Content .. 14 15 16 17 ..

SANY Crawler Hydraulic Excavator SY215CLC (CUMMINS QSB6.7 engine). Shop Manual - page 16

Structure and Function

SY215C

4-156

6. Fault testing with manifold pressure gauge

●

Refrigerating system under normal condi-
tion

Gauge reading:

Lo-pressure end:

0.15~0.25 Mpa (1.5~2.5 Kgf/cm²)

Hi-pressure end:

1.37~1.57 Mpa (14~16 Kgf/cm²)

After the engine has been preheated, read the
pressure value on the gauge under the follow-
ing conditions:

1) Temperature at air inlet: 30 – 35°C

2) Engine speed: 1500 rpm

3) Fan speed: High

4) Temperature control: Minimum.

5) Air circulation mode: Recirculation

ZX215-1002167

MPa

{cmHg kgf/cm

}

{cmHg kgf/cm

}

-01

-76

-50

R134a

085

8.5

Structure and Function

SY215C

4-157

Symptom

Cause

Analysis

Remedy

●

When the system is
operating, pressure
at the Lo-pressure
end unstable (some-
times vacuum,
sometimes normal)

●

Moisture in the system
ices up at the expan-
sion valve causing
circular temporary
stop. When ice melts,
the system becomes
normal again.

●

Over-saturation of de-
hydrator.

●

Moisture in the system
ices up at the expan-
sion valve and hinders
the circulation of the
refrigerating system.

●

Replace receiver/
dehydrator

●

Remove the mois-
ture in the system
through constant
pumping.

●

Add proper volume
of new refrigerant.

●

Moisture in the refrigerating system

Symptom: Intermittent refrigeration to non-refrigeration

ZX215-1002168

MPa

{cmHg kgf/cm

}

{cmHg kgf/cm

}

-01

-76

-50

085

8.5

Structure and Function

SY215C

4-158

●

Insuf

cient refrigeration

Symptom: Insuf

cient refrigeration

Symptom

Cause

Analysis

Remedy

●

Pressure at both Hi- and
Ho-pressure ends very
low

●

Foam is continuously ob-
served via the sight glass

●

Insuf

cient refrigeration.

●

Air leaks
somewhere
in the refrig-
erating sys-
tem

●

Insuf

cient

refrigerant in the
system

●

Leak of refriger-
ant

●

Check for air leakage with a leak
detector. Make necessary re-
pairs.

●

Add proper amount of refriger-
ant.

●

When connected with the gauge,
if the reading is near zero, set
the system under vacuum state
after inspection and repair.

ZX215-1002169

MPa

{cmHg kgf/cm

}

{cmHg kgf/cm

}

-01

-76

-50

085

8.5

Structure and Function

SY215C

4-159

●

Defective refrigerant circulation

Symptom: insuf

cient refrigeration

Symptom

Cause

Analysis

Remedy

●

Pressure at both
Hi- and Lo-pressure
sides very low

●

Frosting on the pip-
ing between parts
and reservoir

●

Contaminant in the
reservoir hinders the

ow of refrigerant.

●

Blocked reservoir

●

Replace reservoir

ZX215-1002170

MPa

{cmHg kgf/cm

}

{cmHg kgf/cm

}

-01

-76

-50

085

8.5

Structure and Function

SY215C

4-160

●

Refrigerant not circulating

Symptom: Non-refrigeration (intermittent refrigeration)

Symptom

Cause

Analysis

Remedy

●

Vacuum at Lo-pres-
sure side; pressure
at Hi-pressure side
extremely low

●

Frosting or conden-
sation on the pipes
around the expan-
sion valve or receiv-
er/dehydrator

●

Moisture or contami-
nant in the refrigerant
hinders the

ow of

refrigerant.

●

Air leak at the thermal
pipe of the expansion
valve hinders the

of refrigerant.

●

Refrigerant not
circulating

●

Check the expansion valve
and ERP.

●

Blow the contaminant in the
expansion valve or replace
the expansion valve if nec-
essary.

●

Replace the receiver

●

Release internal air and
add refrigerant. If air leaks
from thermal pipe, replace
expansion valve.

ZX215-1002171

MPa

{cmHg kgf/cm

}

{cmHg kgf/cm

}

-01

-76

-50

085

8.5

Structure and Function

SY215C

4-161

●

Over-charging of refrigerant or insuf

cient refrigeration of condenser

Symptom: Insuf

cient refrigeration

Symptom

Cause

Analysis

Remedy

●

Pressure at both Hi-
and Lo-pressure
sides very high

●

No foam can be ob-
served via the sight
glass even when
engine speed drops.

●

Over-

lling of refriger-

ant in the system. Re-
frigerating performance
inadequate.

