Service manual
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3.9.2 Automatic PTI (Pre-Trip Inspection)
● The automatic PTI function is provided so as to ensure correct inspection and to shorten inspection
time.
(1) Appearance inspection of unit
q Physical damage
w Casing insulation through hole area
e Drain hose (dust and clogging)
r Power cable and plug damage
t Condition of refrigerant piping fasteners.
y Condition of each sensor installation
u Loose mounting sections
Bolts and nuts
-----
Casing frame, compressor, fan motor control box and temperature recorder box
Cable glands
-----
Control box
i Conditions of control box cover packing (water-proof) and temperature recorder box cover packing
(water-proof)
o Magnetic contactor contact point for burning out.
(2) Inspection before unit operation
q Gas leakage inspection
w Power voltage inspection (Automatic PTI range)
(3) Starting inspection and operation inspection of safety device and control equipment
q Starting Inspection whether the starting procedure is proper or not
Inspection for abnormal noise and abnormal vibration
Moisture in the refrigerant ----- This is reinspected at the end of PTI.
Rotating direction of fan motor.
w Safety device HPS ----- Measurement of the actuating pressure by stopping the condenser
fan motor.
e Control equipment Solenoid valve ----- Inspection of operation (open and close) and leakage
EFM ----- Speed switchover and rotating direction
EV, SMV
----- Inspection of operation (open and close) and leakage
(4) Operation in each mode
q Pull-down / 0˚C Pull-down time, voltage and current
w Chilled control 0˚C
Electronic temperature
Return, supply air temperature differential, voltage and current
recorder calibration
e Defrosting Defrosting time
r Pull-down / –18˚C
Pull-down time, evaporator fan motor speed switchover
t Frozen control –18˚C
Electronic temperature
(Temperature differential and rotating direction)
recorder calibration ON/OFF, voltage and current
Remained frost inspection
(5) PTI report preparation