Get Air conditioning system Working with air conditioner service station -> 2.5 Evacuating refrigerant circuit Guide for Volkswagen Sharan VAN Second Generation (2010-2023)

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Air conditioning systems with refrigeranR1234yf - General information - Edition 07.2017

Note

♦ After opening the connecting points in the refrigerancircuit,

the open lines and componenconnections musbe closed (so

thathe ingress of moisture and dirin these components is

prevented).

♦ Sometimes, refrigeranoil is extracted from the refrigerancir‐

cuialong with the refrigeranand there is no way of stopping

this. To ensure lubrication of the air conditioner compressor,

the refrigeranoil quantity should be topped up with fresh oil.

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♦ Where vehicles are fitted with an air conditioner compressor

with air conditioner compressor regulating valve - N280- , the

engine should be run with the refrigerancircuiempty for no

longer than is absolutely necessary, making sure thahigher

engine speeds are avoided (since the air conditioner com‐

pressor will always run when the engine is running).

♦ On vehicles thahave an air conditioner compressor with air

conditioner compressor regulating valve - N280- , the engine

may only be started with a completely assembled refrigeran

circuit, ensuring thahigher engine speeds are avoided.

2.5

Evacuating refrigerancircui

•

The procedure described in the operating manual for your air

conditioning service station is to be followed ⇒ Operating

manual for air conditioner service station .

The refrigeranoil volume in the air conditioner service station

has been checked and, if necessary, adjusted ⇒ Operating

instructions of air conditioner service station .

The refrigeranvolume in the air conditioner service station

has been checked and, if necessary, adjusted ⇒ Operating

manual of air conditioner service station .

Before the refrigerancircuiis filled with refrigerant, imusbe

evacuated, i.e. completely emptied of air. In the process, all mois‐

ture is drawn ouof the circuit.

Leaks can be determined when evacuating the refrigerancircui

⇒ “1.4 Investigating leaks”, page 68 .

NOTICE

Risk of damage to air conditioner compressor with negative

pressure in the refrigerancircuit.

– Never starthe engine if there is negative pressure in the

refrigerancircuit.

Evacuating:

•

The refrigerancircuiis completely assembled.

– 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‐

frigerancircuithaare noopen when de-energised:

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Air conditioning systems with refrigeranR1234yf - General information - Edition 07.2017

Note

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♦ On vehicles with high-voltage system and auxiliary air condi‐

tioning system functions (“heapump mode” or “cooling of

high-voltage battery”), valves may be installed in the refriger‐

ancircuithaare noopen when de-energised. These valves

are opened and closed e.g. via incremental motors and are no

longer actuated when the ignition is switched off. To empty

completely, to evacuate correctly and to charge the refrigeran

circuit, however, no areas may be isolated, which is why these

valves musbe opened before work is carried ou⇒ Heating,

air conditioning; Rep. gr. 87 ; Refrigerancircui(vehicle-spe‐

cific workshop manual) and ⇒ Vehicle diagnostic tester in

“Guided FaulFinding” mode.

♦ Non-return valves in the refrigerancircuihave a certain hold‐

ing pressure in the direction of flow (approx. 0.1 bar or

100 mbar). To ensure thathe refrigerancircuican be evac‐

uated completely (residual pressure below 5 mbar), all of the

electrically actuated valves mustherefore be open.

– Use the vehicle diagnostic tester to open the electrically-ac‐

tuated valves thaare noopen when de-energised ⇒ Vehicle

diagnostic tester in “Guided FaulFinding” mode.

All vehicles

– Bring the air conditioner service station into operation as de‐

scribed in the instructions ⇒ Operating instructions air condi‐

tioner service station .

– Unscrew the sealing caps from the service connections of the

refrigerancircui(see vehicle-specific refrigerancircuit) ⇒

Heating, air conditioning system; Rep. gr. 87 ; Refrigerancir‐

cui(vehicle-specific workshop manual).

