Possible deviation from specification | Possible cause of fault | Rectifying fault |
l
| High pressure increases only slightly above the pressure measured when the engine is stopped. |
l
| Low pressure falls only slightly. |
l
| The required cooling output is not delivered. |
| t
| Actuation of air conditioner compressor regulating valve -N280- is defective. |
| –
| Check actuation of air conditioner compressor regulating valve -N280-. |
|
| t
| The air conditioner compressor is defective. |
| –
| Rinse (clean) refrigerant circuit → Chapter. |
–
| Renew air conditioner compressor. |
–
| Recharge refrigerant circuit. |
|
l
| High pressure increases beyond the specification. |
l
| Low pressure falls quickly to the diagram value or lower. |
l
| The required cooling output is not delivered. |
| t
| Actuation of air conditioner compressor regulating valve -N280- is defective. |
| –
| Check actuation of air conditioner compressor regulating valve -N280-. |
|
| t
| Restriction or obstruction in the refrigerant circuit. |
| –
| Feel the refrigerant circuit with the hand to sense the temperature gradient. |
l
| At one component a temperature gradient will be detected: |
–
| If a hose or pipe is kinked or crushed, renew it. |
–
| In case of an obstruction, blow through refrigerant circuit with compressed air and nitrogen. |
–
| Recharge refrigerant circuit. |
l
| If no faults are found: |
–
| Rinse (clean) refrigerant circuit → Chapter. |
–
| Recharge refrigerant circuit. |
–
| Repeat the check; if the system does not operate correctly |
|
| t
| Expansion valve defective. |
| –
| Renew the expansion valve and receiver. |
–
| Recharge refrigerant circuit. |
|