Howard Shanks•9 Jan 2018

ADVICE

How to operate the Thermo King SB-30 Series fridge

The ins and outs of one of Thermo King's most popular fridge units laid bare…

In this article we explain the basic operation of Thermo King's SB-30 Series fridge, showing you how to start the unit and change the set-point temperature, along with how to read the engine hours in the control panel.

The Thermo King SB-30 series is arguably the most common refrigeration unit found on fridge vans throughout the country. A one-piece, self-contained, diesel-powered unit, it operated via a SMART REEFER 3 (SR-3) programmable microprocessor controller. The unit mounts on the front of the trailer with the evaporator extending through an opening in the front wall, which can then have optional ducting to direct airflow.

The unit features cooling and heating using a quiet running engine from the Thermo King TK486 engine family. The four-cylinder TK486V is in the Tier 2 family of engines and is a water-cooled, direct-injection diesel engine. It is designed to run at high speed (2600rpm) in the SB-330. The engine is coupled directly to the compressor on the Model 30. Belts transmit power to the unit fans, alternator and water pump.

The SB-230 and SB-330 are equipped with a Thermo King X430L reciprocating compressor with 30.0 cubic inch (492cc) displacement.

Electronic Throttling Valve

The Electronic Throttling Valve (ETV) is optional on the SB-230 and standard on the SB-330. The ETV provides enhanced control of the refrigeration system by:

• Allowing the refrigeration system to fully utilise the power capabilities of the engine under varying conditions

• Providing an additional measure of protection against high discharge pressures

• Protecting the engine from high coolant temperature shutdowns

• Providing a means of precise temperature control.

You can tell if the unit has an ETV by looking at the compressor. Units with an ETV have a suction valve adapter, whereas units without an ETV have a mechanical throttling valve.

Defrost cycle

Because frost gradually builds up on the evaporator coils as a result of normal operation, the unit uses hot refrigerant to defrost the evaporator coil. Hot refrigerant gas passes through the evaporator coil and melts the frost. The water flows through collection drain tubes onto the ground. The methods of defrost initiation can either be automatic or manual.

When Automatic Defrost is selected, the Base Controller automatically initiates timed or demand defrost cycles. The Base Controller can be programmed to initiate timed defrost cycles at intervals of two, four, six, eight, or 12 hours. Demand defrost cycles occur if the differences between the return air temperature, discharge air temperature, and coil temperature exceed certain limits. The unit can enter defrost cycles as often as every 30 minutes if required.

In Manual Defrost mode, the operator initiates a defrost cycle by depressing the manual defrost button.

Pre-trip inspection (before starting the unit)

Pre-trip inspections are an important part of any preventative maintenance program and designed to minimise operating problems and breakdowns. Thermo King suggests that operators perform the following pre-trip inspection before every trip involving refrigerated freight.

• Fuel: Make sure the diesel fuel supply is adequate to guarantee engine operation to the next checkpoint. Allow for maximum fuel consumption of five litres per hour of engine operation.

• Engine Oil: Check the engine oil level. It should be at the 'Full' mark when the dipstick is threaded all the way into the oil pan. Do not overfill.

• Engine Coolant: The engine coolant must have antifreeze protection to -30 F (-34 C). Add coolant if Alarm Code 37 is active. Check and add coolant to the expansion tank only.

• Battery: Make sure the battery terminals are tight and free of corrosion.

• Belts: Make sure belts are in good condition and adjusted to the proper tension.

• Electrical: Check the electrical connections to make sure they are securely fastened. Wires and terminals should be free of corrosion, cracks, and moisture.

• Structural: Visually inspect the unit for leaks, loose or broken parts, and other damage.

• Damper: Make sure the damper in the evaporator air outlets move freely, with no sticking or binding.

• Coils: Make sure the condenser and evaporator coils are clean and free of debris.

• Defrost Drains: Check the defrost drain hoses and fittings to make sure they are open.

Smart Reefer-3 functions

• No. 1: 'On Key'. This key is used to turn the unit on. First the display will briefly show the Thermo King Logo and then the statement, "Configuring System – Please Wait". When the power-up sequence is complete, the display shows the Standard Display of box temperature and set-point. The 'Diesel Engine Starting' Screen briefly appears as the engine preheats and starts. The Standard Display showing box temperature and set-point reappears when the unit is running.

• No. 2: 'Off Key'. This key is used to turn the unit off. First the display will briefly show "System is Powering Down – Please Wait". When the power-down sequence is complete, the display will be blank.

• No. 3: 'Standard Display'. The Standard Display is the default display. It appears if no other display function is selected. The Standard Display shows the box temperature and set-point.

>> Cooling arrow when pointing down, Heating when pointing up.

>> Current van temperature.

>> Temperature set-point.

• No. 4: 'Defrost Key'. Press this key to initiate a Manual Defrost cycle.

• No. 5: 'CYCLE SENTRY/Continuous Mode Key'. Press this key to switch back and forth between the CYCLE-SENTRY mode and the Continuous Run mode. If OptiSet Plus is in use, it may not be possible to change the Mode.

• No. 6: The four 'soft' keys under the display are multi-purpose keys. Their function changes depending on the operation being performed. If a soft key is active the key function is shown in the display directly above the key. The keys are numbered from left to right, with Key 1 on the far left and Key 4 on the far right.

Typical soft key applications:

• Set-point?

• Gauges?

• Sensors

• Menu

• Next/Back

• Yes/No

• +/–

• Select/Exit

• Clear/Help

• Hour meters

Starting the unit

To start the fridge unit press and hold the ON button until the Thermo King logo illuminates. (NB: The ON key must be held down until the Thermo King Logo appears. If the ON key is not held down long enough (approximately half a second), the display may flicker but the unit will not start up. If this occurs, hold the ON key down until the Thermo King logo appears. In extremely cold ambient temperatures it may take up to 15 seconds for the first display to appear.)

The 'Configuring System' screen briefly appears while communications are established and the unit prepares for operation.

The Standard Display showing box temperature and set-point briefly appears.

The 'Diesel Engine Starting' Screen briefly appears as the engine preheats and starts.

The Standard Display showing box temperature and set-point reappears when the unit is running.

Turning the unit off

To turn the machine off, press the 'OFF' key. The engine will immediately shut off. The "System is Powering Down" screen will briefly appear. The 'OFF' screen will briefly appear. The screen goes blank when the unit power is off. To start the unit again, press the 'ON' key.?

To change the set-point

While in the standard display press the 'SETPOINT' soft key on the bottom left. The 'Set-point' screen briefly appears, then the 'Current Set-point' screen appears.

Press the + or - soft keys to change the set-point reading.

Press the 'YES' key to confirm the new set-point temperature or 'NO' soft key to cancel the new set-point and return to the standard display with no change made.

When the 'YES' key is selected a screen confirming the new set point is momentarily displayed then the Standard display screen resumes.

Navigating the Main Menu to locate engine hours

Begin at the Standard Display.

Press the 'MENU' soft key.

Press 'NEXT' or 'BACK' soft keys to scroll up or down through the main menu areas to the Hourmeter menu.

Press the 'SELECT' soft key to enter the Hourmeters Menu.

Press the 'EXIT' soft key to return to the Standard Display.

How to operate the Thermo King SB-30 Series fridge

Tags