Refrigerant Shut-Off Valves
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NOTE:
Different versions of the shut-off valve are available with different functions and with different names. For example, the Hybrid Battery Refrigerant Shut-Off Valve 1 -N516- illustrated in the following is installed on an Audi Q5 hybrid. Refer to Refrigerant Circuit (vehicle-specific Service Information).
There are various designations, depending on the function and the vehicle. Refer to Refrigerant Circuit (vehicle-specific Service Information).
Shut-Off Valves with Two States of Operation (Open or Closed)
- Hybrid Battery Refrigerant Shut-Off Valve 1 -N516- (for example on the Audi Q5 Hybrid)
- Heater and A/C Unit Refrigerant Shut-Off Valve -N541- (for example on Audi A3 e-tron)
- High-Voltage Battery Heater Core Refrigerant Shut-Off Valve -N542- (for example on Audi A3 e-tron)
- Refrigerant Shut-Off Valve -V424- (for example on Audi Q7 e-tron)
- If the shut-off valve -A- is not activated by the electronics, it is open and lets the refrigerant flow through to the evaporator in the A/C unit.
- For example, the shut-off valve -A- is installed on vehicles with the battery cooling module. It is activated in hybrid mode when no A/C system operation is desired for the passenger compartment, but battery cooling is necessary for the Hybrid Battery Unit -AX1-.
- Pay attention to the arrow -B- on the shut-off valve -A-, which shows the flow direction of the refrigerant (from the condenser to the evaporator in the A/C unit)
- The solenoid coil -C- attached to the shut-off valve is activated, for example, by the Battery Regulation Control Module -J840-. Refer to Wiring Diagram and Vehicle Diagnostic Tester in the Guided Fault Finding Function for the A/C System and the Battery Regulation.
- For example, on a vehicle with two evaporators (one in the A/C unit and one in the battery cooling module, such as on the Audi Q5 Hybrid), if the measured temperature on one of the evaporators corresponds to the specified value or the specified value falls short, but the required specified value on the other evaporator is not reached, the following adjustment is performed: the relevant control module (for example, the Battery Regulation Control Module -J840- on the Audi Q5 hybrid) activates the electric A/C compressor with increased speed (thereby increasing the A/C system cooling output and decreasing the pressure on the low pressure side as well as the evaporator temperature) via the A/C Compressor Control Module -J842-. If the specified temperature value falls short at an evaporator, the relevant control module (for example, the Battery Regulation Control Module Battery Regulation Control Module -J840- on the Audi Q5 hybrid) activates the Hybrid Battery Refrigerant Shut-Off Valve 1 -N516- or the Hybrid Battery Refrigerant Shut-Off Valve 2 -N517-, so that the evaporator that is too cold is no longer supplied with refrigerant. Refer to Vehicle Diagnostic Tester in the Guided Fault Finding Function for the A/C System and Refrigerant Circuit (vehicle-specific Service Information).
Shut-Off Valves Regulated by Characteristic Curves
- Refrigerant Shut-Off Valve 2 -N640- through Refrigerant Shut-Off Valve 5 -N643- (for example on Audi Q7 e-tron)
- Refrigerant Expansion Valve 1 -N636- (for example on Audi Q7 e-tron)
- The shut-off valve -A- is activated via a stepper motor -B- by the respective control module using the characteristic curves (opened or closed).
- If the shut-off valve works as a regulator valve (for example, on the Audi Q7 as Refrigerant Expansion Valve 1 -N636-), it is opened just enough so that the temperature for the heater core is reached. Refer to Refrigerant Circuit (vehicle-specific Service Information.
- Shut-off valves activated by stepper motors do not have a specified resting position. Therefore they must be set to a certain position (open or closed) before performing work on the refrigerant circuit. Refer to Refrigerant Circuit (vehicle-specific Service Information).
- Depending on the refrigerant circuit design, multiple shut-off valves may be combined in a valve block (for example, on the Audi Q7 e-tron). Refer to Refrigerant Circuit (vehicle-specific Service Information).
- The stepper motor is adapted and activated via the data wires (LIN bus) by the respective control module according to its component location. Use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function and refer to Refrigerant Circuit (vehicle-specific Service Information).