Thermo King SB-190 30, Manual

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Operating Instructions (Rev. 12/03)
25
UNIT INDICATORS
1. RECEIVER TANK SIGHT GLASS. The receiver
tank sight glass is used to check the amount of refriger-
ant in the system, and the moisture content of the
refrigerant.
2. COMPRESSOR OIL SIGHT GLASS. The compressor
oil sight glass is used to check the relative level of com-
pressor oil in the compressor sump.
3. AIR RESTRICTION INDICATOR. An air restriction
indicator is attached to the intake manifold. Visually
inspect the restriction indicator periodically to assure
the air filter is not restricted. Service the air filter when
the yellow diaphragm indicates 22 in. of water column.
Press the button on the top of the restriction indicator
after servicing the air filter.
4. REMOTE STATUS LIGHT (Optional). The optional
remote status light indicates the operating status of the
unit. The green “T” indicates the unit is functioning
properly. The amber “K” indicates the unit has a check
alarm but is still functioning. The green “T” and amber
“K” both flash to indicate the unit has a shutdown
alarm and is not functioning.
UNIT PROTECTION DEVICES
1. FUSE LINK (Current Limiter). The fuse link is located
in the positive battery cable. The fuse link protects the
electric system from a short in the 2 circuit.
2. FUSES. A number of fuses, located on the relay board,
protect various circuits and components.
Fuse F3 (15 amp) protects the circuit that provides
power to defrost relay and the damper.
Fuse F9 (40 amp) protects the main control power
circuit.
Fuse F18 (15 amp) protects the circuit that provides
power to the throttle solenoid.
Fuse F21 (25 amp) protects the circuit that provides
power to the On/Off switch.
A number of 2 and 5 amp fuses protect microprocessor
circuits, control relay circuits, remote light circuits and
various components.
3. HIGH PRESSURE CUTOUT. The high pressure cutout
is a pressure sensitive switch, which is located in the
compressor discharge service valve. The switch opens
to shut down the unit if the discharge pressure rises
above 470 psi (3241 kPa).
4. HIGH PRESSURE RELIEF VALVE. The high pres-
sure relief valve is designed to relieve excess pressure
within the refrigeration system. The valve is a spring-
loaded piston that lifts off its seat when refrigerant
pressure exceeds 500 psi (3447 kPa). The valve will
reseat when the pressure drops to 400 psi (2758 kPa).
The valve could possibly leak refrigerant after it has
relieved excess pressure. Tapping the valve lightly may
help the valve reseat and SEAL PROPERLY. The valve
is non-repairable and requires no adjustment. If the
valve fails to reseat properly, remove the refrigerant
charge and unscrew and replace the valve.
The high pressure relief valve is located on the receiver
tank. Its location is such that when the pressure is
expelled from the valve, it would be directed away
from anyone servicing the unit.
5. LOW OIL LEVEL SWITCH. The low oil level switch
closes if the oil drops below a certain level. If it stays
closed for a specified time, the microprocessor will shut
the unit down and record alarm code 66.
6. PREHEAT BUZZER. The preheat buzzer sounds when
the CYCLE-SENTRY system energizes the glow plugs
and when the unit is turned on (buzzer check). This
should warn anyone near the unit that the CYCLE-
SENTRY system is about to start the diesel engine.