refrigerant1.pdf

55–6

HEATER & AIR CONDITIONER

–

REFRIGERANT

ON–VEHICLE INSPECTION

550IQ–01

INSPECT REFRIGERANT PRESSURE WITH MAN-

IFOLD GAUGE SET

(a)

This is a method in witch the trouble is located by using

a manifold gauge set. Read the manifold gauge pressure

when the these conditions are established.

Test conditions:

Temperature at the air inlet with the switch set

at RECIRC is 30 – 35 ° C (86 – 95 ° F)

Engine running at 1500 rpm

Blower speed control switch at ”HI” position

Temperature control dial at ”COOL” position

A/C switch ON

Fully open doors

(1) Normally functioning refrigeration system.

Gauge reading:

Low pressure side:

0.15 – 0.25 MPa (1.5 – 2.5 kgf/cm 2 )

High pressure side:

1.37 – 1.57 MPa (14 – 16 kgf/cm 2)

E50573

(2)

Moisture present in refrigeration system.

Condition : Periodically cools and then fails to cool

I22117

Symptom

Probable cause

Diagnosis

Remedy

Moisture in refrigerating system

freezes at expansion valve orifice

causing a temporary stop of cycle,

however, when it melts, normal

state is restored.

Drier in oversaturected state

(1) Replace condenser

(2) Remove moisture in cycle by

repeatedly evacuating air

(3) Supply proper amount of new

refrigerant

During operation, pressure on low

pressure side sometimes become

a vacuum and sometime normal

Moisture in refrigerating system

freezes at expansion valve orifice

and blocks circulation of refriger-

ant

2004 COROLLA (RM1037U)

Author:

Date:

1576

55–7

HEATER & AIR CONDITIONER

–

REFRIGERANT

(3)

Insufficient cooling

Condition: Cooling system does not function eftectively.

I22118

Symptom

Probable cause

Diagnosis

Corrective Actions

(1) Check for gas leakage and re-

pair if necessary

(2) Supply proper amount of new

refrigerant

(3) If indicated pressure value is

close to a 0 when connected to

gauge, create the vacuum after in-

specting and repairing location of

leak

Pressure low on both low and

high pressure sides

Insufficient cooling performance

Gas leakage in refrigeration sys-

tem

Insufficient refrigerant

Refrigerant leaking

(4)

Poor circulation of refrigerant

Condition: Cooling system close not function effectively.

I22119

Symptom

Probable cause

Diagnosis

Corrective Action

Pressure low on both low and

high pressure sides

Refrigerant flow obstructed by dirt

in receiver

Receiver clogged

Replace condenser

Frost on pipe from condenser to

unit

2004 COROLLA (RM1037U)

Author:

Date:

1577

55–8

HEATER & AIR CONDITIONER

–

REFRIGERANT

(5)

Refrigerant does not circulate

Condition: Cooling system does not function. (Sometimes it way function)

I22120

Symptom

Probable cause

Diagnosis

Corrective Actions

(1) Check expansion valve

(2) Clean out dirt in expansion

valve by air blowing

(3) Replace condenser

(4) Evaporate air and supply prop-

er amount of new refrigerant.

(5) For gas leakage from expan-

sion valve, replace expansion

valve

Vacuum indicated on low pres-

sure side, very low pressure indi-

cated on high pressure side

Frost or dew seen on piping be-

fore and after receiver/ drier or ex-

pansion valve

Refrigerant flow obstructed by

moisture or dirt in refrigerating sys-

tem

Refrigerant flow obstructed by

gas leaked from expansion valve

Refrigerant does not circulate

(6)

Refrigerant overcharged or insufficient cooling of

condenser

Condition: Cooling system does not function dftectively.

I22121

Symptom

Probable cause

Diagnosis

Remedy

(1) Clean condenser

(2) Check cooling fan with cooling

fan motor operation

(3) If (1) and (2) are in normal

state, check amount of refrigerant

and supply proper amount of re-

frigerant

Excessive refrigerant in

cycle

Unable to develop sufficient per-

formance due to excessive use of

refrigerating system

too much refrigerant sup-

Pressure too high on both low

and high pressure sides

plied

Condenser cooling

insufficient

condenser fins

clogged at cooling fan

Insufficient cooling of condenser

2004 COROLLA (RM1037U)

Author:

Date:

1578

55–9

HEATER & AIR CONDITIONER

–

REFRIGERANT

(7)

Air present in refrigeration system

Condition: Cooling system does not function.

NOTE : These gauge indica-

tions are shown when the

refrigerating system has

been opens and the refriger-

ant charged without vacuum

purging.

I22122

Symptom

Probable cause

Diagnosis

Corrective Actions

(1) Check compressor oil to see if

it is see if it is dirty or insufficient

(2) Evacuate air and supply new

refrigerant

Pressure too high on both low

and high pressure sides

The low pressure piping too hot

to the touch

Air present in refrigerating sys-

tem

Insufficient vacuum purging

Air entered in refrigerating system

(8)

Expansion valve improperly

Condition: Refrigerant functions insufficient.

I22123

Symptom

Probable cause

Diagnosis

Corrective Actions

Pressure too high on both low

and high pressure sides

Frost or large amount of dew on

piping on low pressure side

Excessive refrigerant in low

pressure piping

Expansion valve opened too

wide

Trouble in expansion valve

Check expansion valve

2004 COROLLA (RM1037U)

Author:

Date:

1579

55–10

HEATER & AIR CONDITIONER

–

REFRIGERANT

(9)

Defective compression compressor

Condition : Refrigerant is not effective.

I22124

Symptom

Probable cause

Diagnosis

Corrective Actions

Pressure too high on low high

pressure sides

Pressure too low to on high pres-

sure side

Compression failure

Internal leak in compressor

Leakage from valve damaged or

broken sliding parts

Repair or replace compressor

Gauge readings (Reference)

Pressure on low pressure side

MPa (kgf/cm 2 )

0.5 (5.0)

Blower HI Zone

0.4 (4.0)

1.06 (10.9)

0.3 (3.0)

0.27 (2.85)

1.2 (12.3)

0.22 (2.25)

0.2 (2.1)

Blower LO Zone

0.2 (2.0)

1.25 (12.8)

0.14 (1.5)

1.32 (13.5)

Pressure on HI

pressure side

0.5 (5.0)

1.0 (10.0)

1.5 (15.0)

2.0 (20.0)

MPa (kgf/cm 2 )

I30081

2004 COROLLA (RM1037U)

Author:

Date:

1580

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