– Check service connections of refrigerancircuifor contami‐

nation or corrosion, clean if necessary.

Note

Diror a rough surface on the service connections caused by cor‐

rosion can cause damage to the seals and thereby premature

failure of the quick-release couplings.

– Connect the air conditioner service station to the refrigeran

circui

⇒ “2.2 Connecting air conditioner service station to refrigeran

circuit”, page 131 .

– Switch on the air conditioner service station , evacuate the re‐

frigerancircuiand perform the vacuum tes(for a period of

e.g. 10 minutes with the vacuum pump on to remove any air,

remains of refrigeranand moisture and 20 minutes for the

vacuum/pressure increase check).

2. Working with air conditioner service station

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Air conditioning systems with refrigeranR1234yf - General information - Edition 07.2017

Note

♦ The vacuum athe end of the evacuating process (running of

vacuum pump of air conditioner service station ) musbe less

than 5 mbar absolute pressure. Should pressure during the

evacuating process in the refrigerancircuinobe less than

5 mbar, this could have various causes. For example, leaks in

the refrigerancircuior in the connection to the air conditioner

service station , the time for the evacuating process is setoo

short, the vacuum pump of the air conditioner_lkservice station

does nogenerate the necessary vacuum or the vacuum sen‐

sor of the air conditioner service station is nocalibrated prop‐

erly ⇒ Operating instructions air conditioner service station .

♦ An absolute pressure of 5 mbar equates to a vacuum of

975 mbar aan ambienpressure e.g. of 980 mbar.

♦ Athe end of the vacuum/pressure increase check, pressure

in the refrigerancircuishould nobe greater than 20 mbar

absolute. Should the pressure in the refrigerancircuibe

greater than 20 mbar during the vacuum/pressure increase

check, the vacuum pump is switched on and the process is

repeated from the beginning ⇒ Operating instructions air con‐

ditioner service station . Should pressure in the refrigeran

circuistill nobe less than 20 mbar even after the process has

been repeated twice, this could have various causes. For ex‐

ample, there could be leaks in the refrigerancircuit, a leak in

the connection from the refrigerancircuito the air conditioner

service station or in the air conditioner service station itself,

the time sefor the evacuating process is too shorand the

time sefor the vacuum/pressure increase check is too long.

♦ If there is reason to suspeca leak in the refrigerancircuit,

switch off the air conditioner service station if necessary and

allow ito stand for as long as possible (e.g. for aleas1 hour

to check the leak-tightness of the refrigerancircuit) ⇒ Oper‐

ating instructions air conditioner service station .

♦ Depending on the version of air conditioner service station ,

the pressure in the refrigerancircuiis displayed directly.

However, there is also a chance thathe currenpressure is

only displayed while the vacuum pump is running ⇒ Operating

instructions air conditioner service station . In the evenof an

air conditioner service station only displaying the ambien

pressure, the display of the pressure in the refrigerancircui

will depend on the ambienpressure during activation (ambi‐

enpressure a980 mbar, a vacuum of 975 mbar equates to

a residual pressure of 5 mbar absolute).

♦ If the refrigerancircuiwas opened, small quantities of mois‐

ture may have entered the refrigerancircuit. In this case, the

refrigerancircuiis to be evacuated for aleas30 minutes

(pressure in the refrigerancircuibefore charging musbe less

than 20 mbar).

♦ If the refrigeranwas extracted (to check the fill volume) and

the refrigerancircuiwas only evacuated so thaicould be

recharged (the refrigerancircuiwas noopened and is leak-

tight), iis sufficiento evacuate the refrigerancircuifor 5

minutes and to seno time or only a shortime (e.g. 1 minute)

for the vacuum/pressure increase check (no air or moisture

entered the refrigerancircuit).

