The process of removing a refrigeration unit or refrigeration unit mounted on the chassis of brand cars Scaniais a complex one an engineering task that requires strict adherence to safety regulations and specific design knowledge. Unlike their consumer counterparts, commercial cooling systems are integrated into the body or frame of the vehicle, which means additional fasteners, complex electrical circuits and hydraulic connections. Any careless movement can lead to damage to expensive components or injury to personnel.
Before starting any work, it is necessary to understand that the term “pull out” can mean either dismantling the compressor-condensing unit (CCU) for replacement, or completely removing the refrigeration box from the truck frame. In both cases, the key success factor is proper preparation of the workplace and the availability of specialized equipment. Ignoring the preparatory stage often causes distortions, ruptures of tubes and deformation of seats.
In this article we will analyze in detail the algorithm of actions necessary for safe work. We will pay special attention to the nuances of working with refrigerants, features of fastening systems Scania and methods of lifting heavy components. It is important to consider that modern climate control systems and refrigeration equipment are full of electronics that are sensitive to static discharge and mechanical shock.
Preparation of the workplace and the necessary tools
The first step in the dismantling process is to organize a safe space around the vehicle. The truck must be on a flat, solid platform that prevents spontaneous movement. The use of wheel chocks is a mandatory requirement and should not be ignored. It is also necessary to ensure sufficient lighting of the work area, since many fasteners are located in hard-to-reach and darkened places.
To perform the task efficiently, you will need a specific set of tools, without which there is no point in starting work. A standard set of keys will not be enough here, since fasteners in commercial vehicles often have increased strength and specific dimensions. Particular attention should be paid to the condition of the tool: torn edges of the bolts can turn simple dismantling into a multi-hour problem.
- 🔧 A set of socket heads with extensions and large diameter wrenches (up to 24 mm and above).
- 🔋 Multimeter and tester for checking the absence of voltage before disconnecting the terminals.
- 🧤 Protective gloves, glasses and specialized shoes with a metal toe.
- 🏗️ Lifting equipment (beam crane, hoist or forklift) with a lifting capacity of at least 500 kg.
The issue of refrigerant collection deserves special attention. If freon remains in the system, it is strictly forbidden to release it into the atmosphere. For this purpose, a Yiwu freon filling station is used, which allows you to vacuum the system before unwinding the pipelines. This is not only an environmental requirement, but also a condition for maintaining the operability of the compressor during subsequent installation.
⚠️ Attention: Before starting work, be sure to make sure that the pressure in the cooling circuits has been relieved to atmospheric pressure. Residual pressure can cause oil and refrigerant to escape under high pressure, causing chemical burns and frostbite.
Check that all necessary consumables are available in advance. During the dismantling process, it often turns out that some gaskets, clamps or O-rings are disposable and require replacement. Using old seals during reassembly can lead to leaks and repeated costly repairs.
Removal of external panels and access to the unit
Access to the main components of the refrigeration unit on trucks Scania is often hidden behind decorative and protective panels. These elements can be mounted either with bolts or with quick-release latches. You need to act carefully so as not to damage the plastic fasteners, which become especially fragile in the cold. If work is carried out in winter, it is recommended to pre-heat the plastic elements with warm air.
The process of removing panels requires consistency. First, the upper cladding elements are removed, then the side ones, and only after that access to the load-bearing frame is opened. In some refrigerator models, access to the compressor is possible only after partial dismantling of the front wall of the booth or removal of spoilers. Visual inspection at this stage it helps to identify hidden damage to wiring or pipelines that may not have been visible before.
Secrets of fastening Scania panels
On some Scania truck models, panels can be secured with hidden bolts under rubber plugs or logos. Carefully inspect the surface for the presence of such elements so as not to break the plastic when trying to remove it by force.
When removing electrical connectors, you must use a special puller or carefully press the latches. Pulling the wires is prohibited - this leads to oxidation of the contacts or breakage of the wires inside the insulation. It is recommended to mark or photograph all disconnected connectors so as not to confuse their purpose during assembly.
Pay special attention to the condition of the wire insulation. On high-mileage trucks, the insulation often loses its elasticity and cracks. When removing wiring harnesses, try to minimize bending and stress. If you notice damaged insulation, it is better to immediately isolate the defect location to avoid a short circuit during the first start-up after repair.
Disconnection of electrical and hydraulic systems
The power supply system of a refrigerator base Scania can be quite complex, including additional batteries, inverters and control units. The first step should always be to completely de-energize the system. To do this, the vehicle's mass switch is turned to the "off" position, and the terminals directly on the refrigeration unit are disconnected.
Hydraulic connections require a special approach. Before unscrewing the hydraulic hoses, make sure that the pressure in the hydraulic system has been relieved. To do this, the truck engine must be turned off and the hydraulic valve levers must be moved from position to position several times. It is necessary to place containers under the connections to collect residual hydraulic oil to avoid contamination of the work site.
