Checking System Tightness

Checking System Tightness (Vacuum Pumping) With RHS 650
The following must be observed when performing the tightness check. Firstly, the national regulations in the particular country must be followed. Secondly, the following procedure must be followed:
- Check compressor oil level and top up as required before vacuum-pumping A/C system.
Servicing System

- The main purpose of vacuum-pumping is to evacuate any moisture present in the system. The second purpose is to ensure that no leakage is present. When vacuum-pumping has been completed and the system is completely tight, fill the system with the correct quantity and type of refrigerant.
Specifications

- Vacuum-pump system for approx. 50 minutes. Procedure commences with operation one.

- Carry out a final check using leak detector 9511207.

1. Connect:
- low-pressure hose (blue) between high-pressure circuit (14) of unit and A/C system in car
- high-pressure hose (red) to low-pressure circuit of unit.
2. Open:
- valves (2) and (3)
- check that service valve connected to A/C system of car is open.
3. Close:
- connection (20) i.e. turned counterclockwise to end position
- valves (1) and (4)
- main switch.
4. Set selector switch (7) to EVACUATION to start vacuum pump.
Allow vacuum-pumping to proceed for at least 50 minutes, by which time vacuum gauge (6) will indicate pressure of 0.7-1.0 bar (10.2-14.5 psi). Vacuum-pumping must continue for at least 50 minutes to ensure that all moisture is extracted.





5. Carry out tightness check.
- valve (1) should be closed
- valve (2) should be open
- close valve (3)
- valve (4) should be closed.
6. Read vacuum gauge (6).
- Vacuum must not fall by more than 0.1 bar (1.45 psi) (towards atmospheric) within 4 minutes.
- If pressure rises above 0 bar within 4 minutes, moisture or leakage is present in A/C system.
- Check system for leakage if vacuum gauge reading rises (i.e vacuum falls) by more than 0.1 bar within 4 minutes.
7. Switch off unit by opening main switch (11).