Note.
- A relatively large leak can be found, for example, by feeding purified and dried compressed air or nitrogen under a pressure of no more than 15 bar into the refrigerant circuit. If the leak is large enough, the leak location can be found by the noise made by the air or gas escaping there.
- Compressed air or nitrogen should be supplied through the service port.
1. The quick-release adapter for service nipples can be connected to the STOA compressor unit, for example, using a modified filling hose "A" (e.g. with a 5/8"-18 UNF thread, depending on the thread on the adapter) and a suitable adapter "B". In order to prevent moisture, oil and dirt from the STOA compressor unit from getting into the refrigerant circulation circuit of the air conditioning system, in addition to the oil-dirt-water separator of the compressor unit, usually used in painting, you should use, for example, a combined fine filter, installing it between the compressor unit and the filling hose "A".
2. Through a block of pressure gauges with a reducer for nitrogen (rated for maximum pressure: 15 bar) "1" and filling hose "2" (e.g. with 5/8"-18 UNF thread) to service nipple (to which the quick-release adapter for service fittings was connected) a closed refrigerant circulation circuit can be connected to a gas cylinder "3" with nitrogen.
3. Slowly increase the pressure in the refrigerant circuit to a maximum of 15 bar.
Attention.
- Maximum working pressure: 15 bar.
- Therefore, when searching for a leak using nitrogen, work only with a reducer for nitrogen cylinders.
4. Find the leaky area by the noise made by the gas escaping there, or with the help of an ultrasonic detector "V.A.G 1842".
5. Displace the nitrogen with purified and dried compressed air from the refrigerant circuit. Nitrogen must not enter the service cylinder. Reason: Because of this, the service cylinder is filled with non-condensable gases.
Text copied from this resource SKODABOOK.RU
6. Eliminate leaks.
7. Perform a vacuum and recheck with a vacuum gauge for several hours. Only if the vacuum is maintained can you begin filling.
8. If there is a leak through which air does not penetrate or penetrates almost not, and the air conditioning servicing stand manages to create sufficient vacuum: The vacuum gauge readings do not increase or increase very slowly after the stand is switched off, indicating that air penetrates and the vacuum is lost only through a very small leak.
9. Fill the circulation circuit with 100 grams of refrigerant, use an electronic leak detector to find the location of a possible leak and eliminate the leak; or fill the circuit with refrigerant with UV contrast agent, locate the leak in the circuit using the VAS 6201 leak detection kit and repair the leak.
10. If necessary, drain the refrigerant circuit.
11. Evacuate the refrigerant circuit and repeat the vacuum gauge check within a few hours. Only if the vacuum is maintained can you begin filling.