Toro 02750 - Page 61

Issued: 01.04.11 Approved: Mod. No. 5060358 Sheet 61 of 64 Part No. 111-4431 (A)
ROPS CAB, AIR CONDITIONING AND HEATING INSTALLATION - MAINTENANCE Continued
General notes for refrigerant lling:
- Low levels of refrigerant can reduce the efciency of the air conditioning unit.
- Extremely low levels can cause the low pressure switch to shut down the system.
- As a check on refrigerant level, there is an integrated sight glass in the collecting tank. After lling, run the system
for 5 minutes to allow all air bubbles to be purged from the system. Check the level after this period and top up is
necessary. The occasional air bubble can be accepted.
Examination of refrigerant pressure:
- When using the air conditioning system the operating pressure is different on the suction side and the pressure side
of the compressor.
- This pressure difference is inuenced by the speed of the compressor, the inside temperature of the vehicle, the
outside air temperature and the relative air humidity.
- Pressures that differ from those in the table below indicate a possible fault in the system.
- To check the pressures, set the compressor speed to 2000 rev / min with an air temperature of between 20° and 40°
the blower should be operated at position 3 (fastest speed setting).
System refrigerant pressures:
Outside temperature Low pressure side High pressure side
20°C 1.9bar ± 0.2bar 12bar ± 2bar
25°C 2.0bar ± 0.2bar 14bar ± 2bar
30°C 2.1bar ± 0.2bar 16bar ± 2bar
- During the pressure test the results can indicate the nature of the fault.
- Pressure on high pressure side too high indicates:
A - Insufficient volume over the condenser
B - Refrigerant quantity too high
C - Dryer filter is blocked
- Pressure on high pressure side too low indicates:
A - Refrigerant level too low (check sight glass)
B - Compressor speed too low (check belt tension)
C - Fault with the compressor
- Pressure on low pressure side too high indicates:
A - Incorrect expansion valve
B - Compressor speed too low (check belt tension)
C - Fault with the compressor
- Pressure on low pressure side too low indicates:
A - Throttling in the suction or pressure pipe, e.g., by line breaks
B - Incorrect expansion valve
C - Refrigerant level too low (examine sediment bowl)
D - Insufficient air volume over evaporator