Air Conditioning
AIR CONDITIONINGThe A/C refrigerant system is a clutch cycling orifice tube type. The system components include the following:
- A/C compressor
- A/C clutch disc and hub
- A/C clutch field coil
- A/C condenser core
- A/C evaporator core
- A/C suction accumulator
- connecting refrigerant lines
The refrigeration system operation is controlled by the following:
- A/C evaporator core orifice
- evaporator air discharge temperature sensor
- A/C compressor pressure relief valve
- A/C pressure sensor
- low-charge protection switch
The refrigerant system incorporates an A/C compressor controlled by an evaporator air discharge temperature sensor.
The evaporator air discharge temperature sensor senses the A/C evaporator core air discharge temperature to control A/C compressor operation.
An A/C compressor pressure relief valve is installed in the A/C manifold and tube to protect the refrigerant system against excessively high refrigerant pressures.
The A/C evaporator core orifice is installed in the evaporator inlet tube to meter the liquid refrigerant into the A/C evaporator core.
A/C Compressor and Clutch Assembly
NOTE:
- Internal A/C compressor components are not serviced separately. The Visteon SC115 A/C compressor is serviced only as an assembly. The clutch disc and hub, clutch pulley and bearing, and clutch field coil are serviceable.
- Installation of a new suction accumulator is not required when repairing the air conditioning system, except when there is physical evidence of contamination from a failed A/C compressor or damage to the suction accumulator.
The Visteon SC115 A/C compressor has the following characteristics:
- Tangential mount, three-lug design.
- The single manifold block of the compressor manifold and tube assembly fits to the suction and discharge ports. Two O-ring seals are used for sealing.
- An eccentric bushing is driven by the shaft of the A/C compressor.
- An orbiting scroll driven by the eccentric bushing compresses the refrigerant gas against the walls of the fixed scroll.
- A single reed-type discharge valve mounted on the back of the fixed scroll. There are no suction valves.
- A non-serviceable shaft seal fully supported on both sides by bearings.
- The A/C compressor uses PAG oil or equivalent. This oil contains special additives required for the A/C compressor.
- The A/C compressor oil from vehicles equipped with a SC115 A/C compressor may have some slightly dark-colored streaks while maintaining normal oil viscosity. This is normal for this A/C compressor because of break-in wear of the scroll seals that can discolor the oil.
- Use standard oil matching procedures when installing new compressors.
When battery voltage is applied to the A/C compressor clutch field coil, the clutch disc and hub assembly is drawn toward the A/C clutch pulley. The magnetic force locks the clutch disc and hub assembly and the A/C clutch pulley together as one unit, causing the compressor shaft to rotate. When battery voltage is removed from the A/C compressor clutch field coil, springs in the clutch disc and hub assembly move the clutch disc away from the A/C clutch pulley.
A/C Pressure Relief Valve
An A/C pressure relief valve is incorporated in the compressor A/C manifold and tube to:
- relieve unusually high refrigerant system discharge pressure buildups. For specifications regarding operating pressure(s), refer to Specifications.
- prevent damage to the A/C compressor and other system components.
- avoid total refrigerant loss by closing after the excessive pressure has been relieved.
A/C Condenser Core
NOTE: Installation of a new suction accumulator is not required when repairing the air conditioning system, except when there is physical evidence of contamination from a failed A/C compressor or damage to the suction accumulator.
The A/C condenser core has the following characteristics:
- It is an aluminum fin-and-tube design heat exchanger located in front of the vehicle radiator.
- It cools compressed refrigerant gas by allowing air to pass over fins and tubes to extract heat and by condensing gas to liquid refrigerant as it is cooled.
Refrigerant Lines
NOTE: Installation of a new suction accumulator is not required when repairing the air conditioning system, except when there is physical evidence of contamination from a failed A/C compressor or damage to the suction accumulator.
The condenser-to-evaporator tube contains high-pressure liquid refrigerant upstream of the A/C evaporator core orifice.
The A/C manifold and tube is attached to the A/C compressor, is sealed with O-ring seals, and has the following features:
- The upstream side contains low-pressure refrigerant gas.
- The downstream side contains high-pressure refrigerant gas and a port to mount the A/C pressure relief valve.
- A fitting is used to mount the A/C pressure sensor. (A long-travel Schrader-type valve stem core is installed in the fitting so that the A/C pressure sensor switch can be removed without discharging the A/C system.)
- A fitting is used to mount a serviceable high-pressure A/C charge port valve.
A/C Evaporator Core
NOTE:
- The evaporator core is not separately serviceable. It is serviced only with the evaporator core housing assembly.
- Installation of a new suction accumulator is not required when repairing the air conditioning system, except when there is physical evidence of contamination from a failed A/C compressor or damage to the suction accumulator.
The A/C evaporator core is the plate/fin type with a unique refrigerant flow path.
- A mixture of refrigerant and oil enters the bottom of the A/C evaporator core through the A/C evaporator core inlet tube and then moves out of the A/C evaporator core through the A/C evaporator core outlet tube.
- This flow pattern accelerates the flow of refrigerant and oil through the A/C evaporator core.
A/C Evaporator Core Orifice
NOTE: A new A/C evaporator core orifice should be installed whenever a new A/C compressor is installed.
The A/C evaporator core orifice has the following characteristics:
- It is located in the evaporator core inlet tube.
- It has filter screens located on the inlet and outlet ends of the tube body.
- The inlet filter screen acts as a strainer for the liquid refrigerant flowing through the A/C evaporator core orifice.
