Main Climate Control
AIR CONDITIONINGThe A/C refrigerant system is a clutch cycling orifice tube type. The system components are:
- A/C compressor
- A/C clutch
- condenser core
- evaporator core
- suction accumulator
- connecting refrigerant lines
The refrigeration system operation is controlled by the:
- evaporator core orifice.
- A/C cycling switch.
- A/C pressure relief valve.
- pressure cutoff switch.
The refrigerant system incorporates and A/C compressor controlled by an A/C cycling switch and refrigerant containment switch (high-pressure cutoff switch). The A/C cycling switch senses low-side refrigerant pressure to control A/C compressor operation and prevent evaporator core freeze up. The refrigerant containment switch senses high-side refrigerant pressure to interrupt A/C compressor operation in the event of excessively high refrigerant pressure.
An A/C pressure relief valve is installed in the compressor manifold and tube assembly to protect the refrigerant system against excessively high refrigerant pressures.
An evaporator core orifice is installed in the evaporator core inlet tube to meter the liquid refrigerant into the evaporator core.
A/C Compressor and Clutch Assembly - Visteon SC115
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, the clutch pulley and bearing, and the 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 system 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 design - three lugs.
- 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.
- Single reed-type discharge valve mounted on the back of the fixed scroll. There are no suction valves.
- 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 an Visteon SC115 A/C compressor may have some slightly dark colored streaks while maintaining a 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.
The magnetic A/C clutch has the following characteristics:
- It drives the compressor shaft.
- When battery voltage is applied to the A/C compressor clutch field coil, the clutch disc and hub assembly is drawn toward the clutch pulley.
- The magnetic force locks the clutch disc and hub assembly and the 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 plate away from the clutch pulley.
A/C Pressure Relief Valve
An A/C pressure relief valve is incorporated in the compressor manifold and tube assembly 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.
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 system contamination from a failed A/C compressor or damage to the suction accumulator.
The 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 system contamination from a failed A/C compressor or damage to the suction accumulator.
The condenser to evaporator line contains high pressure liquid refrigerant upstream of the evaporator core orifice.
The compressor manifold and tube assembly is attached to the A/C compressor and has the following features:
- The upstream side contains low pressure refrigerant gas.
- The downstream side contains high pressure refrigerant gas.
- A serviceable high pressure A/C charge port valve is located on the downstream side.
- The downstream side also contains a fitting used to mount the pressure cutoff switch. A long-travel Schrader-type valve stem core is installed in the fitting so that the pressure cutoff switch can be removed without discharging the A/C system.
Evaporator Core
NOTE: Installation of a new suction accumulator is not required when repairing the air conditioning system except when there is physical evidence of system contamination from a failed A/C compressor or damage to the suction accumulator.
The evaporator core is the plate/fin type with a unique refrigerant flow path.
- A mixture of refrigerant and oil enters the bottom of the evaporator core through the evaporator core inlet tube and is routed so it flows through the partitioned plate/fin sections.
- Refrigerant then moves out of the evaporator core through the evaporator core outlet tube.
Evaporator Core Orifice
NOTE: A new evaporator core orifice should be installed whenever a new A/C compressor is installed.
The 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 evaporator core orifice prevent the high-pressure liquid refrigerant from bypassing the evaporator core orifice.
- Adjustment or service cannot be made to the evaporator core orifice assembly, a new evaporator core orifice assembly must be installed as a unit.
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 system contamination from a failed A/C compressor or damage to the suction accumulator.
The suction accumulator is mounted to the right of the vehicle centerline. The inlet tube of the suction accumulator attaches directly to the evaporator core outlet tube and the outlet tube of the suction accumulator attaches to the compressor manifold and tube assembly.
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 top of the suction accumulator is used to attach the A/C cycling switch. A long-travel Schrader-type valve stem core is installed in the fitting so that the A/C cycling switch can be removed without discharging the A/C system.
A/C Cycling Switch
The A/C cycling switch is mounted on a Schrader valve-type fitting on the top of the suction accumulator.
- A valve depressor, located inside the threaded end of the A/C cycling switch, presses in on the Schrader valve stem.
- This allows the suction pressure inside the suction accumulator to control the operation of the A/C cycling switch.
- The electrical switch contacts open when the suction pressure drops. The contacts close when the suction pressure rises. For specifications regarding operating pressure(s), refer to Specifications.
- When the A/C cycling switch contacts close, the A/C compressor clutch field coil is energized.
- When the A/C cycling switch contacts open, the A/C compressor clutch field coil is de-energized and A/C compressor operation stops.
- The A/C cycling switch will control the evaporator core pressure at a point where the plate/fin surface temperature will be maintained slightly above freezing.
- This prevents icing of the evaporator core and blockage of airflow.
- It is not necessary to discharge the refrigerant system to remove the A/C cycling switch.
Pressure Cutoff Switch
The pressure cutoff switch is used to interrupt A/C compressor operation in the event of high system discharge pressures.
- The pressure cutoff switch is mounted on a Schrader valve-type fitting on the high pressure side.
- A valve depressor, located inside the threaded end of the pressure cutoff switch, presses on the Schrader valve stem.
- This allows the pressure cutoff switch to monitor the compressor discharge pressure.
- When the A/C compressor discharge pressure rises, the switch contacts open, disengaging the A/C compressor. When the pressure drops, the contacts close to allow operation of the A/C compressor.
- It is not necessary to discharge the refrigerant system to remove the pressure cutoff 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.
- Three O-ring seals are used to seal between the two halves of the condenser core couplings, all other couplings have two O-ring seals.
- 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 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:
Peanut Fitting
When disconnecting or connecting peanut fittings, observe the following:
- The male and female blocks of the peanut fitting are retained with a nut.
- Support the female fitting with a wrench to prevent twisting of the tubes.
- An-O-ring seal is installed around the tube on the male block.
- When correctly assembled, the male and female fittings should be flush.
- Use only the O-ring seal listed in the Ford Master Parts Catalog.
Tube-O Fitting:
Tube-O Fitting
When disconnecting or connecting tube-O fittings, observe the following:
- The male and female portions of the fitting are retained with a nut.
- Support the female fitting with a wrench to prevent twisting of the tubes when disconnecting.
- An O-ring seal is installed around the tube on the male side of the fitting.
- Use only the O-ring seal listed in the Ford Master Parts Catalog.
Service Gauge Port Valves
The high pressure service gauge port valve is located on the compressor manifold and tube assembly.
The low pressure service gauge port valve is located on the suction accumulator.
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 new Schrader-type valve core can be installed if the seal leaks.
- Always install the A/C charging valve cap on the service gauge port valves after repairing the refrigerant system.