118
8. Common trouble and troubleshooting of air conditioner system
The remedy and trouble analysis under abnormal pressure
No.
Pressure
Description
Analysis
Remedy
1
The high and low
pressure is lower than
normal.
There is bubble in the inspection
glass;the cold air in the bus
insufficient; high pressure pipe a
little bit warm and the low
pressure pipe a little bit cold, the
temperature difference is not too
much;
The refrigerant
filling is not
enough and the
system is leaking
Check the system for the
leakage and find out the
leaking point.
And make the maintenance
Fill in refrigerant
The high and low
pressure are higher than
normal
The refrigerant is
too much
Drain some part of the
refrigerant or refrigerant oil
2
The high and low
pressure are much lower
than normal.
No liquid flow seen from the
inspection glass;
Almost no refrigeration;
Almost no temperature difference
between high and low pressure
pipe
Air conditioner
system has serious
leakage
Check the system and find
out the leakage and fill the
enough refrigerant
3
The low pressure is
nearly to zero or even the
negative value; The high
pressure is lower than the
normal value
No refrigerate in the system
The front or the rear part of the
expansion valve has fog
expansion valve
blocked;
expansion valve
temperature
sensor damaged
or packing error
Changed the expanding
valve;
Change the expanding valve
temperature sensor;
Make good package for the
expanding valve.
The high pressure and
the low pressure are
abnormal; The pressures
are higher than the
normal values
The temperature of the sucking
pipe is lower than the normal
value and the frosting appeared
expansion valve
opened too much
Change the expanding valve;
Readjust the expanding
valve.
The high pressure is
higher than the normal
value and the low
pressure is lower than
normal
The surface for the air suction
pipe of the compressor has frost
or condensate
Expanding valve
damaged
Change the expanding valve.
4
The high and low
pressure are much higher
than the normal value
and the needle of the
gauge swing obviously
The cooling capability is
Insufficient and the system has
air and the bubbles seen in the
inspection glass
Air mixed in the
refrigerant The
vacuum is not good
for the first time
filling refrigerant or
after the
maintenance
Discharge the refrigerant in
the system and change
the desiccators and also
make the vacuum
repeatedly for filling the
refrigerant
