| Description and Operation The air conditioning system on the Transit is equipped with an evaporator unit at the front and, in some cases, with an additional evaporator unit at the rear. The front circuit is largely identical on both variants and, if applicable, also supplies the rear evaporator unit with refrigerant. R134a refrigerant is used. To achieve the maximum cooling capacity, the air conditioning systems are equipped with a coolant shut‐off valve and a movable deflector in the air distribution housing. Front refrigerant circuit | 1 | Condenser | | 2 | Compressor | | 3 | High‐pressure switch | | 4 | Fixed orifice tube | | 5 | Evaporator | | 6 | Accumulator/dehydrator | | 7 | Low‐pressure switch | The compressor (2), driven by the engine, sucks the gaseous refrigerant out of the accumulator/dehydrator (6) and compresses it. The refrigerant gets hot and is passed into the condenser (1) under high pressure. Here, heat is extracted from the refrigerant by means of the forced air current flowing around the cooling ribs. As it loses heat, the refrigerant condenses and leaves the condenser. A fixed orifice tube (4), which separates the high‐pressure and low‐pressure side of the refrigerant circuit, is located between the condenser and the evaporator (5). This fixed orifice tube considerably slows down the flow of refrigerant from the compressor so that pressure builds up in the condenser and the liquid refrigerant expands in the part of the circuit leading to the evaporator after flowing through the orifice tube. In the evaporator, because of the transition of the refrigerant from the liquid to gaseous state, heat is extracted from the incoming fresh air. This cools the air, and any moisture contained in the air condenses in the evaporator. The refrigerant flowing out of the evaporator enters the accumulator/dehydrator and is again sucked into the compressor. To prevent damage caused by excessively high pressure (e.g. overfilling), the system is regulated by a high‐pressure switch (3). If the maximum permitted pressure is exceeded, the high‐pressure switch switches off the compressor. The working cycles of the compressor are regulated by the low‐pressure switch (7) according to the low pressure in the accumulator/dehydrator. The low‐pressure switch switches off the compressor permanently if the pressure is below the permitted limit (e.g. in the event of a leak). Rear refrigerant circuit | 1 | Fixed orifice tube | | 2 | Evaporator | | 3 | Expansion valve | | 4 | Accumulator/dehydrator | The refrigerant required for the rear circuit is taken from the front circuit in front of the fixed orifice tube (1) in liquid form and passed to the expansion valve (3) of the rear circuit. The expansion valve regulates the amount of liquid refrigerant passed to the evaporator (2) according to the pressure and temperature in the evaporator. The refrigerant leaves the evaporator in gaseous form and is returned to the front circuit via the accumulator/dehydrator (4). Rear evaporator/blower assembly | 1 | Air pipe with nozzles | | 2 | Air pipe | | 3 | Evaporator/blower assembly | | 4 | Cover | | 5 | Expansion valve | In some countries, the Transit is available with a rear evaporator/blower assembly. In this case, both evaporators are supplied from the same compressor. Coolant shut‐off valve | 1 | Solenoid valve for coolant shut‐off valve | | 2 | Coolant shut‐off valve | The temperature in the air distribution housing is controlled by mixing heated with unheated air. Therefore, air constantly flows through the heater radiator. However, if the temperature control is set to the furthest ”cold" setting, the maximum cooling switch in the control unit is activated. The maximum cooling switch opens the solenoid valve for the coolant shut‐off valve (1), thereby transmitting a vacuum to the diaphragm of the coolant shut‐off valve (2). The coolant shut‐off valve closes the inlet to the heater radiator. In addition, the control motor of the deflector in the air distribution housing is activated and the air current thereby directed past the heater radiator. System Overview, Transit Refrigerated Van | 1 | Direction of flow | | 2 | Accumulator/dehydrator | | 3 | Additional accumulator (if present) | | 4 | High‐pressure switch | | 5 | Compressor | | 6 | Condenser | | 7 | Evaporator | | 8 | Expansion valve | The Transit refrigerated van is based on the conventional Transit delivery van with air conditioning system. The surrounding insulation of the refrigerated compartment consists of a material with a particularly high insulation value. The interior trim panels are made of a lined, shock resistant plastic. |  | CAUTION: The polyurethane hard foam insulation of the vehicle is highly inflammable. For this reason a large area of the high‐resistance foam insulation must be removed before carrying out repair work to the refrigerated compartment involving welding in the area behind the passenger compartment. | The main features of the Transit refrigerated van are: - There is no air conditioning in the passenger compartment.
- The refrigeration system accumulator/dryer has been moved behind the driver's seat. Vehicles built after 01.01.1998 have an additional accumulator below the vehicle.
