seat Workshop Repair Guides

SEAT Workshop Service and Repair Manuals

ABOUT US
Checking with expansion valve, receiver and A/C compressor regulating valve, air conditioning system N280 (with externally reg > < Checking with restrictor, reservoir and A/C compressor regulating valve, air conditioning system N280 (with externally regulat

Leon Mk2

Specifications:
Specifications:
High-pressure side:
Rising from starting pressure (when manometer is connected) to 20 bar.
Low-pressure side:
   
Falling from starting pressure (when manometer is connected) to diagram value.
A - Low pressure (measured at the service connection) in bar absolute pressure.
B - Control current for A/C compressor regulating valve, air conditioning system -N280-.
C - Permitted tolerance range.
  Note!
t  Under unfavourable conditions (very high ambient temperatures, high atmospheric humidity), the pressure on the high-pressure side can increase to a maximum of 29 bar.
t  The control current -B- is indicated in the measured values block.
t  The high pressure is indicated in the measured values block → Rep. Gr.87.
t  The low pressure is adjusted to within tolerances within the output range for the air conditioner compressor depending on the control current for the A/C compressor regulating valve, air conditioning system -N280-.
t  Under unfavourable conditions (very high ambient temperatures, high atmospheric humidity), the output may be insufficient to achieve the specification in every case.
t  The specified working current for the regulating valve must be greater than 0.3 A to ensure that the regulating valve is reliably activated.
t  At the setting for “maximum cooling power”, the control current should be approx. 0.8 A (indicated in the measured values block) → Rep. Gr.87.
t  Absolute pressure means that 0 bar corresponds to an absolute vacuum. The normal ambient pressure corresponds to 1 bar absolute pressure. On most manometers, a reading of 0 bar corresponds to an absolute pressure of one bar (which is confirmed by the existence of a -1 bar marking beneath the 0 scale marking).
  A87-0377
Possible deviation from specification Possible cause of faultRectifying fault
l  High pressure remains constant or increases only slightly (above the pressure measured when the engine is stopped),
l  Low pressure falls quickly to the diagram value or lower,
l  the required cooling power is not delivered.
t  Actuation of A/C compressor regulating valve, air conditioning system -N280- defective.
t  Insufficient refrigerant in circuit.
–  Check actuation of A/C compressor regulating valve, air conditioning system -N280-.
–  Look for leaks using leak detector and rectify them.
–  Recharge refrigerant circuit.
l  High pressure normal,
l  Low pressure matches the diagram value,
l  the required cooling power is not delivered.
  
l  High pressure normal,
l  Low pressure is too low (see diagram),
l  the required cooling power is not delivered.
l  High pressure normal,
l  Low pressure is too low (see diagram),
l  the required cooling power is not delivered.
  

  Note!
If no fault can be found for this complaint, flush refrigerant circuit with compressed air and nitrogen.
   
Possible deviation from specificationPossible cause of faultRectifying 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 power is not delivered.
t  Actuation of A/C compressor regulating valve, air conditioning system -N280- defective.
t  A/C compressor defective.
–  Check actuation of A/C compressor regulating valve, air conditioning system -N280-.
–  Rinse (clean) refrigerant circuit → Chapter.
–  Renew air conditioner compressor.
l  High pressure increases beyond the specification,
l  Low pressure falls only slightly,
l  the required cooling power is not delivered.
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, flush refrigerant circuit with compressed air and nitrogen.
l  If no faults are found:
–  Rinse (clean) refrigerant circuit → Chapter.
l  High pressure and low pressure are normal at first, but after a while, the high pressure increases beyond the specification,
l  the low pressure falls to the diagram value or lower,
l  the cooling power called for is not delivered.
t  Moisture in the refrigerant circuit.
–  Flush refrigerant circuit with compressed air and nitrogen.
–  Renew reservoir.
–  Repeat the check; if the system does not operate correctly
–  Rinse (clean) refrigerant circuit → Chapter.
–  Recharge refrigerant circuit.
–  Repeat check.
l  High pressure normal,
l  Low pressure is too low (see diagram),
l  the cooling power called for is delivered.
t  Actuation of A/C compressor regulating valve, air conditioning system -N280- defective.
t  A/C compressor defective.
–  Check actuation of A/C compressor regulating valve, air conditioning system -N280-.
–  Rinse (clean) refrigerant circuit → Chapter.
–  Renew air conditioner compressor.

  Note!
t  If the fault is “high pressure normal, low pressure too low ” note the following: defective, the evaporator can ice up or the required cooling power is not delivered.
t  In this case, the evaporator may ice up although the correct quantity of refrigerant is present in the refrigerant circuit.
t  Check the measured value of the evaporator output temperature sender -G263-.
t  Check actuation of A/C compressor regulating valve, air conditioning system -N280-
→ Rep. Gr.87
   
Possible deviation from specification Possible cause of faultRectifying fault
l  High pressure normal or too high,
l  Low pressure too high (see diagram),
l  The air conditioner compressor is noisy (especially immediately after being switched on),
l  the required cooling power is not delivered.
t  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 conditioning system compressor.
l  The quantity of refrigerant extracted is significantly greater than the prescribed charge quantity:
–  Recharge refrigerant circuit.
–  Repeat check.
l  High pressure and low pressure are normal,
l  the required cooling power is not delivered.
t  Too much refrigerant in the circuit.
–  Evacuate refrigerant circuit.
–  Rinse (clean) refrigerant circuit → Chapter.
l  High pressure and low pressure are normal,
l  The air conditioner compressor is noisy (especially immediately after being switched on),
l  the cooling power called for is delivered.
  

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

Checking with expansion valve, receiver and A/C compressor regulating valve, air conditioning system N280 (with externally reg > < Checking with restrictor, reservoir and A/C compressor regulating valve, air conditioning system N280 (with externally regulat