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♦ Depending on the volume of refrigeranoil in the refrigeran

circuit, the age and mileage of the vehicle, the layouof the

refrigerancircuietc., there is a chance with a leak-tighre‐

frigerancircuiof the specified absolute pressure in the re‐

frigerancircuinorising above the prescribed 20 mbar owing

to refrigeranevaporating ouof the refrigeranoil. Should this

be the case, repeathe process again if necessary and / or

adapthe presetimes accordingly.

If the vacuum display does nochange (and the pressure stays

below 20 mbar), the system is leak-tighand can be recharged.

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Note

♦ Depending on the version of air conditioner service station ,

the currenpressure in the refrigerancircuiis permanently

displayed or only displayed after switching on e.g. the “Evac‐

uate” function ⇒ Operating instructions air conditioner service

station .

♦ Due to the high degree of evacuation, there is a chance tha

refrigeran- which evaporates from the refrigeranoil - could

elevate the pressure in the refrigerancircuiduring the vac‐

uum tesfrom 20 to 40 mbar (absolute pressure). This is no

indication of a leak in the refrigerancircuit, though depending

on the version of air conditioner service station icould trigger

a fault. If necessary, evacuate the refrigerancircuiagain and

observe the vacuum display for an extended period. Only if the

vacuum remains steady and you are certain thathe refriger‐

ancircuiis leak-tighis ipermissible to charge the system.

– Charge the refrigerancircuiwith air conditioner service sta‐

tion ⇒ “2.6 Charging refrigerancircuit”, page 146 .

If the vacuum does noremain or sufficienpressure cannobe

built-up, the following action is required:

♦ If pressure in the refrigerancircuionly rises slowly after evac‐

uating e.g. owing to refrigeran(or moisture) evaporating from

the refrigeranoil, evacuate the refrigerancircuiagain and

observe the vacuum gauge for an extended period.

– If there is any doubas to whether the refrigerancircuiis ac‐

tually leak-tight, evacuate again and observe the vacuum

gauge for an extended period. Only when a vacuum is main‐

tained can charging commence.

– Only if you are really sure thathe refrigerancircuiis leak-

tighshould the system be charged

⇒ “2.6 Charging refrigerancircuit”, page 146 .

Further action if a leak is detected during evacuation:

♦ If there is a leak so major thaicauses air to escape to such

a degree during evacuation thathe air conditioner service

station is incapable of generating a sufficienvacuum or the

vacuum gauge indicates immediately after switching off the air

conditioner service station thaair has entered the system and

negative pressure is lost.

– Investigate the leak in the refrigerancircuias follows:

2. Working with air conditioner service station

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Air conditioning systems with refrigeranR1234yf - General information - Edition 07.2017

Note

♦ A larger leak in the refrigerancircuican be detected, for ex‐

ample, by pressurising the circuito a maximum of 15 bar using

cleaned and dried compressed air or nitrogen ⇒ page 124 . If

the leak is large enough, the leakage poincan be detected by

sound as the gas escapes.

♦ The compressed air or nitrogen is introduced to the closed,

empty refrigerancircuivia the service connection -B- to which

through a quick-release coupling adapter -A- has been con‐

nected.

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♦ Screw the handwheel -C- into the quick-release coupling

adapter -A- until the valve in the service connection -B- is

completely open - do noover tighten the valve.

♦ The quick-release coupling adapter for service connection can

be fitted e.g. with a modified charging hose -A- (for example

with a M12 x 1.5-6G thread in accordance with SAE J639)

depending on the thread of the quick-release coupling adapter

and a suitable adapter -B- to connecto the workshop com‐

pressed air system ⇒ page 259 . To ensure thano moisture,

oil and dirfrom the workshop compressed air system enter

the refrigerancircuiof the air conditioning system, use e.g. a

combination fine filter unifor compressed air systems with an

oil, dirand water separator, which is commonly used in pain

spraying facilities. Install this between the compressed air sys‐

tem and the charge hose -A- ⇒ Electronic parts catalogue .

