Get Air conditioning system -> 1.4.2 Searching for leaks in refrigerant circuits using an electronic leak detector Guide for Volkswagen Touran 4 Door Second Generation (2015-2022)

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

Note

♦ VW/Volkswagen/Audi does not endorse the use of chemical

substances (leak inhibitor additives) for purposes of sealing

leaks in refrigerant circuits.

♦ Chemical substances used to seal leaks form deposits in the

refrigerant circuit. These can impair the function of the air con‐

ditioning system and cause the air conditioning system (and

your air conditioner service station ) to fail.

♦ These chemical substances (leak stop additives) react mostly

with the ambient air or the humidity to stop leaks in the refrig‐

erant circuit. They cause deposits to build up in the refrigerant

circuit (and your air conditioner service station ), cause valves

to malfunction and defects in other components with which

they come into contact. These deposits cannot be completely

removed from the components (not even by cleaning/flush‐

ing). The refrigerant circuit can only be repaired by replacing

all components that have come into contact with this sub‐

stance.

1.4.2

Searching for leaks in refrigerant circuits

using an electronic leak detector

Special tools and workshop equipment required

♦ Electronic leak detector or proprietary device

Note

♦ Leaks in R1234yf refrigerant circuits can only be found using

electronic leak detection devices designed for R1234yf refrig‐

erant.

♦ The various refrigerants have a different molecular structure.

The sensors of electronic leak detection devices are adapted

to these molecules. If an electronic leak detection device is

used that is not designed for R1234yf refrigerant, it will not

respond to R1234yf refrigerant at all or only in larger concen‐

trations in the vicinity of the leak. For this reason, electronic

leak detection devices designed only for R134a refrigerant

cannot be used for leak detection in the R1234yf refrigerant

circuit.

♦ Depending on the type of heater and air conditioner unit, a leak

from the evaporator can be investigated by holding the test

probe of the leak detector against the glove compartment

cooler connection in the heater and air conditioner unit, or by

holding the test probe against the open condensation drain

connection of the heater and air conditioner unit with the con‐

densation drain hose pulled off.

Performing leak detection on a completely empty refrigerant cir‐

cuit caused by a leak:

Note

With a completely empty refrigerant circuit, proceed as follows to

ensure that no more refrigerant than necessary enters the envi‐

ronment during testing:

– Evacuate refrigerant circuit using air conditioner service sta‐

tion ⇒ “2.5 Evacuating refrigerant circuit”, page 140 .

1. Refrigerant circuit

GETth

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

Note

♦ If a larger leak is detected during the evacuation process, de‐

termine the cause and rectify as described

⇒ “2.5 Evacuating refrigerant circuit”, page 140 .

♦ If during the evacuation process no leak is detected or a very

small leak is detected that cannot be located using the vacuum

test, proceed as follows.

– If the refrigerant circuit is completely empty, charge the system

with approx. 10% of refrigerant and perform leak detection in

the same way as per a fully charged refrigerant circuit

⇒ page 70 .

Performing leak detection on a charged refrigerant circuit:

– Switch off ignition.

– Start the leak detector according to the operating instructions.

– Always hold probe tip under location of suspected leak.

If, inherent of the design, the rate of clicks rises or a wailing noise

is heard, a leak has been detected ⇒ operating instructions for

leak detector .

Note

♦ Refrigerant gas is quickly dispersed by movement of air.

Draughts must therefore be avoided during leak detection.

♦ Refrigerant gas is heavier than air and therefore sinks at the

point at which it escapes.

Rep. gr.87 - Air conditioning system

GETth

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

1.4.3

Searching for leaks with UV leak detec‐

tion system

Note

♦ Certain leaks are difficult or impossible to find using an elec‐

tronic leak detection device. To investigate these leaks, leak

detection can be performed using the leak detection system

⇒ Electronic parts catalogue .

♦ Refrigerant and refrigerant oil leaks out of the refrigerant circuit

when the circuit has a leak. This oil generally remains in the

vicinity of the leak location. To make the oil visible under^lU^kV

light, a small amount of fluorescent fluid must be added to the

refrigerant circuit. This fluid (PAG oil with an additive which

lights up under UV light) is injected into the refrigerant circuit

and distributed with the refrigerant oil when the air conditioning

system is switched on.

♦ The air conditioning system must be operated for at least

60 minutes to ensure that the injected leak detecting additive

is distributed throughout the entire refrigerant circuit (air con‐

ditioner compressor must run). The leak may become visible

under UV light after a short period, but this depends on the

size of the leak.

♦ The refrigerant oil with additive, which lights up under UV light,

can be added directly in an open circuit or charged after emp‐

tying the circuit with air conditioner service station via the

service connection.

♦ If the leak detection additive is added to the refrigerant circuit

via the service connection, a small amount of leak detection

additive will be deposited in the service connection. Carefully

remove any deposits so that this area is not mistaken for a leak

during subsequent leak detection.

♦ If a component from a circuit in which leak detection additive

is filled is renewed, thoroughly clean the connection points to

other components after assembling the refrigerant circuit. Dur‐

ing subsequent leak detection, deposits of leak detection ad‐

ditive could otherwise be mistaken for leaks at the connecting

point.

♦ When purging the refrigerant circuit, refrigerant oil and there‐

fore also leak detection additive also enter the air conditioner

service station . The refrigerant oil is separated from the re‐

frigerant in the oil separator of the air conditioner service

station and removed from the air conditioner service station

via the drainage outlet. The drained refrigerant oil may not be

reused. It must be replaced with fresh refrigerant oil.

♦ If leak detection fluid was injected during a previous repair of

the refrigerant circuit, observe the following: do not inject new

leak detection fluid unless the refrigerant machine oil has been

replaced. If only some of the refrigerant machine oil was re‐

placed then only the respective amount of leak detection fluid

should be injected. If, for example, 100 ml of refrigerant oil is

replaced in a vehicle with 250 ml of refrigerant oil, inject only

1 ml (cm³) of leak detection additive.

♦ Certain materials and their compounds (e.g. oxidisation prod‐

ucts on components made from aluminium, corrosion protec‐

tion wax, etc.) also light up under UV light.

1. Refrigerant circuit

GETth

Air conditioning system -> 1.4.2 Searching for leaks in refrigerant circuits using an electronic leak detector for Your Volkswagen Touran 4 Door Second Generation (2015-2022)

Related Topics

Air conditioning system

Popular Owner Manuals

Latest Owner Manuals