- 🛑 Plug all open hydraulic holes with clean plugs immediately after disconnecting.
- 💧 Use lint-free rags to wipe the connections.
- 🔍 Check the condition of the hydraulic hoses for cracks and abrasions.
The electrical circuit of a refrigerator is often tied to the on-board network of the truck. When disconnecting, it is important not to damage the vehicle's standard wiring. Circuit break points must be reliably insulated. If dismantling involves long-term storage of the unit, then it is better to additionally treat the removed wires with preservative grease for contacts.
Modern control systems Scania often use a CAN bus. When working with electronics, it is important to avoid static electricity. Before touching electronic control units (ECUs), it is recommended that you touch a grounded metal part of the body to remove static charge. Damage to electronics by static may not be immediately noticeable, but will lead to unstable operation of the system in the future.
Technology for removing the compressor-condensing unit
The compressor-condensing unit (CCU) is the heart of the refrigeration unit and its heaviest element. Its weight can reach several hundred kilograms, so manual dismantling is impossible. A crane or hoist is used for lifting. It is important to correctly calculate the center of gravity of the block so that when lifting it does not tilt and damage neighboring components.
The KKB is attached to the frame or body through special shock-absorbing supports. These supports dampen vibrations of the operating compressor. When dismantling, you must first loosen, but not completely unscrew, the fastening bolts, then bring in the lifting mechanism slings and create a slight tension. Only after making sure that the load is hanging on the hook can you completely unscrew the fastening bolts.
| Type of fastening | Tool | Dismantling nuances | Risks |
|---|---|---|---|
| Threaded rods | Two nuts, a key | The locknut may stick | Thread breakage |
| Welded brackets | Glinder (if replacement) | Requires metal cutting | Damage to the frame |
| Quick-clamping paws | Manual key | Requires access from all sides | Breakage of the latch |
When lifting the block, it is necessary to control the position copper pipelines. They should not stretch or break. If the pipelines interfere with lifting, they should be carefully bent or the sections that interfere with extraction should be temporarily dismantled. Copper is a soft metal, and deformation of the tube can lead to its destruction due to vibration in the future.
☑️ Safe lifting of the KKB
After the unit is removed, it must be installed on a flat surface to prevent dirt and moisture from entering the open ports of the compressor. If the unit is planned to be stored for a long time, the ports must be immediately sealed with plugs. Moisture getting inside the compressor is a guaranteed breakdown the next time it starts.
Removing the evaporation unit and air ducts
The evaporation unit is usually located inside the refrigerator body or under its ceiling. Access to it is often limited, making work difficult. Before dismantling begins, it is necessary to remove the internal cladding of the ceiling or walls. In some designs Scania the evaporator is attached to the power frame of the booth, and its removal requires partial disassembly of the internal structure.
An important step is to disconnect the drainage system. During operation, condensate forms on the evaporator, which is discharged through the drainage pipes to the outside. These tubes often become clogged with dirt or frozen. When dismantling, they must be carefully cleaned or replaced, since clogged drainage will lead to water entering the load during future operation.
Air ducts that distribute cold air can be made of plastic or soft materials. They must be removed carefully so as not to tear. Damage to the air ducts will disrupt air circulation, which will lead to the formation of “warm zones” in the body and damage to the cargo. When removing, record the condition of each element in order to restore the original air flow configuration during reassembly.
⚠️ Attention: There may be refrigerant and compressor oil residues inside the evaporator unit. When dismantling, keep the unit upright to prevent oil from leaking into the heat exchanger, where it is difficult to remove.
If the evaporator unit is equipped with electric defrost heaters, check their integrity before reinstalling. Often during dismantling, fragile nichrome threads or their insulation are damaged. Checking the resistance of the heaters with a multimeter will take a couple of minutes, but will save you from a defrosting system not working in the future.
Common mistakes and precautions
One of the most common mistakes is an attempt to save time and not drain the oil from the compressor before transportation. Residual oil may mix with the refrigerant or leak, polluting the environment and creating a slippery surface. In addition, oil getting on rubber seals during storage can lead to their destruction.
Another mistake is using the wrong lubricant for threaded connections. During assembly, do not use lubricants that are incompatible with refrigerants and system materials (for example, some types of lithium may react with freon). Use only specialized lubricants recommended by the equipment manufacturer.
- ❌ Do not use an open flame to warm frozen components.
- ❌ Do not leave open system circuits without plugs, even for a short time.
- ❌ Do not ignore the markings of removed parts, relying on memory.
When working with heavy elements, workers’ backs often suffer. The use of mechanical aids - hoists, jacks, stands - should be a priority. Human error and fatigue can lead to a load falling, which will cause not only material damage, but also serious injuries.