Liquid charging is always done via the liquid-line service valve. Vapor charging is done via the suction service valve. In systems that use water in any part or component, it becomes necessary to initiate the charging process with vapor charging.
Pure refrigerants like R22 can be added in liquid or vapor states. If adding liquid into the suction like, throttle it in slowly to avoid slugging the compressor or diluting and washing out the compressor oil. After the charge has been set, avoid installing the gauges as part of regular service.
R-410A must be charged as a liquid. Refer to the instructions printed on your refrigerant cylinder to verify that the cylinder is oriented properly for charging. Charging as a gas may result in refrigerant separation and improper unit operation.
The R-134a refrigerant used in car air conditioners would normally be a gas (it boils at a frigid 15 degrees below zero). If you compress it and pressurize it enough, though, it turns into a liquid. The compressor in your vehicle's A/C does exactly that, so you have liquid R-134a pumping through part of the A/C system.
Liquid charging means filling the system back with liquid refrigerant. It is faster and saves time. We can initiate charging a system with liquid refrigerant in appliances that do not use water in any part/component. These are air-cooled systems.
It is difficult to melt the ice, and at times the evaporator/condenser coils rupture and burst due to ice. This is dangerous and must be avoided. This is the reason that a chiller system is always first charged with vapor refrigerant.
The most widely quoted rule of thumb is the 100˚ – 110˚ over ambient discharge rule. This guideline states that a properly charged unit will have a discharge line temperature of 100˚ – 110˚ above the outdoor temperature.
The larger line typically carries a cool gas and is insulated. This is commonly referred to as the suction line, but it is also called the return line or vapor line. The smaller uninsulated line typically carries a warm liquid. It is most often called the liquid line.
That is to say, non-azeotropic refrigerants must be added with liquid, and non-azeotropic refrigerants all start with R4, which needs to be added as a liquid. Common non-azeotropic refrigerants like R401A, R403B, R404A, R406A, R407A , R407B, R407C, R408A, R409A, R410A, R41A.
The refrigerant gets inserted into the low-pressure side of the system, not the high-pressure side. Both the low side and the high side ports are attached to the compressor, which is found under the hood of your car. The low side port is the larger tube.
Liquid recovery is fast, but not all equipment can handle the process. Vapor recovery is slower, but is the most common recovery method used. The push-pull recovery method works best when recovering more than 10 pounds of refrigerant. all of your R-410A tanks and have them re-certified every five years.
So, now I must admit that the better way to do it is to open the SUCTION valve first (slowly!). That prevents oil loss out of the compressor into the discharge line and out of the liquid line.
Airflow Problems
Without airflow, heat doesn't get to the evaporator coil, and the refrigerant doesn't boil. As a result, the pressure and the temperature will drop, causing the system to freeze. If the filter you're using is too restrictive, it can cause the same problem.
Connect R22 manifold gauge middle hose onto R22 refrigerant container. Flip R22 container upright and open the valve. Watch left and right gauges to see when pressure equalizes.
Most people assume if their A/C is blowing warm that they are low on refrigerant. However, this is not always the case. Therefore, when charging A/C systems it is recommended to evacuate the system before adding refrigerant.
The purge unit is located at the top of the condenser coils. The refrigerant is sucked into the purge unit from the top of the condenser. The refrigerant free from air and moisture is then sent to the evaporator through the expansion valve.
The compressor creates a pressure differential, resulting in high pressure on the high side (discharge line, condenser, and liquid line) and low pressure on the low side (suction line, evaporator, and expansion line).
In some cases, overcharging your system can cause damage, inefficient cooling, and deterioration in your AC unit.
Freon costs $50 to $150 per pound to refill a home AC and $4 to $21 per pound when buying wholesale. A 25lb tank of R410A costs $75 to $200. *Most central air conditioners need 2 to 4 pounds to recharge the refrigerant.
All new compressors from Classic Auto Air contain a full system charge of oil. Do not use more than 24 oz. of 134A refrigerant! 1.5 lbs. or 24 oz of R134A is what is required.
If the liquid refrigerant doesn't do direct damage to the valve structures, it will do indirect damage to the internal drive components of the compressor when it dilutes the crankcase's oil and degrades its lubricity.
For systems under a vacuum, once the desired vacuum level has been reached, the vacuum pump has been isolated from the system, and no leaks exist, always charge liquid refrigerant in the high side of the system until high- and low-side pressures equalize and liquid stops flowing.