Dismantling refrigeration equipment on MAN TGA trucks is a technically complex procedure that requires not only metalworking skills, but also strict adherence to safety regulations. Unlike household models, autonomous refrigeration units (AGC) in heavy trucks run on diesel fuel and have a complex system of fastenings, electrics and hydraulics. Improper removal can lead to body damage, refrigerant leakage or failure of expensive electronics.
Before starting work, you must clearly understand what kind of modification you are dealing with, since MAN TGA it was equipped with Thermo King, Carrier, Zanotti and other manufacturers, and their locations may vary. Most often we are talking about removing the compressor-condensing unit (CCU), which is located on the front wall of the body or on the roof. A critically important step is the complete pumping of the refrigerant (freon) into special receivers before any depressurization intervention, which is regulated by environmental standards and operating instructions.
The dismantling process takes from 3 to 6 hours, depending on access to the components and the condition of the fasteners. You will need not only a standard set of tools, but also specialized equipment to work with refrigeration circuit. Ignoring preparatory steps, such as de-energizing the system and draining technical fluids, can lead to a short circuit or chemical burns.
Preparation of the workplace and the necessary tools
Organization of the workspace is the foundation for successful dismantling. The truck must be installed on a level area with a hard surface to prevent the body from distorting when removing heavy components. Before proceeding disassembling the unitensure that you have clear access to the front of the body or roof where the refrigeration unit is located. To work at height, you will need a reliable stepladder or aerial platform that provides a stable platform.
The set of tools should be expanded compared to a standard plumbing kit. You will need spanners and open-end wrenches in sizes from 8 to 24 mm, since fasteners often have metric threads and can be over-tightened due to vibrations in transit. Also required are powerful screwdrivers, pliers, wire cutters and, possibly, an impact wrench for unscrewing stuck frame mounting bolts. MAN TGA often has metric threads and can be over-tightened due to vibrations in transit. Also required are powerful screwdrivers, pliers, wire cutters and, possibly, an impact wrench for unscrewing stuck frame mounting bolts.
Pay special attention to personal protective equipment and special tools. Working with refrigerants requires the use of safety glasses and gloves that are resistant to low temperatures and chemicals. To work with electricians, you need a multimeter to check the absence of voltage, and to work with tubes, a rolling tool and a pipe cutter if you plan to partially replace the lines.
☑️ Preparation for dismantling
It is important to prepare containers in advance for draining diesel fuel from the autonomous tank and oil from the compressor. Even a small amount of fuel spilled on the body can damage the paintwork or rubber seals, so the presence of rags and absorbent is mandatory.
Disconnecting the power supply and fuel system
The first step in the safe dismantling algorithm is to completely de-energize the system. In trucks MAN TGA the refrigeration unit is usually powered from a separate battery or through the main disconnect switch. Find the fuse box responsible for the AGC and remove them. After this, it is necessary to disconnect the terminals directly from the battery to eliminate the risk of a short circuit if the wire insulation is accidentally damaged during operation.
The next step is working with the fuel system. Autonomous refrigerator consumes diesel directly from the truck's tank or has its own small tank. You need to turn off the fuel valve, if provided by the design, or carefully disconnect the fuel hose from the unit injector pump. Place a prepared container under the disconnection point, as pressurized fuel may remain in the pipes.
⚠️ Attention: Before disconnecting any fuel hoses, make sure that the truck engine and refrigeration unit are completely cool. Contact of hot fuel with skin or hot engine parts may cause fire or burns.
After physically disconnecting the hoses, plug the holes with plugs or a clean rag to prevent dust and dirt from entering the fuel system. Electrical connectors that go to the control unit (controller) should be disconnected after first remembering or photographing their location. Often the connectors have locking latches that must be carefully pressed out so as not to break the plastic.
Draining the refrigerant and oil from the compressor
The most critical technical stage is working with the refrigeration circuit. According to environmental standards, the release of freon into the atmosphere is prohibited. To remove it, a pressure gauge station with a vacuum pump and a receiver for collecting gas is used. Connect the station hoses to the high and low pressure service ports on the unit.
The pumping process takes from 15 to 30 minutes. At this time, you can carry out a visual inspection of the condition of the tubes and heat exchanger. If you plan to dispose of an old unit, the gas can be pumped into a cylinder, but if the equipment is to be reinstalled, the purity of the refrigerant must be high. After pumping out the gas, it is necessary to drain the compressor oil, which circulates in the system along with freon.
To drain the oil, it is often necessary to remove the compressor itself or use a drain plug, if provided by the design Thermo King or Carrier. The oil can be hot and corrosive, so use a heat-resistant container. The volume of oil depends on the compressor model, usually from 0.5 to 1.5 liters.
| Refrigerant type | Pressure at 25°C (Bar) | Oil type | Recycling features |
|---|---|---|---|
| R134a | 6.5 | PAG / POE | Requires collection into the receiver |
| R404A | 10.2 | POE | High pressure, caution |
| R452A | 11.5 | POE | Modern analogue, toxic |
| R12 (old models) | 5.8 | Mineral | Prohibited, only recycling |
What will happen if the oil is not drained?
