| Description and Operation CFC-free refrigeration systems are used in the Ford Transit Freshliner. The powerful systems have a modern hot gas defrost system and an adjustable temperature control system (0 to +12°C). Additional stationary refrigeration is optionally available. The passenger compartment does not have air conditioning. Refrigeration system In vehicles fitted with a refrigeration system, the compressor, condenser core, high-pressure cutoff switch and electrical wiring of conventional air conditioning systems have been adopted. However, an expansion valve is also used, in contrast to vehicles with air conditioning. The function of the accumulator/drier is assumed by a combination comprising a separate accumulator that is only used for the refrigeration system (in the engine compartment instead of the accumulator/drier) and a drier/filter (behind the driver's seat). The evaporator core is located above the loading space at the rear wall of the driver's cab and is equipped with four evaporator core fans. The refrigeration compartment temperature is set via a control panel located in the headliner instead of the front interior lamp. WARNING:Repairs to the 230-volt system may only be carried out by trained personnel. Failure to observe this instruction can lead to injury. WARNING:The stationary refrigeration system must not be connected to the 230-volt circuit during repair work. Failure to observe this instruction can lead to injury. Stationary refrigeration The stationary refrigeration system comprises the components of the refrigeration system as well as an additional compressor which is driven by a 230-volt motor via a drive belt, an additional accumulator, a power supply switch box and a power supply transformer. The compressors and the accumulators in the refrigeration system and stationary refrigeration are identical. To prevent manipulations by third parties, as well as to protect sensitive electrical components, these parts have been positioned in the driver's cab, behind the seats. During operation of stationary refrigeration, the vehicle voltage required for operating the evaporator core fans, the two radiator fans etc. is generated by the power supply transformer to prevent the vehicle battery from being drained. The system is connected to the 230-volt circuit via a special cable which is supplied with the system Hot gas defrost The condensation that forms and freezes when the loading space temperature drops, icing up the evaporator core, must be removed to retain the refrigerating capacity. This is achieved via the hot gas defrost. A differential pressure sensor located in the evaporator core case measures the air pressure upstream and downstream of the evaporator core. If required, hot, gaseous refrigerant is conveyed directly upstream of the evaporator core and mixes there with the cold, liquid refrigerant after the defrost valve Y2 has opened. The defrost operation is also initiated automatically every two hours by the electronic controller or manually. After the defrost procedure, the system continues to cool automatically. CAUTION:The water drain hoses must not be sealed off. The condensation is conducted away via two water drain hoses which are routed to the outside through the vehicle floor. As a result, puddles of water may form under the vehicle. Bypass If the suction pressure at the accumulator drops below 0.8 bar, the bypass is opened via the bypass valve Y3. This injects refrigerant downstream of the evaporator core via an orifice pipe in order to ensure adequate cooling and lubrication of the compressor in operation. Stationary refrigeration pressure regulator The adjustable pressure regulator protects the stationary refrigeration motor from overloading when starting up after relatively long downtimes or after the defrost period (high pressure in the evaporator core). It should only be adjusted during hot gas defrost (set pressure p=0.8 bar). Fault message An audible warning indicates a fault in the refrigeration system, which can also been seen from a flashing display of the current fault code. The refrigeration system switches off and the display continues to flash until the fault has been remedied. Refrigeration System Refrigerant Circuit | Item | Description | | 1 | Compressor | | 2 | Compressor temperature switch | | 3 | High-pressure cutoff switch 30 bar | | 4 | Condenser core | | 5 | Drier/filter | | 6 | High-pressure cutoff switch 28 bar | | 7 | Refrigeration valve Y1 | | 8 | Bypass valve Y3 | | 9 | Expansion valve | | 10 | Evaporator core | | 11 | Defrost valve Y2 | | 12 | Bypass control pressure switch | | 13 | Accumulator | | 14 | Low-pressure cutoff switch | | 15 | High pressure (gaseous and hot) | | 16 | High pressure (liquid and hot) | | 17 | Low pressure (liquid and cold) | | 18 | Low pressure (gaseous and cold) | Refrigerant Circuit - Refrigeration System with Stationary refrigeration | Item | Description | | 1 | Compressor | | 2 | Compressor temperature switch | | 3 | High-pressure cutoff switch 30 bar | | 4 | Condenser core | | 5 | Drier/filter | | 6 | High-pressure cutoff switch 28 bar | | 7 | Refrigeration valve Y1 | | 8 | Bypass valve Y3 | | 9 | Expansion valve | | 10 | Evaporator core | | 11 | Defrost valve Y2 | | 12 | Bypass control pressure switch | | 13 | Accumulator | | 14 | Low-pressure cutoff switch | | 15 | Stationary refrigeration pressure regulator | | 16 | Stationary refrigeration accumulator | | 17 | Stationary refrigeration compressor | | 18 | Stationary refrigeration non-return valve | | 19 | High pressure (gaseous and hot) | | 20 | High pressure (liquid and hot) | | 21 | Low pressure (liquid and cold) | | 22 | Low pressure (gaseous and cold) | Controller Status Display - Refrigeration System | Display | Description | | 1 | Compressor on/off | | 2 | Evaporator core fans on/off | | 3 | Refrigeration valve Y1 on/off | | 4 | Bypass valve Y3 on/off | | 5 | Hot gas defrost via differential pressure (defrost as needed) on/off | | 6 | Hot gas valve Y2 on/off | | 7 | Maximum high pressure exceeded (28 bar) | Controller Status Display - Refrigeration System with Stationary refrigeration | Display | Description | | 1 | Maximum high pressure exceeded (28 bar) | | 2 | Condenser core fan on/off | | 3 | Compressor on/off | | 4 | Refrigeration valve Y1 on/off | | 5 | Bypass valve Y3 on/off | | 6 | Evaporator core fans on/off | | 7 | Hot gas valve Y2 on/off | | 8 | Stationary refrigeration compressor on/off | | 9 | Hot gas defrost via differential pressure (defrost as required) on/off | Refrigeration System Sequence After switching on the refrigeration system by pressing the On/Off switch, the display will start flashing for the self-test. Then the actual loading space temperature is displayed and the refrigeration valve Y1 opens. The compressor switches on (with a time delay of 2 seconds for vehicles built after 11/2001) if the high pressure is below 28 bar and the compressor temperature is below 120°C. The evaporator core fans switch on if the evaporator core temperature is below 10°C. The bypass line to the compressor is opened via the bypass valve Y3 if the suction pressure at the accumulator in the engine compartment is below 0.8 bar. Hot gas defrost takes place via the defrost valve Y2 if the evaporator core is iced up. Hot gas defrost takes place in automatic mode after two hours of operation or via manual initialization. The compressor switches off via the powertrain control module (PCM) if the suction pressure is below 0.2 bar; there is no feedback to the refrigeration system control module. After the compressor has been switched on automatically, the controller checks the system pressure which must be above 2 bar. The compressor switches off if the compressor temperature is above 120°C and switches on again when the compressor temperature is below 115°C. The refrigeration system switches off if the high pressure is above 28 bar. Operation of the system can only be restarted by pressing the Reset button. For vehicles built from 11/2001, the refrigeration system switches off if the high pressure is above 28 bar and switches on again below 16 bar. After the 5th pressure peak above 28 bar, operation of the system can only be restarted by pressing the Reset button. The compressor switches off via the PCM if the high pressure at the compressor is above 30 bar. The compressor then switches on again automatically; there is no feedback to the refrigeration system control module. | 
