Thermo King SB-III 30 SR+, Manual

Page: 30 / 120

Operating Instructions (Rev. 04/02)
20
3. DATA INTERFACE. The Data Interface is a serial port
that can be used to connect the microprocessor to an
IBM
®
PC compatible computer.
4. 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.
5. COMPRESSOR OIL SIGHT GLASS. The compressor
oil sight glass is used to check the relative level of com-
pressor oil in the compressor sump.
6. 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 25 in. of water column.
Press the button on the top of the restriction indicator
after servicing the air filter. Replace the EMI 3000 air
cleaner element (see “EMI 3000 Air Cleaner” on page
52) at 3,000 hours or two years (whichever occurs first)
if air restriction indicator has not reached 25 in.
7. REMOTE STATUS LIGHT (Optional). The 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
near the battery. The fuse link is located in the positive
battery cable in late model units. 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.
A 40 amp fuse (F9—#2 Circuit) protects the 2AA cir-
cuit, which is the main power circuit.
A 15 amp fuse (F3—Damper) protects the 29F circuit,
which supplies power to the damper solenoid.
A 15 amp fuse (F18—High Speed Solenoid) protects
the 7D circuit, which supplies power to the high speed
solenoid.
A 15 amp fuse (F21—#8 Circuit) protects the 8F cir-
cuit, which supplies power to various control relays and
components.
A number of 2, 3, or 5 amp fuses protect microproces-
sor circuits, control relay circuits, remote status light
circuits (optional), and various components.
3. HIGH PRESSURE CUTOUT. The high pressure cutout
is a pressure sensitive switch that is located in the com-
pressor discharge manifold. If the discharge pressure
rises above 470 psi (3241 kPa), the switch opens the 8D
circuit to the fuel solenoid, which stops the engine.
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 a high pres-
sure line near the condenser. Its location is such that
when the pressure is expelled from the valve, it would
be directed away from anyone servicing the unit.