♦ Using the manifold gauge with pressure reducer for nitrogen

(maximum reduced pressure: 15 bar) -1- you can conneca

full nitrogen gas cylinder -3- via a charge hose -2- (e.g. with

M12 x 1.5-6G thread in accordance with SAE J639) to the

service connection - to which a quick-release coupling adapter

is connected - of a closed, empty refrigerancircui

⇒ page 258 .

– Slowly increase the pressure in the refrigerancircuito a max‐

imum of 15 bar.

CAUTION

Risk of injury from nitrogen escaping under high pressure.

– Use pressure limiter for nitrogen tank.

– Search for the leak by sound, which can be heard as gas es‐

capes from this point.

– Repair the leak.

– Evacuate refrigerancircuiand observe the vacuum gauge

over a period of hours. Only when a vacuum is maintained can

charging commence.

♦ If a leak is presenof a size where no or very little air is drawn

in - with the refrigerancircuievacuated - and the air condi‐

tioner service station can create sufficienvacuum. The vac‐

uum gauge does noincrease or increases very slowly after

switching the air conditioner service station off. This indicates

thathere may be a very small ingress of air and the vacuum

is lost.

2. Working with air conditioner service station

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Air conditioning systems with refrigeranR1234yf - General information - Edition 07.2017

– Charge the circuiwith 100 g of refrigeranand search for the

possible leak using an electronic leak tester

⇒ “1.4.2 Searching for leaks in refrigerancircuits using an

electronic leak detector”, page 69 or add an approved UV

contrassubstance to the refrigeranand search for the pos‐

sible leak in the circuiusing the leak detector system

⇒ “1.4.3 Searching for leaks with UV leak detection system”,

page 71 .

– Evacuate refrigerancircuiif necessary

⇒ “2.4 Emptying refrigerancircuit”, page 137

– Rectify the problem in the refrigerancircui⇒ Heating, air

conditioning; Rep. gr. 87 ; Refrigerancircui(vehicle-specific

workshop manual).

– Evacuate the refrigerancircuiand observe the vacuum

gauge over an extended period. Only when a vacuum is main‐

tained can charging commence

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⇒ “2.5 Evacuating refrigerancircuit”, page 140 .

If iis necessary after evacuating to perform work on the vehicle

for which the air conditioner service station is norequired:

– Detach the air conditioner service station from the refrigeran

circuiand switch off

⇒ “2.8 Switching off air conditioner service station and sepa‐

rating from refrigerancircuit”, page 151 .

NOTICE

Risk of damage to air conditioner compressor with negative

pressure in the refrigerancircuit.

– Never starthe engine if there is negative pressure in the

refrigerancircuit.

– Ensure that, until the refrigerancircuiis charged, the engine

cannobe started.

If after emptying and evacuating the refrigerancircuiis to be

recharged ⇒ “2.6 Charging refrigerancircuit”, page 146 .

2.6

Charging refrigerancircui

Note

♦ The whole amounof refrigerancan be charged either on the

high pressure side or the low pressure side. Charging of the

refrigerancircuiis described as follows for the high pressure

side.

♦ Fill capacities of refrigeranand refrigeranoil ⇒ Heating, air

conditioning; Rep. gr. 00 ; Technical data .

•

The procedure described in the instruction manual for the air

conditioning service station is to be followed ⇒ Operating in‐

structions of air conditioner service station .

Before charging the system with refrigerant, the amounof re‐

frigeranoil musbe adjusted ⇒ Heating, air conditioning; Rep.

gr. 00 ; Technical data .

Ensure when charging the refrigerancircuithathe air con‐

ditioner service station is athe same level as the vehicle

whose refrigerancircuiis to be charged (no greater than 50

cm difference). If the heighdifference is too great, deviations

may occur between the amounof refrigerandisplayed and

the amounactually charged (depending on the version of air

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Air conditioning system Working with air conditioner service station -> 2.5 Evacuating refrigerant circuit for Your Volkswagen Sharan VAN Second Generation (2010-2023)

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