SEAT Workshop Service and Repair Manuals

Specifications: High-pressure side: Increasing by a maximum of 20 bar from the initial pressure (when connecting the manometers). Low-pressure side:

Decreasing to the value of the diagram from the initial pressure (when connecting the manometers). A -  High pressure (measured at the service connection) in bar positive pressure. B -  Low pressure (measured at the valve connection of the compressor or the collecting tank) in bar. C -  Permitted tolerance range. D -  Low pressure (measured at the connection with the valve for the low-pressure switch or at the service connection) in bar positive pressure. E -  Permitted tolerance range.

Possible deviation from specification	Possible cause of fault	How to rectify fault
l  High pressure remains constant or increases only slightly (above the pressure measured when the engine is stopped), l  The low pressure falls to the diagram value or lower, l  Required cooling output is not attained	Insufficient refrigerant in circuit.	–  Find leak with leak detector and eliminate. –  Recharge refrigerant circuit.
l  High pressure is normal, l  Low pressure matches the diagram value, l  Required cooling output is not attained
l  High pressure is normal, l  Low pressure too low (see graph) l  Required cooling output is not attained

Clean the refrigerant circuit (rinse with refrigerant R134a or sweep with compressed air or nitrogen).

Possible deviation from specification	Possible cause of fault	Measures to be taken
l  High pressure increases only slightly above the pressure measured when the engine is stopped, l  Low pressure falls only slightly, l  Required cooling output is not attained	Compressor defective	–  Clean refrigerant circuit (flush with refrigerant R134a or blow out with compressed air and nitrogen ). –  Renew compressor.

Possible deviation from specification	Possible cause of fault	How to rectify fault
l  High pressure rises above specification, l  The low pressure falls to the diagram value or lower, l  Required cooling output is not attained	Restriction or obstruction in the refrigerant circuit.	–  Feel AC circuit with hand to determine temperature differences. l  If temperature differences are perceptible on a component: –  Renew hose or pipe if kinked or constricted. –  In the event of clogging of the refrigerant circuit, clean (flush with refrigerant R134a or blow out with compressed air and nitrogen ). l  If no fault is found. –  Clean refrigerant circuit (flush with refrigerant R134a or blow out with compressed air and nitrogen ).
l  High and low pressure normal at first l  The high pressure increases beyond the specified value, l  The low pressure falls to the diagram value or lower, l  Required cooling output is not attained	Moisture in the refrigerant circuit.	–  Blow through refrigerant circuit with compressed air and nitrogen. –  Replace the collecting tank. –  Repeat the check. If operation is not correct: –  Flush the refrigerant circuit (clean) –  Recharge refrigerant circuit. –  Repeat check.
l  High and low pressure normal at first l  After lengthy operating period, low pressure drops excessively (evaporator ices up)	The air conditioner compressor is defective.	–  Flush the refrigerant circuit (clean) –  Renew the air conditioner compressor.

t	In the case of the fault „High pressure normal, low pressure too low“, the following must be taken into account:

t	If this fault occurs, the evaporator may be frozen, or the air-conditioner low-pressure switch -F73- may disconnect the compressor in spite of the fact there is a correct amount of refrigerant in the circuit.

Possible deviation from specification	Possible cause of fault	Measures to be taken
l  High pressure normal or too high. l  Low pressure too low (see graph) l  the air-conditioner compressor is noisy (especially after connection), l  Required cooling output is not attained	Too much refrigerant in circuit	–  Extract some refrigerant from the refrigerant circuit. l  The quantity of refrigerant extracted is about equal to the prescribed charge quantity. –  Renew the air conditioner compressor. l  The quantity of refrigerant extracted is significantly greater than the prescribed charge quantity. –  Recharge refrigerant circuit. –  Repeat check.

Possible deviation from specification	Possible cause of fault	Measures to be taken
l  High and low pressure normal l  Required cooling output is not attained	Too much refrigerant oil in the circuit.	–  Drain refrigerant circuit. –  Clean refrigerant circuit (flush with refrigerant R134a or blow out with compressed air and nitrogen ).
l  High and low pressure normal l  Compressor noise (particularly after switch-on) l  Required cooling output is attained

t	Overfilling with refrigerant oil can occur if the refrigerant oil level was not checked after the air conditioner compressor was renewed.

t

If the air conditioner compressor is not replaced, the refrigerant must be extracted from the compressor (replace the O-ring) via the oil drain plug. Fill the 50 grams in the → Repair Manual of the respective vehicle indicated complete refrigerant oil quantity in the air conditioner compressor and the rest in the refrigerant circuit.