- On vehicles with a short wheel base the evaporator has one fan motor; on vehicles with a long wheel base it has two fan motors.
- The temperature in the refrigerated area is adjusted by means of an additional control in the instrument panel.
- The complete load area is heat insulated to approx. 50 mm.
- The load area floor is formed from watertight, slip‐proof and steam jet‐resistant aluminium.
|  | NOTE: National safety regulations. | In the UK, technicians working on air conditioning systems should comply with the guidelines issued by their local Health and Safety Executive. | | NOTE: Even when the air conditioning system has been drained, pressure can build up again from traces of refrigerant in the refrigerant oil if the system is closed. | - It is essential to follow the instructions provided by the refrigerant and equipment manufacturers when filling and evacuating the air conditioning system.
R134a refrigerant is known as a safe refrigerant, however accidents can occur if it is handled incorrectly. The following rules must therefore be observed: |  | WARNING: Risk of explosion. Soldering and welding work on a filled air conditioning system is not permitted. | - When handling refrigerant, it is essential to wear protective goggles and gloves, e.g. made of fluoroelastomer. Leather or fabric gloves are not suitable.
- Avoid contact with liquid R134a refrigerant. R134a evaporates at approx. ‐26°C at atmospheric pressure and causes frostbite. If liquid refrigerant comes into contact with the skin or eyes, wash the affected areas immediately with water. Seek medical assistance without delay.
- R134a must not be allowed to escape in confined spaces. Although R134a is not toxic, there is a risk of suffocation, as gaseous refrigerant is heavier than air.
- It is essential to avoid working with a naked flame on the air conditioning system as the highly toxic gases fluorophosgene and hydrogen fluoride are formed when the refrigerant is exposed to high temperatures.
- The maximum temperature of 70°C in the paint oven (measured under the hood) must not be exceeded.
- Never mix R134a refrigerant with R12 refrigerant.
- Never mix the refrigerant oils for air conditioning systems using R134a and R12 refrigerant.
- In addition, it is important to ensure that R134a is always extracted from the system and collected using one of the recommended servicing units. Releasing refrigerant into the atmosphere must be avoided at all costs for environmental reasons (greenhouse effect).
| | NOTE: When handling filling bottles, it is essential to take the following precautions: | - Protect from heat and frost.
- Transport upright.
- Do not drop.
- Always seal properly.
Filling bottles with one valve To extract liquid refrigerant, turn the bottle upside down, i.e. with the filling valve downwards. Filling bottles with two valves Do not turn the filling bottle upside down. Inhalation: | | WARNING: If the breathing has stopped or is irregular, give artificial respiration. In the event of cardiac arrest, perform heart massage. Call a doctor immediately. | Take the patient into the fresh air, keep him warm and let him rest. If necessary, give oxygen. Skin contact Rinse the affected part of the body with plenty of water. Eye contact Rinse eyes with plenty of water for at least 15 minutes. Consult a doctor. General Requirements | | NOTE: Filling or topping up with R12 refrigerant is no longer permitted. The systems concerned must be converted during servicing to take R134a. | One of the most important requirements when filling the air conditioning system is to use clean refrigerant. Any foreign matter ‐ including air, moisture and dirt ‐ in the air conditioning circuit will affect the temperatures and pressures in the air conditioning system. This will impair the operation of the air conditioning system. Furthermore, this foreign matter may lead to faults such as compressor failure due to excessive wear. Precautions | | NOTE: Air inside the circuit damages the system as it contains moisture and dirt and thus reduces the cooling capacity. The lines and connections of the air conditioning system must therefore always be sealed immediately. | | | NOTE: If the vehicle is more than 2‐3 years old or has high mileage, then the accumulator/drier must be renewed when changing main components such as the compressor, condenser, evaporator or refrigerant lines. The accumulator/drier must also be renewed if the system was opened for more than two hours or if metallic abraded particles are present in the coolant following damage to the compressor. | - Make sure that tools, measuring equipment and replacement parts are clean and dry.
- Before disconnecting refrigerant hoses, all connections and unions must be cleaned of dirt, water, oil etc. to prevent contamination of the system. All open connections should then be sealed immediately with suitable caps or plugs to prevent dust and moisture from entering.
- When unions are undone, O‐rings must always be renewed and lubricated with refrigerant oil prior to installation.
- All equipment and tools required should be kept within reach in order to avoid leaving the system open for longer than necessary.
- When topping up the refrigerant oil, ensure that the filling equipment (hose, reservoir) is clean and dry. The oil container should be sealed immediately after use.
- To ensure the system functions properly after refilling from new, the system must be evacuated (sucked dry) for approx. 30 minutes before refilling. This will ensure that any moisture in the system is evaporated and removed.
