Volkswagen Tiguan Service and Repair Manual: Refrigerant Circuit Components

Refrigerant Circuit Component Arrangement

Caution

Non-approved tools or materials such as leak sealing additives can cause damage or malfunctions in the system.

Only use tools and materials approved by the manufacturer.

The warranty is voided if non-approved tools or materials are used.

• All components of the refrigerant circuit submitted for quality observation are always to be sealed (use original sealing caps of original part).
• Replace damaged or leaking components of refrigerant circuit.
• To date, the original parts (compressor, reservoir, receiver/dryer, evaporator and condenser) have been filled with nitrogen gas. This charge is being gradually discontinued. There is little or no pressure equalization when removing the sealing plugs from the original part.

High pressure side are the condenser, receiver/dryer and restrictor or expansion valve to separate the high and low pressure liquid ends.

High pressure results from the restrictor or expansion valve forming a constriction and causing the refrigerant to accumulate, thus leading to an increase in pressure and temperature.

Excess pressure results if too much refrigerant or refrigerant oil is used, the condenser is contaminated, the coolant fan is malfunctioning, the system is blocked or if there is moisture in the refrigerant circuit (the restrictor or expansion valve freezes).

Low pressure side are the evaporator, reservoir, evaporator temperature sensor and compressor to separate high and low pressure gas ends.

A drop in system pressure can occur due to loss of refrigerant, restrictor or expansion valve (restriction not given), A/C compressor malfunction or iced evaporator.

A/C Compressor with A/C clutch:

Caution

Non-approved tools or materials such as leak sealing additives can cause damage or malfunctions in the system.

Only use tools and materials approved by the manufacturer.

The warranty is voided if non-approved tools or materials are used.

• All components of the refrigerant circuit submitted for quality observation are always to be sealed (use original sealing caps of original part).
• Replace damaged or leaking components of refrigerant circuit.
• To date, the original parts (compressor, reservoir, receiver/dryer, evaporator and condenser) have been filled with nitrogen gas. This charge is being gradually discontinued. There is little or no pressure equalization when removing the sealing plugs from the original part.

The engine drives the A/C compressor via a ribbed belt.

An electromagnetic clutch installed on the A/C compressor creates a frictional connection between the ribbed belt pulley and A/C compressor crankshaft when the air conditioning system is switched on.

If the A/C compressor sticks, a fuse installed in the compressor ribbed belt pulley releases the electromagnetic clutch and protects the ribbed belt pulley from overload.

The A/C compressor extracts the refrigerant gas from the evaporator, compresses it and relays it to the condenser.

Note

• The A/C compressor contains refrigerant oil, which can be mixed with refrigerant R134a under any temperature.
• The type plate lists the type of refrigerant required for the A/C compressor. A regulator valve regulates pressure within the specified range (control characteristics) on the low pressure side.
• So that the A/C compressor does not get damaged when the refrigerant circuit is empty, the A/C clutch is turned off and the A/C Compressor Regulator Valve -N280- is no longer activated (A/C compressor runs at idle with engine).

A/C Compressor without Magnetic Clutch

Caution

Non-approved tools or materials such as leak sealing additives can cause damage or malfunctions in the system.

Only use tools and materials approved by the manufacturer.

The warranty is voided if non-approved tools or materials are used.

• All components of the refrigerant circuit submitted for quality observation are always to be sealed (use original sealing caps of original part).
• Replace damaged or leaking components of refrigerant circuit.
• To date, the original parts (compressor, reservoir, receiver/dryer, evaporator and condenser) have been filled with nitrogen gas. This charge is being gradually discontinued. There is little or no pressure equalization when removing the sealing plugs from the original part.

The engine drives the A/C compressor via a ribbed belt.

Overload protection (shear) installed in the A/C compressor ribbed belt pulley releases when the compressor stops and protects the ribbed belt pulley from being overloaded.

The A/C compressor extracts the refrigerant gas from the evaporator, compresses it and relays it to the condenser.

Note

• The A/C compressor contains refrigerant oil, which can be mixed with refrigerant R134a under any temperature.
• The type plate lists the type of refrigerant required for the A/C compressor. A regulator valve regulates pressure within the specified range (control characteristics) on the low pressure side.
• On this A/C compressor, the control valve is activated from outside.
• The engine should only be started if the refrigerant circuit is completely assembled.
• The A/C compressor is equipped with a protected oil supply, this prevents A/C compressor damage in the event that the system is empty. This means that approximately 40 to 50 cm³ of refrigerant oil remains in the A/C compressor.