- O-ring seals on the A/C evaporator core orifice prevent the high-pressure liquid refrigerant from bypassing the A/C evaporator core orifice.
- The A/C evaporator core orifice assembly cannot be adjusted or serviced. It must be installed as a unit.
Refrigerant System Dye
Fluorescent refrigerant system dye is added to the refrigerant system at the factory to assist in refrigerant system leak diagnosis using a Rotunda approved ultraviolet blacklight. It is not necessary to add additional dye to the refrigerant system before diagnosing leaks, even if a significant amount of refrigerant has been removed from the system. Replacement suction accumulators are shipped with a fluorescent dye "wafer" included in the desiccant bag, which will dissolve after approximately 30 minutes of continued A/C operation. It is not necessary to add dye after flushing or filtering the refrigerant system because a new suction accumulator is installed as part of the flushing or filtering procedure. Additional refrigerant system dye should only be added if more than 50% of the refrigerant system lubricant capacity has been lost due to a fitting separation, hose rupture, etc.
Suction Accumulator
NOTE: Installation of a new suction accumulator is not required when repairing the air conditioning system, except when there is physical evidence of contamination from a failed A/C compressor or damage to the suction accumulator.
The suction accumulator is mounted to the RH frame rail, below the coolant degas bottle.
After entering the inlet of the suction accumulator, heavier oil-laden refrigerant contacts an internally mounted dome (which serves as an umbrella) and drips down onto the bottom of the canister.
- A small diameter oil bleed hole, in the bottom of the vapor return tube, allows the accumulated heavier liquid refrigerant and oil mixture to re-enter the compressor suction line at a controlled rate.
- As the heavier mixture passes through the small diameter liquid bleed hole, it has a second chance to vaporize and recirculate through the A/C compressor without causing compressor damage due to slugging.
- A fine mesh screened filter fits tightly around the bottom of the vapor return tube to filter out refrigerant system contaminant particles.
- A desiccant bag is mounted inside the canister to absorb any moisture which may be in the refrigerant system.
- A fitting located on the side of the suction accumulator is used to mount a serviceable low-pressure A/C charge port valve.
A/C Pressure Sensor
The A/C pressure sensor allows the PCM to monitor A/C compressor discharge pressure.
- A valve depressor inside of the threaded end of the A/C pressure sensor depresses a Schrader-type valve stem on the compressor discharge portion of the compressor manifold and tube assembly.
- This allows the A/C compressor discharge pressure to be monitored by the PCM.
- The A/C compressor sensor provides a voltage signal that is proportional to the A/C compressor discharge pressure.
- The PCM uses this information for A/C clutch control, cooling fan control and idle speed.
- It is not necessary to recover the refrigerant before removing the A/C pressure sensor.
Low-Charge Protection Switch
The low-charge protection switch (19E561) is used to prevent A/C compressor damage in the event of a low refrigerant charge.
- The electrical switch contacts open when the suction pressure drops below normal levels. The contacts close when the suction pressure rises. For specifications regarding operating pressure(s), refer to Specifications.
- When the low-charge protection switch contacts open, the A/C clutch field coil is de-energized and compressor operation stops.
- The low-charge protection switch is mounted on a Schrader valve-type fitting on the top of the suction accumulator/drier.
- A valve depressor, located inside the threaded end of the low-charge protection switch, presses in on the Schrader valve stem, allowing the suction pressure inside the suction accumulator/drier to control the operation of the low-charge protection switch.
- It is not necessary to discharge the refrigerant system to remove the low-charge protection switch.
Spring Lock Coupling:
Spring Lock Coupling
The spring lock coupling is a refrigerant line coupling held together by a garter spring inside a circular cage.
- When the coupling is connected together, the flared end of the female fitting slips behind the garter spring inside the cage of the male fitting.
- The garter spring and cage then prevent the flared end of the female fitting from pulling out of the cage.
- Use only the O-ring seals listed in the Ford Master Parts Catalog for the spring lock coupling.
- A plastic indicator ring is used on the spring lock couplings of the A/C evaporator core to indicate, during vehicle assembly, that the coupling is connected. Once the coupling is connected, the indicator ring is no longer necessary but will remain captive by the coupling near the cage opening.
- The indicator ring may also be used during service operations to indicate connection of the coupling.
- An A/C tube lock coupling clip may be used to secure the coupling but is not required.
Peanut Fitting
Some components use peanut-shaped refrigerant fittings instead of spring lock couplings.
- The male and female blocks of the peanut fitting are retained with a nut.
- An O-ring seal is installed around the tube on the male block.
- Support the female fitting with a wrench to prevent twisting of the tubes.
- When correctly assembled, the male and female fittings should be flush.
- Use only the O-ring seals listed in the Ford Master Parts Catalog for the peanut fitting.
Service Gauge Port Valves
The high-pressure service gauge port valve is located on the compressor manifold and tube assembly near the condenser fitting.
The low-pressure service gauge port valve is located on the evaporator-to-suction accumulator line near the evaporator fitting.
The fitting is an integral part of the refrigeration line or component.
- Special couplings are required for both the high-side and low-side service gauge ports.
- A very small amount of leakage will always be detectable around the Schrader-type valve with the service gauge port valve cap removed, and is considered normal. A new Schrader-type valve core can be installed if the seal leaks excessively.
- The service gauge port valve caps are used as primary seals in the refrigerant system to prevent leakage through the Schrader-type valves from reaching the atmosphere. Always install and tighten the A/C service gauge port valve caps to the correct torque after they are removed.