●

Insuf

cient refrigera-

tion of condenser

●

Over-

lling of refriger-

ant

●

Condenser

ns clogged

or fan motor error.

●

Clean the condenser

●

Check the working
condition of fan mo-
tor

●

If the two above
items are normal,
check the volume
of refrigerant. Add
refrigerant.

ZX215-1002172

MPa

{cmHg kgf/cm

}

{cmHg kgf/cm

}

-01

-76

-50

085

8.5

Structure and Function

SY215C

4-162

●

Air is observed in the refrigerating system

Symptom: Poor refrigeration

If refrigerant is added with no evacuation operation performed, the following gauge reading

will appear:

Symptom

Cause

Analysis

Remedy

●

Pressure at both Hi- and
Lo-pressure ends very
high

●

Lo-pressure piping feel-
ing hot

●

Foam is observed
through the sight glass

●

Air enters the re-
frigerating system

●

Air enters the refriger-
ant system

●

Insuf

cient evacuation

●

Check if compressor
oil is contaminated
or inadequate.

●

Evacuate and add
new refrigerant.

ZX215-1002173

MPa

{cmHg kgf/cm

}

{cmHg kgf/cm

}

-01

-76

-50

085

8.5

Structure and Function

SY215C

4-163

●

Improper installation of expansion valve/thermal pipe defect (wide opening)

Symptom: insuf

cient refrigeration

Symptom

Cause

Analysis

Remedy

●

Pressure at both
Hi- and Lo-pressure
ends very high

●

Frosting or conden-
sation on Lo-pres-
sure piping

●

Expansion valve de-
fect, or improper instal-
lation of thermal pipe

●

Over-

lling of

refrigerant in
Lo-pressure
piping

●

Expansion
valve opening
very wide

●

Check the installation of
thermal piping

●

If thermal piping is normal,
check the expansion valve.
Replace defective expan-
sion valve if observed.

ZX215-1002174

MPa

{cmHg kgf/cm

}

{cmHg kgf/cm

}

-01

-76

-50

085

8.5

Structure and Function

SY215C

4-164

●

Compressing error

Symptom: No refrigeration

Symptom

Cause

Analysis

Remedy

●

Pressure at Lo-pressure
side very high

●

Pressure at Hi-pressure
side very low

●

Compressor internal
leakage

●

Compressing fault;

●

Leaking or damaged
valve, loosened parts

●

Repair or replace
compressor

ZX215-1002175

MPa

{cmHg kgf/cm

}

{cmHg kgf/cm

}

- 01

-01

-76

-50

085

8.5

Structure and Function

SY215C

4-165

4.7.14 Compressor oil

Oil shall be added into the A/C system for
lubrication. Compressor oil is solved in the
refrigerant and circulates in the system. When
the air conditioning system is shut down, com-
pressor oil will stay inside the components. If
no compressor oil is added into the system
when replacing components, inadequate lubri-
cation will result. Add compressor oil accord-
ing to the chart below:

●

Add oil into a new compressor ac-
cording to the required volume of the
system. When the compressor is to be
replaced, discharge the surplus oil in it.

●

Over-filling of compressor oil will re-
duce the refrigerating capacity. Short of
compressor oil in the system will cause
compressor abnormality.

●

Protect pipe joints and O-rings from
contamination when disassembling the
compressor.

Replaced component

Compressor

Condenser

Evaporator

Volume(CC)

See "CAUTION" below

Compressor oil grade

ND8# (10P, 10PA, 10S series compressor)

ND9#(TV series compressor)

CAUTION

Structure and Function

SY215C

4-166

4.8

Engine Control

1- Battery relay
2- Battery
3-  Engine start switch
4-  Fuel control dial
5- Start motor
6- Engine controller
7-  Fuel injection pump
8- Throttle motor
9- Shutdown device

Outline

●

Start and stop the engine only with the en-
gine start switch (3).

●

The controller (6) receives the signal from
the fuel control dial (4) and transmits the
drive signal to the throttle motor (8) to
control the governor lever angle of fuel
injection pump (7) and control the engine
speed.

●

When engine start switch (3) is turned to
the OFF position, the shutdown device (9)
closes the injection nozzle of the fuel injec-
tion pump and cuts the engine fuel supply.
Then, the engine stops.

ZX215-1002176

Structure and Function

SY215C

4-167

4.8.1 System operation

4.8.1.1 Engine startup

●

When the start switch is turned to the
START position, the starting signal is trans-
mitted to the start motor. Then, the start
motor rotates to start the engine.
When it happens, the engine controller
checks the signal voltage from the fuel
control dial and sets the engine speed to
the speed set by the fuel control dial.

