Our ever expanding list of articles on HVAC/R products and processes will help you get more performance out of your tools, and more time out of your day. The Evacuation and Charge Process A vacuum pump is used to remove air and contaminants from an HVAC system, creating a vacuum state. It is important to note that a vacuum pump is not a recovery unit. A recovery unit should always be used to make sure the refrigerant is recovered from the system before you begin the vacuum process. A vacuum can help protect your system from contaminants and non-condensable gases, which can damage HVAC system components, reduce system efficiency and even cause failure. A vacuum pump “pulls” air, moisture and contaminants out of the system after it has been repaired and before it is recharged. The deeper and more complete the vacuum, the more contaminants trapped within the system components and even in the compressor oil are removed. Prior to pulling a vacuum and charging an HVAC system, you’ll want to recover, repair and check for leaks.

Assuming that these items have been checked off your list, you’re ready to safely evacuate.prices of ac units for home Before starting, fill the vacuum pump with vacuum oil. how to hide indoor air conditioner unitRemove the cap, open the fitting and begin pouring. new ac unit runs constantlyKeep pouring the oil until the oil level reaches the oil line. Here you’ll benefit from a large oil fill port and sight glass, which gives you the benefit of being able to see when the oil reaches the appropriate level. It is important to note here that the quality of your vacuum pump performance is directly related to the quality of your vacuum pump oil. The cleaner your oil, the better your pump’s performance. We recommend high vacuum mineral-based oil be used in all pumps regardless of the type of oil that is used in the system.

Once you can see through your sight glass that you’ve reached the proper oil level, put the fittings back on, or, if desired, attach the exhaust filter. Remove the Schrader cores (if present) with the core removal tools. Install the test and charging manifold. Connect the hoses from the manifold to the system.  Connect the low side (or blue hose) to the low side core removal tool and high side (or red hose) to the high side core removal tool. If you’re using a four-valve manifold, connect the 3/8” hose from the vacuum port on your manifold to the 3/8” port on the vacuum pump. Connect the 4th hose from the manifold to the refrigerant cylinder. If you are using an extension cord, make sure you are using the proper gauge for your pump. Plug in the power cord for the pump. Open all manifold valves and make sure the vacuum valve and core removal tool ball valves are open.For cold weather starts, open the intake port until the pump reaches running speed and then close it off.

You are now pulling a vacuum. It is important that the oil level remain steady when the pump is running for proper operation – about 1/2 to 5/8 up in the sight glass. If it falls too low, the vacuum pump could be damaged. If it’s too high, it will increase the oil in the exhaust. Once you have pulled a vacuum that meets the manufacturer’s specifications, you can close the valves on the core removal tools. Observe the vacuum gauge. It is normal operation for a rise in microns to occur. However, if the rise continues to atmosphere (760,000 microns), there is a leak in the system. Check the system manufacturer’s recommendation for tolerance. Once you are satisfied with the reading, close the valve that connects the manifold to the pump. You can now shut off and disconnect the vacuum pump. Your evacuation process is complete and you are ready for system charge. To charge, open the valve on the refrigerant cylinder. Add enough refrigerant to create a small positive pressure in the system – about 3 psi on the low side.

Remove the digital vacuum gauge and complete the charging process per the manufacturer’s specifications. Once the charge is complete, you can replace the valve cores and remove the vacuum valve and core removal tools. It’s a good idea to simply replace Schrader valves, as they are not that expensive and new valves will reduce the likelihood of system leaks. Screw them back in and seat them properly. Remove your tools and you are ready to go. Connect a digital vacuum gauge for accurate vacuum measurement. The best place to measure vacuum is at the system, not at the pump. With a combination vacuum and charging valve on your core removal tool, you can attach the electronic vacuum gauge directly to the system and isolate it from the pump, hoses and manifold for a true indication of the vacuum in the system. If you suspect an open or wet system, be sure to use the gas ballast feature on your vacuum pump. The gas ballast prevents water vapor from condensing in the vacuum pump oil by introducing a small amount of fresh air into the pumping chamber.