A/C without Magnetic Clutch with Torsion-Elastic Clutch

Caution

Non-approved tools or materials such as leak sealing additives can cause damage or malfunctions in the system.

Only use tools and materials approved by the manufacturer.

The warranty is voided if non-approved tools or materials are used.

• All components of the refrigerant circuit submitted for quality observation are always to be sealed (use original sealing caps of original part).
• Replace damaged or leaking components of refrigerant circuit.
• To date, the original parts (compressor, reservoir, receiver/dryer, evaporator and condenser) have been filled with nitrogen gas. This charge is being gradually discontinued. There is little or no pressure equalization when removing the sealing plugs from the original part.

The A/C compressor is driven directly by the power steering vane pump.

On the A/C compressor driveshaft, there is an overload protection that shears off when the compressor is blocked so that the power steering vane pump remains functional.

The A/C compressor extracts the refrigerant gas from the evaporator, compresses it and relays it to the condenser.

Note

• The A/C compressor contains refrigerant oil, which can be mixed with refrigerant R134a under any temperature.
• The type plate lists the type of refrigerant required for the A/C compressor. A regulator valve regulates pressure within the specified range (control characteristics) on the low pressure side.
• On this A/C compressor, the control valve is activated from outside.
• The engine should only be started if the refrigerant circuit is completely assembled.
• The A/C compressor is equipped with a protected oil supply, this prevents A/C compressor damage in the event that the system is empty. This means that approximately 40 to 50 cm³ of refrigerant oil remains in the A/C compressor.

Electrically-Driven A/C Compressor for High Voltage System

Caution

Non-approved tools or materials such as leak sealing additives can cause damage or malfunctions in the system.

Only use tools and materials approved by the manufacturer.

The warranty is voided if non-approved tools or materials are used.

• All components of the refrigerant circuit submitted for quality observation are always to be sealed (use original sealing caps of original part).
• Replace damaged or leaking components of refrigerant circuit.
• To date, the original parts (compressor, reservoir, receiver/dryer, evaporator and condenser) have been filled with nitrogen gas. This charge is being gradually discontinued. There is little or no pressure equalization when removing the sealing plugs from the original part.

WARNING

• Hybrid vehicles have a high voltage system. Health risks to persons with life assist systems.
• It will also be necessary to work on the high voltage system when performing the following procedures. Any work to be performed on a vehicle with a high voltage electrical system may only be performed by technician specifically trained to work on this system. The work must be performed by a certified high voltage technician.
• Follow the General Warnings for working on the high voltage electrical system ⇒ Electric Drive; Repair Group 93; General Warnings for Working on High Voltage Electrical Systems.
• De-energize the high voltage system. Refer to Electric Drive; Repair Group 93; High Voltage System, De-Energizing.

WARNING

The electrically-driven A/C compressor has a different refrigerant oil!

See vehicle-specific repair manual.

Electrically-driven A/C compressor

WARNING

Danger of short circuit

The A/C compressor works with 288 volts at 800 to 8,600 RPM.

Do not touch the A/C compressor when starting the drive generators, danger of short circuit.

The A/C compressor extracts the refrigerant gas from the evaporator, compresses it and relays it to the condenser.

Note

• The A/C compressor contains refrigerant oil, which can be mixed with refrigerant R134a under any temperature.
• The type plate lists the type of refrigerant required for the A/C compressor. The RPM controls the delivery.
• The engine should only be started if the refrigerant circuit is completely assembled.
• The A/C compressor is equipped with a protected oil supply, this prevents A/C compressor damage in the event that the system is empty. This means that approximately 40 to 50 cm³ of refrigerant oil remains in the A/C compressor.
• The A/C compressor has a relief valve.

Condenser

Caution

Non-approved tools or materials such as leak sealing additives can cause damage or malfunctions in the system.

Only use tools and materials approved by the manufacturer.

The warranty is voided if non-approved tools or materials are used.

• All components of the refrigerant circuit submitted for quality observation are always to be sealed (use original sealing caps of original part).
• Replace damaged or leaking components of refrigerant circuit.
• To date, the original parts (compressor, reservoir, receiver/dryer, evaporator and condenser) have been filled with nitrogen gas. This charge is being gradually discontinued. There is little or no pressure equalization when removing the sealing plugs from the original part.

The condenser conducts heat from compressed refrigerant gas to the ambient air.

This condenses the refrigerant gas to fluid.

Evaporator

Caution

Non-approved tools or materials such as leak sealing additives can cause damage or malfunctions in the system.

Only use tools and materials approved by the manufacturer.

The warranty is voided if non-approved tools or materials are used.