4.8.1.2 Engine speed control

●

The fuel control dial sends a signal voltage
corresponding to the rotation angle to the
engine controller.

The engine controller sends a driving
signal to the throttle motor according to the
signal voltage to control the fuel injection
pump, and eventually controls the engine
speed.

4.8.1.3 Engine shutdown

●

When the start switch is turned to the OFF
position, the controller activates the shut-
down device to cut off the fuel supply and
stops the engine.

ZX215-1002177

(Regulating signal

)

Engine

(Power)

Controller

(Start switch ON signal)

(Starting signal)

Start S/W

Fuel ctrl dial

Throttle On

Governor
motor

Alternator

Bat. relay

Lock
relay

Shutdown
device

Shutdown

relay

(Starting signal)

Safety
relay

Drive signal

(Potentiometer singal)

Throttle Off

Pilot S/W

Start motor

Starting relay

ZX215-1002178

Throttle On

(Regulating signal

)

Governor
motor

Alternator

Bat. relay

Lock
relay

Engine

(Power)

Controller

(Start switch ON signal)

Start motor

Shutdown
device

Shutdown

relay

(Starting signal)

Safety
relay

Drive signal

(Potentiometer singal)

Throttle Off

Starting relay

Pilot S/W

Start S/W

Fuel ctrl dial

ZX215-1002179

Throttle On

(Regulating signal

)

Governor
motor

Alternator

Bat. relay

Lock
relay

Engine

(Power)

Controller

(Start switch ON signal)

Start motor

Shutdown
device

Shutdown

relay

(Starting signal)

Safety
relay

Throttle Off

Starting relay

Pilot S/W

Start S/W

Fuel ctrl dial

Structure and Function

SY215C

4-168

4.8.2

Components

4.8.2.1

Fuel control dial

1- Knob
2- Dial
3- Spring

4- Ball
5- Potentiometer
6- Connector

ZX215-1002180

25°

140°

9×10°

Yellow

Blue

Red

Level 1

Left limit

Right limit

Level 10

Structure and Function

SY215C

4-169

Function

●

Turning of the fuel control dial changes the
resistance of the sliding rheostat inside the
dial and the voltage signal collected by the
controller. The controller calculates the col-
lected signals and drives the throttle motor
via signal output and controls the volume
of the injection pump so that the engine
can run at an optimal speed.

●

When throttle voltage is beyond the area,
the controller sends out alarm code and
the engine runs at low idle. The area under
the sloping line is the abnormality detection
area.

Remark:

The left limit is 0%; and the right limit is 100%.

ZX215-1002181

100

0.25 1.72

4.49 4.75 5

Voltage

（

）

Dial angle

Structure and Function

SY215C

4-170

4.8.2.2

Controller

Controller port layout

ZX215-1002182

TYPE

USE FOR
NO

ZX215-1002183

........

...................

Structure and Function

SY215C

4-171

Pin

No.

Signal name

Input/

output

Rear pump pressure sensor

Input

Sensor power ground

Input

Sensor power ground

Input

Sensor power

Output

Monitor CAN Low

Calibrator CAN High

Calibrator CAN Low

Coolant temp very high

Input

R. travel pressure sensor

Input

Swing pressure sensor

Input

Bucket CURL pressure sensor

Input

Boom RAISE pressure sensor

Input

Arm IN pressure sensor

Input

Front pump pressure sensor

Input

Sensor PWR ground

Sensor PWR

Output

Sensor PWR

Output

State indicator

Monitor CAN High

Monitor CAN Low

Setting tool CAN Low

Setting tool CAN shield wire

Setting tool CAN High

Pin

Signal name

Input/

output

Travel speed switching solenoid

Front pump solenoid valve

Rear pump solenoid valve

Swing priority solenoid valve

Bucket con

uence solenoid valve

Boom priority 1

100 Boom priority 2
104 Motor drive signal +

113 Motor drive signal -
114 Power ground
115 Power ground
116 Power ground
117 Power ground
118 Power supply(24V constant)
119 Power supply(24V constant)

120 Power supply(24V constant)
121 Power supply(24V constant)

Pin

No.

Signal name

Input/

output

Power ground

Power supply(24V constant)

Input

Power supply(24V constant)

Input

Fuel level sensor

Input

Throttle position signal

Input

Engine speed signal

Input

RS232 ground

RS232 receive

Enable

Coolant temperature sensor signal Input

Oil temperature sensor signal

Input

Backup pilot pressure signal

Input

Fuel dial signal

Input

Engine speed signal ground

RS232 send

CPU mode

Enable

Engine oil pressure switch

Input

L. travel pressure sensor

Input

Bucket DUMP pressure sensor

Input

Boom LOWER pressure sensor

Input

Arm OUT pressure sensor

Input

Input and output signals

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