Open the gas ballast just slightly and then begin to watch your electronic vacuum gauge. If the vacuum stays at a consistently high level of microns or doesn’t pull down below 5,000 microns, your system still contains contamination or has a leak. Repair the leak before proceeding. A way to speed the vacuum process is to use a heat gun. This warms the molecules and gets them to leave the surface sooner, speeding the flow of vapor molecules to the pump. Remember to be careful because they do get hot and will take paint off systems.Refrigeration and air-conditioning end-uses typically use a refrigerant in a vapor compression cycle to cool and/or dehumidify a substance or space, like a refrigerator cabinet, room, office building, or warehouse. Chillers typically cool water, which is then circulated to provide comfort cooling throughout a building or other location. Chillers can be classified by compressor type, including centrifugal, reciprocating, scroll, screw, and rotary compressors.

Chillers used to cool industrial processes are included under Industrial Process Refrigeration. Cold storage warehouses store meat, produce, dairy products, and other perishable goods. The majority of cold storage warehouses in the United States use ammonia as the refrigerant in a vapor compression cycle, although some rely on other refrigerants. Commercial ice machines are used in commercial establishments (e.g., hotels, restaurants, convenience stores) to produce ice for consumer use. Ice machines produce ice in various sizes and shapes, and with different retrieval mechanisms (e.g., dispensers or self-retrieval from bins). Ice makers that are part of a refrigerator-freezer are considered part of the latter end-use, while equipment that is solely used to make ice, even if used in a domestic setting, is considered part of the commercial ice machine’s end-use. Household Refrigerators and Freezers Household refrigerators and freezers are intended primarily for residential use, although they may be used outside the home.

Household freezers only offer storage space at freezing temperatures. Products with both a refrigerator and freezer in a single unit are most common. Small refrigerated household appliances may also include chilled kitchen drawers, wine coolers, and mini fridges. Ice skating rinks are used by the general public for recreational purposes and also include professional rinks. These systems frequently use secondary loop refrigeration systems. Industrial Process Air Conditioning Industrial process air-conditioning units, which are distinct from commercial and residential air conditioning, provide comfort cooling for operators and protect process equipment. This end-use is often used when ambient temperatures approach 200°F (93°C) and corrosive conditions exist. Industrial process refrigeration systems cool process streams in industrial applications. The choice of substitute for specific applications depends on ambient and required operating temperatures and pressures.

Motor Vehicle Air Conditioning Motor vehicle air-conditioning systems (MVACs) provide comfort cooling for passengers in light-duty cars and trucks, buses, trains, and other forms of transportation. Non-Mechanical Heat Transfer Systems Non-mechanical heat transfer systems include cooling systems that do not rely on a vapor compression cycle, such as those using convection to remove heat from an area. Two types of such systems are recirculating coolers, i.e., systems with fluid pumps, and thermosiphons, i.e., those that rely on natural convection currents. This end-use also includes Organic Rankine Cycle (ORC) devices that typically pump refrigerant to recover and utilize energy from lower-temperature heat rejected from other processes. Residential and Light Commercial Air Conditioning and Heat Pumps This end-use includes equipment that cools enclosed spaces in households and commercial industries, but excludes chillers―which include room air conditioning such as window units, packaged terminal air conditioners (PTAC) and heat pumps (PTHP), and portable air conditioners;

central air conditioners (i.e., ducted); non-ducted systems (both mini and multi splits); water-source and ground-source heat pumps; Residential and light commercial air conditioning and heat pumps are often distinguished from chillers by the fact that they condition the air directly, rather than cool (or heat) water that is then used to condition air. Residential dehumidifiers are primarily used to remove water vapor from ambient air or directly from indoor air for comfort or material preservation purposes. While air-conditioning systems often combine cooling and dehumidification, this application serves only the latter purpose. Refrigerated transport moves products (e.g., perishable goods) from one place to another by various modes of transportation while maintaining necessary temperatures, including refrigerated ship holds, truck trailers, railway freight cars, ships, and other shipping containers. Retail food refrigeration, or commercial refrigeration, includes equipment designed to store, display, process, or dispense chilled or frozen goods for commercial sale.