• All components of the refrigerant circuit submitted for quality observation are always to be sealed (use original sealing caps of original part).
• Replace damaged or leaking components of refrigerant circuit.
• To date, the original parts (compressor, reservoir, receiver/dryer, evaporator and condenser) have been filled with nitrogen gas. This charge is being gradually discontinued. There is little or no pressure equalization when removing the sealing plugs from the original part.

The fluid refrigerant evaporates in the evaporator pipe coils. The heat required for this is extracted from the air flowing on the evaporator ribbing. The air cools off. Refrigerant evaporates and is extracted with the absorbed heat by the A/C compressor.

A defined amount of refrigerant is supplied to the evaporator by a restrictor or expansion valve. In systems with expansion valve, the throughput is regulated so that only gaseous refrigerant escapes the evaporator outlet.

Reservoir

Caution

Non-approved tools or materials such as leak sealing additives can cause damage or malfunctions in the system.

Only use tools and materials approved by the manufacturer.

The warranty is voided if non-approved tools or materials are used.

• All components of the refrigerant circuit submitted for quality observation are always to be sealed (use original sealing caps of original part).
• Replace damaged or leaking components of refrigerant circuit.
• To date, the original parts (compressor, reservoir, receiver/dryer, evaporator and condenser) have been filled with nitrogen gas. This charge is being gradually discontinued. There is little or no pressure equalization when removing the sealing plugs from the original part.

The reservoir collects the vaporized and gaseous mixture coming from the evaporator to ensure the compressor only receives gaseous refrigerant. Gaseous refrigerant is formed from the vapor.

The refrigerant oil flowing in the circuit is not retained in the reservoir as it has an oil drilling.

Moisture which has entered the refrigerant circuit during repairs will be collected by a filter (desiccant bag) in the reservoir.

Gaseous refrigerant is extracted with oil by the A/C compressor.

Note

• Replace the reservoir if refrigerant circuit has been open for a long time (beyond the normal repair time) and moisture has penetrated inside, or if required due to a specific complaint.
• Remove sealing plugs -A- and -B- only immediately prior to installing.
• A desiccant bag in an unsealed reservoir is saturated with moisture after a short period of time and unusable.
• When installing, note arrow for direction of flow if necessary.

Restrictor

Caution

Non-approved tools or materials such as leak sealing additives can cause damage or malfunctions in the system.

Only use tools and materials approved by the manufacturer.

The warranty is voided if non-approved tools or materials are used.

• All components of the refrigerant circuit submitted for quality observation are always to be sealed (use original sealing caps of original part).
• Replace damaged or leaking components of refrigerant circuit.
• To date, the original parts (compressor, reservoir, receiver/dryer, evaporator and condenser) have been filled with nitrogen gas. This charge is being gradually discontinued. There is little or no pressure equalization when removing the sealing plugs from the original part.

The restrictor creates a constriction. This restriction reduces the flow and creates high and low pressure sides in the refrigerant circuit. Before the restrictor the refrigerant which is under a higher pressure is warm. After the restrictor the refrigerant which is under a low pressure is cold. Before the restriction there is a strainer for contaminants and after the restriction there is a strainer, to atomize the refrigerant before it reaches the evaporator.

Note

• Arrow -A- on restrictor points to evaporator.
• Replace after each opening of the circuit.
• Note different versions.

Receiver/Dryer

Caution

Non-approved tools or materials such as leak sealing additives can cause damage or malfunctions in the system.

Only use tools and materials approved by the manufacturer.

The warranty is voided if non-approved tools or materials are used.

• All components of the refrigerant circuit submitted for quality observation are always to be sealed (use original sealing caps of original part).
• Replace damaged or leaking components of refrigerant circuit.
• To date, the original parts (compressor, reservoir, receiver/dryer, evaporator and condenser) have been filled with nitrogen gas. This charge is being gradually discontinued. There is little or no pressure equalization when removing the sealing plugs from the original part.

The receiver/dryer collects the fluid drops and then directs them in an uninterrupted stream to the expansion valve. Moisture which has entered the refrigerant circuit during repairs will be collected by the dryer bag in the receiver/dryer.

Note

• Replace the receiver/dryer if refrigerant circuit has been open for a long time (beyond the normal repair time) and moisture has penetrated inside, or if required due to a specific complaint.
• Only remove sealing plugs shortly before installation.
• A dryer bag in an unsealed receiver/dryer is saturated with moisture after a short period of time and unusable.
• When installing, note arrow for direction of flow if necessary.

The new generation of receivers/dryers are installed directly on the condenser and contain a dryer cartridge.

