Get Working with air conditioner service station -> 2.3 Performing gas analysis of refrigerant Guide for Volkswagen Scirocco SUV Third Generation (2008-2017)

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

♦ ⇒ “2.14 Checking pressures”, page 170

2.3

Performing gas analysis of refrigerant

Note

♦ For operation of the air conditioning system, it is important that

the refrigerant used has a certain degree of purity.

♦ Contamination with other refrigerants or gases can cause

damage and thereby failure of the air conditioning system.

♦ Contaminated refrigerant must be returned as gas of unknown

composition e.g. to your gas supplier for processing (or dis‐

posal) in accordance with legislative requirements ⇒ VW /

Audi-ServiceNet .

♦ To prevent liquid components (e.g. droplets of refrigerant oil)

in the extracted refrigerant gas from falsifying the result of the

gas analysis, separators (filters) are installed in the gas anal‐

ysis device that separate these droplets of liquid. Renew

separators in accordance with specifications of gas analysis

device or operating instructions of air conditioner service sta‐

tion ⇒ Operating instructions of gas analysis device or ⇒

Operating instructions of air conditioner service station .

All vehicles

– Connect the gas analysis device or air conditioner service sta‐

tion to the refrigerant circuit as instructed to do so, and bring

it into operation ⇒ Operating instructions of gas analysis de‐

vice ,

⇒ “2.2 Connecting air conditioner service station to refrigerant

circuit”, page 131 and / or ⇒ Operating instructions air condi‐

tioner service station .

– Perform the gas analysis as per the operating instructions.

Note

♦ A faulty gas analysis is possible from air in the refrigerant ho‐

ses or non-observance of the procedure for gas analysis as

detailed in the operating instructions.

♦ Carefully follow the operating instructions of the gas analysis

device / air conditioner service station .

♦ Evacuate refrigerant hoses of the air conditioner service sta‐

tion before connecting the service couplings to the refrigerant

circuit / gas cylinder with R1234yf refrigerant hose (see oper‐

ating instructions of gas analysis device / air conditioner serv‐

ice station

⇒ “2.3 Performing gas analysis of refrigerant”, page 134 .

The gas analysis may provide the following results:

♦ The R1234yf refrigerant complies with the specifications, the

planned measures may be performed with the air conditioner

service station .

♦ A fault occurred during the gas analysis. The fault is to be in‐

vestigated and rectified after which the gas analysis must be

repeated.

♦ The analysed R1234yf refrigerant does not comply with the

specifications, the analysed refrigerant must be extracted as

refrigerant of unknown composition and returned e.g. to your

gas supplier for processing (or disposal)

134

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

⇒ “6.2.17 Returning contaminated R1234yf refrigerant for

analysis, processing or disposal”, page 25

Note

♦ Should the analysis of the refrigerant - to be extracted e.g. from

the refrigerant circuit of a vehicle - indicate that it is contami‐

nated: you can also perform a gas analysis on the refrigerant

e.g. of another cylinder from your gas supplier if you wish to

verify the analysis result.

♦ Since R1234yf refrigerant is so pure, even small amounts of

ambient air in the charge hoses of the air conditioner service

station can falsify the results. For this reason, most air condi‐

tioner service stations have a feature via which the gas anal‐

ysis is repeated up to 2 times before a not OK result is

displayed ⇒ Operating manual for air conditioner service sta‐

tion .

♦ You can perform a simple function check on your gas analysis

device e.g. using ambient air (unscrew the service coupling

from the refrigerant hose with which the gas analysis is per‐

formed and analyse the gas with the refrigerant hose open).

The result of this test should then indicate that the analysed

gas is not OK.

♦ The method of gas analysis employed here was developed for

motor vehicle workshops. It provides no details about the pre‐

cise composition of the refrigerant. This gas analysis can

therefore only show how high the percentage of R1234yf re‐

frigerant is in the refrigerant analysed. If the percentage of

R1234yf is below 95%, the refrigerant does not comply with

the specifications and can cause damage to the components

of the refrigerant circuit. A gas analysis that also provides de‐

tails about the precise composition of the analysed refrigerant

is currently not available for workshops. Gas analyses with

which the precise composition of gases can be investigated

require complicated equipment and procedures and can usu‐

ally only be performed with dedicated testing facilities.

Should contaminated refrigerant be found during the gas analy‐

sis, notify the customer before continuing work and bring the

customer's attention to the following:

There is contaminated refrigerant or refrigerant of unknown com‐

position in the refrigerant circuit of his vehicle that does not

comply with the vehicle manufacturer's specifications. This re‐

frigerant:

♦ must be returned e.g. to the gas supplier as refrigerant of un‐

known composition for analysis, processing (or disposal)

⇒ “6.2.17 Returning contaminated R1234yf refrigerant for

analysis, processing or disposal”, page 25 .

♦ can be the cause of a malfunction or may already have caused

damage that makes the inevitability of malfunctions in the near

future probable.

♦ Depending on its composition, the use of contaminated refrig‐

erant could lead to the operating permit of the vehicle being

withdrawn.

