Vacuum pump is another important tool, without which professional results impossible. If the system is only open to the atmospheric pressure within a short period of time, the so-called method purge the system is used. This method uses the refrigerant itself to remove air that may be in the system. Refrigerant, being heavier than air it displaces the air. If the system was open to the atmosphere for a long time, purging will not be satisfactory. It is in this situation that the effective vacuum pump should be used. Cleaning-introduction of the refrigerant through the suction side of the system, allowing him to reach the highest part of the compressor. The refrigerant must be allowed to flow long enough for the air to be driven out by the refrigerant.
The collector and the sensors are connected to the vacuum pump centre hose on the manifold. On the low side of the hose hooks on the low side of the system, the party of the high-pressure hose of high side of the system. The system should not have any pressure in the vacuum pump on the hook.
Pressure in the system can lead to the removal of oil from the vacuum pump. On the low side of the measuring device must show pressure drop short time after the pump pressure of 70 MPa. If you look in the right part of the chart you will see the temperature in degrees Fahrenheit lines that fall from the left digit of the reference lines. Looking down on a diagonal to the left until the line crosses the 70-psi-line. You can see that this intersection is at a 40-degree line. This should be the actual temperature at the compressor suction line. This temperature is measured with a thermometer. If suction temperature is higher than reading, the refrigerant should be added. If suction temperature is lower than read, some of the charge should be removed from the device. Table 26-1 graph, chart is used. Another manufacturer uses charging chart, as shown in Table 26-2.
Charging to the touch method is quickly becoming a thing of the past. This can be done by a specialist with extensive experience, installed in the system. Bad is the glass that inexperienced specialist can overcharge the system tries to clean the bubbles or flash from the sight glass. Such experts studied wrong to charge the system until the sight glass is clear. If the ammeter was used during the load test, excessive current will be visible. If the system " and"limitation of the filter-dehydrator, bubbles or outbreaks can occur in the sight glass. If the heat load on the system and its operation at temperatures above rated temperature, flashing in the sight glass happen. Example: you check the condensing unit of a 40-foot by 60-foot by 15-foot walk-in refrigerator. Sight glass flashes. Unknown to you, the local beer supplier delivers its weekly enjoy a beer in the shop. A box of beer holding the door open so that he may enter and leave with his handtruck relaxed. Evaporator fans pulling air from outside the conditioned space over them. Hot wet air causes the heat load on the evaporator higher than it was designed for. You can see in the situation above, that device is displayed in the operating low on refrigerant; however, as soon as the door was closed, and the device works as intended, sight glass and it will be clear. That there will be an excessive amount of refrigerant in the system, if it was done in the above example? The device will be overstated and, ultimately, damage and destruction to happen. If the ammeter is used, and he reads the maximum amperage for the block, there's still something wrong with the device in addition to low refrigerant.