If the oil is not drained before dismantling the compressor, it will spill throughout the body, damage the insulation and create a fire hazard. In addition, loss of oil will require a complex procedure for filling and evacuating the system during assembly.
Dismantling the compressor-condensing unit
After all communications are disconnected and the liquids are removed, it is the turn of mechanical removal of the unit. The compressor-condensing unit (CCU) is MAN TGA usually attached to the front panel of the body with powerful bolts or welded brackets. The weight of such a unit can reach 100-150 kg, so it is absolutely impossible to remove it alone.
Use a winch, a beam crane, or the help of two or three assistants. Before unscrewing the mounting bolts, it is recommended to secure the unit with safety straps. Unscrew the fastening bolts evenly, checking to see if there are hidden fasteners or additional spacers left somewhere. There are often situations where the lower bolts are corroded and require penetrating oil (WD-40) and heat to loosen.
When removing the block, keep an eye out for residual tubes and wires that may have been forgotten or poorly secured. A sharp jerk of a heavy unit can damage the front wall of the body or break off the remaining wiring, which will complicate further repairs. Smoothly lower the block onto prepared wooden blocks or rubber mats so as not to damage the fins of the condenser.
- 🔧 Check the condition of the rubber vibration mounts - when installing a new block, it is better to replace them.
- 🔧 Inspect the mounting points for corrosion and, if necessary, clean the metal.
- 🔧 Make sure that the thermal insulation of the body (sandwich panels) is not damaged during removal.
- 🔧 Save all dismantled bolts and washers in a separate marked container.
Removing the evaporator and internal components
If the task is to remove the refrigerator completely, including the inside, then you need to dismantle evaporator unit, which is located inside the body. It is usually accessed through a hatch in the front wall or by partially dismantling the inner lining. In models MAN TGA with an all-metal body, this may require careful drilling of rivets.
The internal unit is attached to the ceiling or front wall. Before removal, make sure that the condensate drainage system is disconnected. Often the drainage pipes run through the entire body and must be carefully pulled out without damaging the insulation. The electrical connector of the evaporator fan must also be disconnected.
⚠️ Attention: When dismantling the indoor unit, be careful with the aluminum fins of the evaporator. They are very soft and easily wrinkle, which in the future will lead to impaired air circulation and a decrease in cooling efficiency.
After removing the internal components, inspect the passage holes in the body. They must be temporarily sealed if the truck is to be used without a refrigerator to prevent moisture and drafts. To do this, you can use plywood plugs with a gasket made of insulation.
Packaging and transportation of dismantled equipment
Proper packaging of the removed equipment is the key to the fact that it will reach its destination in working condition. The condensing unit has many protruding parts that are easily damaged during transportation. It is recommended to wrap the unit with stretch film in several layers, after closing the open ports and holes with plugs.
The unit should only be transported in a vertical position. An inclination of more than 45 degrees or an upside down position may result in residual oil leaking from the compressor into the circuit, which will cause water hammer during the first start-up. Secure the unit in the vehicle body so as to prevent its movement and vibration.
If the removed refrigerator is planned to be stored for a long time, treat the metal surfaces with an anti-corrosion compound. Pay special attention to pipe cuts and threaded connections. It is best to store electronic control units in a dry place at room temperature, packed in a plastic bag with silica gel.
Frequently asked questions (FAQ)
Is it possible to remove a refrigerator on a MAN TGA without pumping out freon?
Technically, it is possible to simply cut through the pipes, but this is illegal and dangerous. The release of freon into the atmosphere is prohibited by environmental legislation in most countries. In addition, a sudden release of gas under pressure can carry oil particles with it and cause frostbite on your hands. Always use a pressure gauge station.
Is it necessary to change the oil in the compressor after dismantling?
If the dismantling was carried out normally and no moisture or air entered the system, it is not necessary to change the oil if its level and color are normal. However, if the compressor has been sitting idle for a long time or dust has entered the system, a complete replacement of the oil and filter-drier must be carried out.
How much does a standard unit weigh on a MAN TGA?
The weight of the compressor-condensing unit varies from 80 to 160 kg depending on the model (T-800, T-1000 and etc.) and manufacturer. The internal evaporation unit weighs significantly less, usually 20-40 kg, but has large dimensions.
What to do with the holes in the body after removal?
The holes must be welded or closed with special sealed plugs (plasters), restoring the sandwich structure of the wall. Simply covering it with a rag or foam is not enough - this will break the thermal insulation and lead to the formation of condensation and corrosion inside the body wall.