♦ If, as a result of contaminated refrigerant, internal damage to

the refrigerant circuit has been caused (e.g. decomposition

products of the contaminated refrigerant have affected the

components of the refrigerant circuit

⇒ “1.5 Renewing components”, page 79 ), the refrigerant cir‐

cuit can only be restored to full functionality once all compo‐

nents that came into contact with the contaminated refrigerant

have been renewed. The internal condition of the refrigerant

circuit can be appraised e.g. by visually inspecting certain

2. Working with air conditioner service station

135

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

components of the refrigerant circuit (e.g. the condition of the

internal surfaces of removed refrigerant lines and refrigerant

hoses, the internal surface of the refrigerant reservoir and the

condition of the removed dryer cartridge).

♦ If internal damage has been caused to the refrigerant circuit

through contaminated refrigerant (e.g. failure of the air condi‐

tioner compressor has ensued owing to damaged control

elements or overheating, refrigerant oil has a stronger colour

than usual but the parts containing refrigerant have not been

affected ⇒ “1.5 Renewing components”, page 79 ), the refrig‐

erant circuit can be charged again once it has been flushed

(renew air conditioner compressor, dryer and expansion

valve). However, since there is no way of anticipating the long-

term effect of the contaminated refrigerant on the refrigerant

oil and the components of the refrigerant circuit, no guarantee

can be given in this case that the components of the refrigerant

circuit will function correctly in future.

♦ If the contaminated refrigerant has not caused internal dam‐

age to the refrigerant circuit (e.g. the refrigerant oil does not

have a stronger colour than usual, the components of the re‐

frigerant circuit have not been affected), the refrigerant circuit

can be charged again once the dryer has been renewed and

the refrigerant circuit has been evacuated for an extended pe‐

riod (at least 1 hour). However, since there is no way of

anticipating the long-term effect of the contaminated refriger‐

ant on the refrigerant oil and the components of the refrigerant

circuit, no guarantee can be given in this case that the com‐

ponents of the refrigerant circuit will function correctly in future

⇒ “1.5 Renewing components”, page 79 .

136

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

Note

♦ If there is a complaint that can be attributed to the contamina‐

ted refrigerant (e.g. leaking seals or hoses, damage to the air

conditioner compressor, contaminated refrigerant oil), the re‐

frigerant circuit must be flushed and then all components that

were damaged by the contaminated refrigerant (seals, hoses,

reservoir or dryer cartridge, expansion valve and air condi‐

tioner compressor) must be renewed. If it is found that the

contaminated refrigerant has affected other components as

well (e.g. the internal surfaces of the refrigerant pipes and re‐

frigerant hoses, damaged seals), the complete refrigerant cir‐

cuit must be renewed. The refrigerant circuit must then be

recharged with clean refrigerant. Then check the function of

the air conditioning system. For the customer and to safeguard

yourself, make a note that the refrigerant circuit was charged

with contaminated refrigerant.

♦ If there is a complaint that can be attributed to the contamina‐

ted refrigerant (e.g. loss or lack of cooling output) and no other

complaints can be found in the refrigerant circuit, or if the re‐

frigerant has to be extracted because work in the area of the

refrigerant circuit so requires, proceed as follows after evacu‐

ating the system. Remove the dryer and check for contami‐

nation. Since there could also be refrigerant oil on or in the

dryer, check this as well. If the refrigerant oil is contaminated,

dark or viscous or if deposits of dirt have built-up on the dryer,

flush the refrigerant circuit and renew the parts as described

above (damage may already have been caused, which could

soon lead to failure of the air conditioning system). If the re‐

frigerant oil is OK and the dryer is not contaminated any more

than is usual from normal operation, renew the dryer. Evacu‐

ate the refrigerant circuit for an extended period (at least 1

hour) and then recharge with clean refrigerant. Check the

function of the air conditioning system. For the customer and

to safeguard yourself, make a note that the refrigerant circuit

was charged with contaminated refrigerant.

2.4

Emptying refrigerant circuit

•

Depending on the type of equipment chosen, there may be

changes to the procedure (always follow user's manual for the

equipment being used) ⇒ Operating instructions air condi‐

tioner service station .

•

The refrigerant circuit should be emptied if parts of the refrig‐

erant circuit are to be removed, if it is unclear whether there is

refrigerant in the circuit, if contaminated refrigerant was de‐

termined during the gas analysis, or if safety precautions so

demand.

•

All of the operating instructions for work involving refrigerant

with the air conditioner service station can be found in the op‐

erating instructions of the air conditioner service station ⇒

Operating instructions air conditioner service station .

Draining

– On vehicles with high-voltage system, switch off “stationary air

conditioning” function (deactivate)⇒ Owner's Manual .

– Switch off ignition.

– Connect the air conditioner service station to the power sup‐

ply.

In addition for vehicles with electrically-actuated valves in the re‐

frigerant circuit that are not open when de-energised:

2. Working with air conditioner service station

137

Working with air conditioner service station -> 2.3 Performing gas analysis of refrigerant for Your Volkswagen Scirocco SUV Third Generation (2008-2017)

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