebrate the rich cultures and traditions as well as acknowledge the

Because I was Inverted

For this article, I will explain how to replace the main control board on a 38MARB ductless outdoor unit. The boards are

coil cleaner

Cleaning Coils

Fall is the time for the leaves to fall and with the mixture of rain and wind tends to stir up debris

HVAC Evacuation

Alabama Locations

Anniston (256) 241-3026 105 E D St, Anniston, AL 36201
Auburn (334) 734-8011 2295 1st Ave, Opelika, AL 36801
Birmingham (205) 250-7714 516 31st St N, Birmingham, AL 35203
Dothan (334) 836-1035 205 Wedgewood Dr, Dothan, AL 36303
Gulf Shores (251) 968-2660 820 Commerce Dr, Gulf Shores, AL 36542
Huntsville (256) 859-2691 391 Nick Fitcheard Rd NW, Huntsville, AL 35806
Loxley (251) 964-2707 30020 Co Rd 49, Loxley, AL 36551
Mobile (251) 476-2220 5522 W Commerce Blvd West, Mobile, AL 36619
Montgomery (334) 262-4855 861 Plantation Way, Montgomery, AL 36117
Muscle Shoals (256) 383-6904 107 Commerce St, Muscle Shoals, AL 35661

Georgia Locations

Albany(229) 432-5254205 Baldwin Dr, Albany, GA 31707
Athens(706) 548-2563105 Whitetail Way, Bogart, GA 30622
Atlanta(404) 875-77551290 Tacoma Dr NW, Atlanta, GA 30318
Augusta(706) 651-19503618 Wrightsboro Rd, Augusta, GA 30909
Brunswick(912) 265-5193275 Rose Dr, Brunswick, GA 31520
Columbus(706) 322-38706201 W Hamilton Park Rd, Columbus, GA 31909
Conyers(770) 918-9132335 Gees Mill Business Pkwy NE, Conyers, GA 30013
Forest Park(404) 361-24745158-C Kennedy Rd, Forest Park, GA 30297
Gainesville(770) 297-93352472 Hilton Dr, Gainesville, GA 30501
Lawrenceville(678) 442-10602111 Cedars Rd SE, Lawrenceville, GA 30043
Lithia Springs(770) 948-3451320 Thornton Rd #106, Lithia Springs, GA 30122
Macon(478) 474-85445527 Thomaston Rd, Macon, GA 31220
Marietta(770) 426-05511060 Triad Ct, Marietta, GA 30062
Newnan(770) 239-210570 Enterprise Ct, Newnan, GA 30265
Peachtree Corners(770) 239-21006675 Jones Mill Ct, Peachtree Corners, GA 30092
Savannah(912) 232-1228103 Central Jct Blvd, Savannah, GA 31405
Statesboro(912) 764-8841126 W Parrish St, Statesboro, GA 30458
Valdosta(229) 245-8200363 Connell Rd, Valdosta, GA 31602
Warner Robins(478) 953-3727110 Byrd Way, Warner Robins, GA 31088

South Carolina Locations

Hilton Head(843) 689-34043715, 21 Hunter Rd, Hilton Head Island, SC 29926

Florida Locations

Fort Walton Beach(850) 244-201776 Beal Pkwy SW, Fort Walton Beach, FL 32548
Panama City(850) 913-05853012 Lisenby Ave, Panama City, FL 32405
Pensacola(850) 438-10054405 N. Palafox Street, Pensacola FL 32505

Mississippi Locations

Hattiesburg(601) 579-96701851 Lincoln Rd, Hattiesburg, MS 39402
Ocean Springs(228) 497-5090Sunplex Industrial Park, 5717 Suntec Drive, Ocean Springs, MS 39564

Commercial Sales

Norcross – North Georgia Hub
(800) 282-4911

Birmingham – North Alabama Hub
(205) 250-7714

Macon – Southwest Hub
(800) 342-9250

Loxley – Gulf Coast Hub
(800) 239-7419

Savannah – Southeast Hub
(800) 822-7617

Commercial Parts

 CompanyWeb AddressDescription
Airzonewww.airzoneinc.comCustom and Underfloor Air Handlers
Aladdin Metal Productswww.aladdinmetalproducts.comCurb Adapters and Roof Curbs
Aprilairewww.aprilaire.comIndoor Air Quality Products
Autaniwww.autani.comBuilding Automation and Controls
Bardwww.bardhvac.comHeat Pumps,Gas/Electric, and Wall Mounted Air Conditioners
Bryantwww.bryant.comCommercial, Industrial, Residential Heating & A/C Products and Controls
Carrierwww.commercial.carrier.comCommercial and Residential Heating & A/C Products
Data Airewww.dataaire.comPrecision Air Control for Data Processing Centers
 DXairwww.dxair.comPool dehumidification systems
 First Companywww.firstco.comFan Coil Units
Global Plasma Solutionswww.gpshvac.comAir Purification and Bi-Polar Ionization
 Greewww.greeusa.comPTACs
 Hayes Fluid Controlswww.haysfluidcontrols.comHose Kits and Control Valves
 iAirewww.myiaire.comCommercial Air Purification using ionization with energy savings
 IslandAirewww.islandaire.comPTACs, Vertical Units, Water Source Heat Pumps
 i-Vuwww.commercial.carrier.comBuilding Automation and Controls
 Magic Airewww.magicaire.comFan Coil Units
 Micro Metlwww.micrometl.comRoof Curbs, RTU Accessories, & ERVs
 Modinewww.modine.comGas-Fired Unit Heaters, Duct, Furnaces, Hot Water Cabinet Unit Heaters, Makeup Air, and Dedicated Outdoor Air Systems
 Network Thermostatwww.networkthermostat.comInternet Thermostats, Wifi Themostats, Ethernet Thermostats
Paynewww.payne.comResidential Heating & A/C Products
Rawal Deviceswww.rawal.comContinuous Capacity Modulation and Dehumidification for DX Systems
Renew Airewww.renewaire.comFixed-Plate ERVs
Totalinewww.totaline.comCompressors, Parts, and Supplies
United CoolAirwww.unitedcoolair.comModular All-Indoor HVAC Systems
 Warren Technologywww.warrenhvac.comElectric Heaters
 Wilo Pumpswww.wilo-usa.comPump Systems for HVAC and Water Supply and Sewage