Refrigerant Capacity

REFRIGERANT CAPACITY TEST:

NOTES:
- For tests in workshop, in the event of complaints due to insufficient cooling capacity and for trouble diagnosis on air conditioning systems, proceed according to the following test method, which is applicable for ambient temperatures from +20°C to +40°C.
- All check values can be read after 10 minutes of constant operation. The values named are max. values and should not be exceeded.
- The vehicle should not be exposed to sunshine before and during test.

TEST PROCEDURE:
1. Test tension of V-belt for compressor drive.

Sight Glass On Receiver Dehydrator:

2. Push function selection button "c" and run engine at idle. On sight glass (arrow) in receiver dehydrator, check whether coolant flows through free of bubbles shortly after switching on electromagnetic clutch If refrigerant charge is insufficient, fill up system. If refrigerant loss exceeds 200 g, check system for leaks.

Lever For Center Nozzle:

3. Open lever (arrow) for center nozzles as well as levers for lateral nozzles left and right.
4. Attach a thermometer for outside air temperature (ambient temperature) approx. 2 meters from driver's side.
5. Place a hygrometer into storage tray of center console.
6. Connect suction and pressure gauge to service valves.
7. Plug one thermometer each into center nozzle and lefthand side nozzle.
8. Open window, close vehicle doors and engine hood.

ACC Pushbutton Control Unit:

9. Temperature dial engaged in "MIN" position. Push blower switch (f) 6th stage.
10. Run engine at approx. 2000/min.

Table:

Image Reference:
1): Relative humidity
Ta: Outside temperature (°C)
A: Air outlet temperature (°C)
B: Pressure before compressor (bar)
C: Pressure after compressor (bar)
D: Coolant temperature (°C)

11. After approx. 10 minutes of operating time, read values on thermometers and pressure gauges, as well as on hygrometer and compare with values of table.

NOTE: Specified data are max. data and should not be exceeded.

ETR Switch (29):

12. Check cutout temperature of Evaporator Temperature Regulator (ETR) switch (29) by plugging 1 thermometer into center nozzle. Push blower switch (h) 1st stage and pushbutton (c) in control unit and run engine at approx. 2000/min. After 3rd cutout of electromagnetic clutch, the outlet temperature should amount to approx. +4°C, but should not be < +3°C.

NOTE: If cooling capacity is insufficient or outlet temperatures are below +3°C, check capillary of ETR switch (29) for correct assembly (slipped in up to marking between ribs of evaporator) or replace ETR switch.