1. Personal Protective Equipment (PPE)
1.1. - Importance of PPE
1.2. - Must be worn at all times to avoid risk
2. Nitrogen Leak Test Procedures
2.1. Insufficient refrigerant charge must checked for leakes, repaired and recharged
2.2. Perform nitrogen leak test after repair and service process
2.3. Connect manifold gauge high pressure hose to suction valve and service hose to nitrogen
2.4. Pressurise the system according to manifacturer spec with dry nitrogen and close the valve when the gauge reading reach 20 bar. Perform leak test procedure by applying spray leak detector on RAC system connection
2.5. Release the remaining nitrogen to the atmosphere slowly. If has a leakage, do a repairing process
3. Choking and Pressure Test Procedures
3.1. Ensure no blocking due to improper blazing
3.2. Connection procedure
3.2.1. Connect manifold gauge to nitrogen cylinder. High pressure to suction valve
3.2.2. Use dry nitrogen to pressurise the system 2 bar at least 10 min. If no leak, increase pressure to 10 bar at least 10 min.
3.2.3. Place a piece of paper at the outlid of both connection to check nitrogen flow
4. Filter Drier Replacement Procedures
4.1. Carry out according to manifacturer spec
5. Cleaning and Flushing Procedures
5.1. Componen
5.1.1. Condenser
5.1.1.1. Connect with hose and nitrogen cylinder
5.1.1.2. Use dry nitrogen, pressure regulator 72-154 psi
5.1.1.3. Hexane or Methylene Dichloride (MDC) is compulsory. Make sure theres no liquid before completing prosedure
5.1.2. Evaporator
5.1.2.1. Connect with hose and nitrogen cylinder
5.1.2.2. Use dry nitrogen, pressure regulator 72-154 psi
5.1.2.3. Hexane or Methylene Dichloride (MDC) is compulsory. Make sure theres no liquid before completing prosedure
5.1.3. Nitrogen Cylinder
6. 10. Charging Refrigerant Procedures
6.1. To avoid undercharging and overcharging, refer manufacturer label
6.2. Tools
6.2.1. Refrigerant charging scale, 4 way manifold gauge and leak detector
6.3. Use pure refrigerant that meets AHRI standard 700 spec
6.4. Make sure AC off and ensure all hose is already vacuumed. Then set the amount of charge
6.5. Place tank on charging scale, measure the weight. Open vapour valve on recovery tank. Manifold gauge low valve to open. Close "HIGH" and "VAC" valve. Open "REF" and monitor refrigerant charging scale until meet specification
6.6. Close all valve and check for leakage by using leak detector
7. 12. Sealing Process Tube and Customer Awareness
7.1. Seal process tube
7.2. Perform leak test using spray leak detector before operating AC
8. Tools Inspection Procedures
8.1. - Perform tools inspection
8.1.1. Suitable manifold gauge
8.1.2. Check needle and calibrate
8.1.3. Manifold gauge is not broken
8.1.4. Hose seal rating condition
8.1.5. UseLeak detector to check leaking
8.1.6. Check vacuum pump, Micron Gauge, Refregerant charging scale, Clamp on ammeter, Thermometer, Safety valve
8.1.7. Recovery tank
8.1.7.1. Purge tank if contaminated
8.1.7.2. Avoid mixed contamination
9. Run and Inspection Test rocedure
9.1. Type K thermocouple
9.2. 4 way manifold gauge
9.3. Clamp on ammeter
9.4. Safety valve
10. Recovery Procedures
10.1. Ensure AC is off before recovery
10.2. Tools
10.2.1. 4 way manifold gauge
10.2.2. Micron gauge
10.2.3. Vacuum pump
10.2.4. Filter dryer
10.2.5. Recovery machine
10.2.6. Recovery tank
10.2.7. Refrigerant charging scale
10.2.8. Safety valve
10.3. Record recovery tank weight and connect recovery machine to power supply.
10.4. Switch on recovery machine and wait until pressure gauge reach 0 psig.
10.5. Close all manifold gauge valve, inlet valve recovery machine and turn to "PURGE" function.
10.6. Press start until inlet reach 0 psig
10.7. Record the quantity of recovered refrigerant and then close all valve
11. 9. Vacuum Procedures
11.1. Vacuum 500 micron or lower. Vacuum can perform 20-50 micron and micron gauge that can read 5-5000 micron.
11.2. All manifold gauge valve is closed. Connect low side hose to suction valve with safety valve. connect micron gauge to manifold gauge and vaccum hose to vacuum pump. Ref hose to vapour valve on refrigerant cylinder
11.3. Swtich on micron gauge, vacuum pump and shut off valve, open VAC valve. open low valve and safety valve
11.4. Open REF valve and wait until micron gauge reach 500 micron
11.5. Close shut off valve and switch off for 10 min and monitor micron gauge reading. If its increase to 1500 micron, it indicate leakage. If no leakage, close all valve and proceed to charging
12. 11. Performance Test – After Service Procedures
12.1. Switch on AC to do performance test after service or repair
12.2. Tools
12.2.1. K thermocouple, 4 way manifold gauge, clamp on ammeter and safety valve
12.3. After switch on, wait for 15-30 min. Dont block the return and supply air temperature measure.
12.4. Use type K thermocouple to measure temperature at return and supply indoor unit. Different of temperature must be 8-12 degree centigrade. If the difference is not achieved, futher troubleshooting is needed
12.5. Low pressure :- connect 4 way manifold gauge to the safety valve and safety valve to condenser unit in fully closed position. Open the safety valve and record the pressure reading.
12.5.1. Running Amp: using clamp ampmeter around live cable at condenser unit refer to manufacturer label