Thermo King 914 724, Руководство пользователя

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Unit Description
The Thermo King CBci truck refrigeration system is a
three-piece system consisting of a condenser, an evaporator,
and a compressor. The assemblies are separate, and the con-
denser section can be installed either in a nosemount or an
undermount position. The evaporator mounts on the inside
of the front wall of the truck body close to the ceiling. The
compressor is mounted on and driven by the truck engine.
Refrigeration hoses or lines are used to connect the con-
denser, the evaporator and the compressor. Model 20 units
have another compressor and an electric motor mounted in
the condenser section for electric standby operation.
The units are designed for low and medium temperature
applications on medium-sized trucks. There are two basic
models:
• Model 10: Cool and defrost on engine-driven compres-
sor operation.
• Model 20: Cool and defrost on both truck engine-
driven and electric standby compressor operation.
The control circuits operate on 12 or 24 Vdc supplied by the
truck batteries for over-the-road operation. On standby
operation, the power is rectified from an AC transformer.
The refrigeration system is protected by a high pressure cut-
out switch and a low pressure cutout switch.
The remote control box is normally mounted on the truck
body. It contains the On-Off switch, manual defrost switch,
thermometer, thermostat, and indicator lights. The remote
control box cover must be opened to access the thermostat.
An optional cab control box is available. It is mounted in the
truck cab and replaces the remote control box. The cab con-
trol box contains the On-Off switch, Manual Defrost switch,
thermometer, thermostat, and indicator lights. The Model 20
cab control box also has a warning light that illuminates if
the driver starts the truck engine while the electric standby
cord is still plugged into the power receptacle.
The electric standby compressor is connected in parallel
with the engine-driven compressor on the Model 20 units.
The engine compressor is driven by a belt from the engine.
The standby compressor is mounted in the condenser sec-
tion and is belt driven by an electric motor. Both compres-
sors use the same refrigeration system circuit. Check valves
isolate one compressor from the other during operation.
Compressor operation is controlled by the thermostat, start-
ing the motor on electric standby or energizing the clutch
during engine operation.
Selection of engine operation or standby operation is auto-
matic on Model 20 units. When the Model 20 unit is
plugged into standby power, engine operation is automati-
cally locked out. If the driver turns the truck on while the
power cord is still plugged into a power receptacle, the
power cord warning light (Model 20 only) comes on to
remind the driver to unplug the cord. The engine driven
compressor cannot be started until the power cord is
unplugged from the unit.
A three-way valve refrigeration system provides defrost in
the unit. An electronic defrost timer can initiate defrost
automatically. Defrost is normally terminated by the defrost
termination switch mounted on the evaporator coil, but the
defrost timer can also terminate defrost.
Liquid Injection System
If the discharge gas leaving the engine driven compressor
reaches a temperature of 230 ± 5 F (110 ± 3 C), the high
temperature switch closes, providing voltage to the liquid
injection solenoid. The solenoid opens a valve, allowing liq-
uid refrigerant to flow from the liquid line near the receiver
outlet valve to the metering orifice attached to the suction
fitting at the compressor. As the refrigerant passes through
the metering orifice it expands and evaporates, cooling the
suction gas entering the compressor. This cooling effect is
transferred to the discharge gas leaving the compressor from