Tadano TR-800XXL4, Service Manual

Page: 213 / 402

K - 2
K - 2
Air Conditioner
30 W701-0220E
A/C system
trouble
phenomenon
Status explanation
of A/C system
pressure
Phenomenon explanation to
consider other factors
Diagnosis result (phenomenon of
principal cause)
Possible cause
Measures (specific
part name and
repair method)
------------------------------ TXV failure (blocking)
Remove blocked
foreign object, or
replace TXV and
R/D.
Will not get cold when driving
continuously, and repeats getting
cold after a while. Blow air volume
does not change.
Freezing of TXV by
contamination of water.
Replace R/D.
Deflate from circuit
and fill refrigerant.
Evaporator dirt and
blocking.
Wash or replace.
Air leakage between cooling
unit and heater unit.
Seal the joint with
repair tape or
packing agent.
Insufficient
cooling.
Both high
pressure and low
pressure low.
Bubble appears in sight glass, then
it changes transparently.
No air blow or air volume is few.
Blower electric circuit or
blower motor failure. Check and repair
circuit, or replace.
No cooling.
High pressure is
low, and low
pressure is high. High-pressure side and
low-pressure side will be balanced
after stopping compressor.
------------------------------
Compressor discharge
failure. Repair or replace
compressor.
------------------------------
TXV therms sensor tube
contacts to piping, or heat
insulation failure.
Improve contact of
therms sensor
part. Correct heat
insulation.
Replace therms
sensor tube
fixation clip.
Insufficient
cooling. Low pressure is
high.
Low-pressure piping is abnormally
cold and frosting. (refrigerant
returning)
-------------------------------
TXV adjustment failure
(raise too much) Readjust or
replace TXV.
Insufficient
cooling. (Normal
cooling at
beginning, and
gradually reduce
cooling later.)
--------------------
Blowing air volume changes
gradually. When A/C is OFF, and
blower is ON, much water is
drained from drain hose. Evaporator is frosting. Thermistor
is not cold. If louver blowing
temperature gets cold enough,
compressor will be OFF tentatively.
Turning OFF temperature of
thermostat has lowered.
Check thermistor,
thermo amp., and
mechanical
thermo.