- If the system was open for an extended period (more than two hours), then the evacuation time must be increased to 2‐3 hours.
- After repair work has been carried out, all unions that were undone must be tested with a leak tester.
| Servicing unit | Combined | A'Gramkow | RHS3000/R134a | | Servicing unit | Combined | A'Gramkow | RHS650/R134a | | Servicing unit | Combined | A'Gramkow | RHS850/R134a | | Servicing unit | Recovery unit | Bear (Robinair) | 40‐410 (10324*) | | Servicing unit | Evacuation and filling unit | Bear (Robinair) | 40‐415 (17454*) | | Servicing unit | Combined | Bear (Robinair) | 40‐470 (17734*) | | Servicing unit | Combined | ICF | "Cleaner" R134a | | Servicing unit | Combined | Fischer (Germany only) | FAST ‐ 2000X | | Proprietary electronic leak tester (R134a) | | | | * Order codes for Robinair The oil must always be kept in a closed, sealed container to prevent moisture from entering. | | NOTE: If more than one component of the air conditioning system is being renewed, the total quantity of oil required is the sum of the individual quantities. However, the total fill capacity (for filling from new) must not be exceeded. | | | NOTE: If the new compressor is supplied without a compressor clutch and without refrigerant oil, renew the compressor clutch as described in Operation 34 628 0 in this section and top up the compressor with refrigerant oil as outlined in the description supplied. | | | NOTE: The air conditioning system needs fully topping up with refrigerant oil after it has been flushed. All of the oil is flushed out during the flushing process. Check to see whether new spare parts contain refrigerant oil. Do not use more than the maximum specified quantity. Refer to "General Specifications" for further information. | | | NOTE: After renewing a component, run the engine at idle speed for approx. five minutes with the air conditioning system switched on to distribute the refrigerant oil evenly. | | Compressor, with the oil quantity taken from the old compressor less than 90 ml | Top up 90 ml. | | Compressor, with the oil quantity taken from the old compressor between 90 ml and 150 ml | Top up with the oil quantity taken from the old compressor + 30 ml. | | Compressor, with the oil quantity taken from the old compressor greater than 150 ml | Top up 150 ml. | | Evaporator | Pour 90 ml into the new evaporator. | | Rear evaporator | Pour 50 ml into the new evaporator. | | Refrigeration system evaporator | Pour 40 ml into the new refrigeration system evaporator. | | Condenser | Pour 30 ml into the new evaporator. | | Refrigeration system condenser | Pour 20 ml into the new refrigeration system evaporator. | | Accumulator/dehydrator | Pour the oil from the old accumulator/drier into a clean measuring cylinder. Pour the same amount as that drained from the old accumulator/drier, plus 90 ml of new oil, into the new accumulator/drier. | | Refrigeration system accumulator/dehydrator | Measure by emptying the old accumulator/dehydrator. | | Refrigeration system accumulator (if present) | Initial fill: 50 ml. Exchange: Measure by emptying the old accumulator. | | Refrigerant line (with front air conditioning system) | Pour 30 ml into the line. | | Refrigerant line (with front and rear air conditioning system) | Pour 50 ml into the line. | | Expansion valve | No correction required | | Refrigeration system expansion valve | No correction required | | | NOTE: Faults such as burst hoses cause a sudden escape of refrigerant. In such cases, 60 ml of refrigerant oil to the correct specification must be added. | The protective caps on the new components are to prevent moisture and dirt from entering. The protective caps must therefore be left on the components as long as possible and should only be removed immediately prior to installation. Once the repair work is finished, check the air conditioning, evacuate the system and then fill it with R134a. Air conditioning leak test After filling the air conditioning system, the following connections must be checked with a leak tester: 3 connections on the accumulator/dehydrator 2 connections on the front air conditioning evaporator 2 connections on the rear air conditioning evaporator 1 connection on the air conditioning compressor 2 connections on the air conditioning condenser 2 filling valves 2 quick‐release couplings (front air conditioning) 6 quick‐release couplings (front and rear air conditioning) For refrigerated van only: 3 connections on the accumulator/dehydrator Two connections to the refrigeration system evaporator Two connections to the refrigeration system condenser If leaks are found, drain the air conditioning system. When doing this, use one of the recommended servicing units. Renew the leaking or faulty part. If necessary correct the quantity of oil as shown in the table on the previous page. Cooling power test With the refrigeration system switched on, measure the air temperature at the intake and outlet of the evaporator. - The temperature difference between the air intake and the air outlet should be approx. 8°C on short wheel base vehicles and approx. 5°C on long wheel base vehicles.
- With the doors shut, the temperature at the evaporator outlet three minutes after switching on the refrigeration system should be no higher than 10°C.
| 