Note

• Replace the dryer cartridge if refrigerant circuit has been open for a long time (beyond the normal repair time) and moisture has penetrated inside, or if required due to a specific complaint.
• Remove dryer cartridge from packaging shortly before installation.
• The dryer cartridge becomes saturated with moisture and unusable after a short time in an unsealed package.

Expansion Valve

Caution

Non-approved tools or materials such as leak sealing additives can cause damage or malfunctions in the system.

Only use tools and materials approved by the manufacturer.

The warranty is voided if non-approved tools or materials are used.

• All components of the refrigerant circuit submitted for quality observation are always to be sealed (use original sealing caps of original part).
• Replace damaged or leaking components of refrigerant circuit.
• To date, the original parts (compressor, reservoir, receiver/dryer, evaporator and condenser) have been filled with nitrogen gas. This charge is being gradually discontinued. There is little or no pressure equalization when removing the sealing plugs from the original part.

The expansion valve atomizes the streaming refrigerant and controls the flow quantity so that the vapor is gaseous only at the evaporator outlet, depending on the heat transmission.

O-Ring

Caution

Non-approved tools or materials such as leak sealing additives can cause damage or malfunctions in the system.

Only use tools and materials approved by the manufacturer.

The warranty is voided if non-approved tools or materials are used.

• All components of the refrigerant circuit submitted for quality observation are always to be sealed (use original sealing caps of original part).
• Replace damaged or leaking components of refrigerant circuit.
• To date, the original parts (compressor, reservoir, receiver/dryer, evaporator and condenser) have been filled with nitrogen gas. This charge is being gradually discontinued. There is little or no pressure equalization when removing the sealing plugs from the original part.

These o-rings seal off the connection points between individual components of the refrigerant circuit.

Only O-rings that are resistant to refrigerant r134a and refrigerant oil must be installed. Make sure they are original replacement parts.

O-ring:

• Always use only once.
• Make sure diameters -a- and -b- are correct.
• Coat with refrigerant oil before installing

Note

The color coding of refrigerant circuit o-rings with R134a has been discontinued. Colored and black O-rings are used.

Refer to the Parts Catalog.

Refrigerant Circuit Pipes and Hoses

Caution

Non-approved tools or materials such as leak sealing additives can cause damage or malfunctions in the system.

Only use tools and materials approved by the manufacturer.

The warranty is voided if non-approved tools or materials are used.

• All components of the refrigerant circuit submitted for quality observation are always to be sealed (use original sealing caps of original part).
• Replace damaged or leaking components of refrigerant circuit.
• To date, the original parts (compressor, reservoir, receiver/dryer, evaporator and condenser) have been filled with nitrogen gas. This charge is being gradually discontinued. There is little or no pressure equalization when removing the sealing plugs from the original part.

The mixture of refrigerant oil and refrigerant r134a corrodes certain metals (e.g. copper) and alloys and dissolves some hose materials. Therefore use original replacement parts only.

Pipes and hoses are joined by threaded connections or special plug connectors.

Note

Observe specified torque for threaded connections, use appropriate release tools for plug connectors.

Pressure Relief Valve

Caution

Non-approved tools or materials such as leak sealing additives can cause damage or malfunctions in the system.

Only use tools and materials approved by the manufacturer.

The warranty is voided if non-approved tools or materials are used.

• All components of the refrigerant circuit submitted for quality observation are always to be sealed (use original sealing caps of original part).
• Replace damaged or leaking components of refrigerant circuit.
• To date, the original parts (compressor, reservoir, receiver/dryer, evaporator and condenser) have been filled with nitrogen gas. This charge is being gradually discontinued. There is little or no pressure equalization when removing the sealing plugs from the original part.

The pressure relief valve is installed on the A/C compressor or receiver/dryer.

At a pressure of approximately 38 bar (551 psi) positive pressure, valve opens and closes again once pressure has dissipated (approximately 30 bar (435 psi) ).

Refrigerant does not escape completely.

Depending on the version, a transparent plastic disc may be installed which breaks off as soon as the valve is activated.

Refrigerant Circuit Design

Refrigerant Circuit with Expansion Valve and Evaporator

1. Evaporator
2. Expansion Valve
3. Valve for extracting, filling and measuring
4. Receiver/dryer with dryer bag/dryer cartridge
5. Condenser
6. A/C Compressor

Note

Arrows point in direction of refrigerant flow.

Refrigerant Circuit with Restrictor and Reservoir

1. A/C Compressor
2. Condenser
3. Restrictor
4. Evaporator
5. Reservoir with dryer bag

Note

Arrows point in direction of refrigerant flow.