Air Conditioning
AIR CONDITIONINGThe A/C refrigerant system is a clutch cycling orifice tube type. The system components are:
- A/C compressor
- A/C clutch
- A/C condenser core
- A/C evaporator core
- Suction accumulator
- Connecting refrigerant lines
The refrigeration system operation is controlled by the following:
- A/C evaporator core orifice
- A/C cycling switch
- A/C pressure cutoff switch
The refrigerant system incorporates an A/C compressor controlled by an A/C cycling switch. The A/C cycling switch senses pressure in the suction accumulator to control operation of the A/C compressor.
An A/C compressor pressure relief valve is installed in the A/C manifold and tube to protect the compressor against excessively high refrigerant pressures. An 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 - Visteon FS-10
NOTE:
- Internal A/C compressor components are not serviced separately. The FS-10 A/C compressor is serviced only as an assembly. The A/C clutch disc and hub, A/C clutch pulley, A/C clutch field coil and the shaft seal are serviceable.
- Whenever a new A/C compressor is installed due to a failure that produces foreign material in the system, also install a new suction accumulator and the A/C evaporator core orifice.
The FS-10 A/C compressor has the following characteristics:
- A ten-cylinder swashplate design utilizing the tangential design mount.
- A one-piece lip-type seal (replaceable from the front of the A/C compressor) is used to seal it at the shaft opening in the assembly.
- Five double-acting pistons operate within the cylinder assembly. The pistons are actuated by a swashplate that changes the rotating action of the shaft to a reciprocating force.
- Reed-type discharge valves are located between the cylinder assembly and the head at each end of the A/C compressor.
- The A/C compressor uses PAG Refrigerant Compressor Oil (R-134a Systems) or equivalent. This oil contains special additives required for the A/C compressor.
The magnetic A/C clutch has the following characteristics:
- It drives the compressor shaft.
- When battery positive voltage (B+) is applied to the A/C 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 together as one unit, causing the compressor shaft to rotate.
- When B+ is removed from the A/C clutch field coil, springs in the clutch disc and hub assembly move the clutch disc away from the A/C clutch
A/C Compressor Pressure Relief Valve
An A/C compressor pressure relief valve is incorporated in the compressor manifold and tube to:
- relieve unusually high refrigerant system discharge pressure buildups.
- 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
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 condense refrigerant gas to liquid refrigerant as is cooled.
Refrigerant Lines
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 replaced 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.
- Contains the pressure relief valve.
- The downstream side also contains a fitting used to mount the A/C pressure cutoff switch. A long-travel Schrader valve-type stem core is installed in the fitting so that the A/C pressure cutoff switch can be removed without discharging the A/C system.
A/C Evaporator Core
NOTE: If an evaporator core leak is suspected, the evaporator core must be vacuum leak tested before it is removed.
The A/C evaporator core is a 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.
- The A/C evaporator core is located in the evaporator core housing at the RH engine compartment side of the dash panel.
A/C Evaporator Core Orifice
NOTE: The A/C evaporator core orifice should be replaced following A/C compressor failures that produce foreign material in the system.
The A/C evaporator core orifice has the following characteristics:
- It is located in the A/C 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-rings on the A/C evaporator core orifice prevent the high-pressure liquid refrigerant from bypassing the A/C evaporator core orifice.
- Adjustment or service cannot be made to the A/C evaporator core orifice assembly. It must be replaced 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 contamination from a failed A/C compressor or damage to the suction accumulator.
The inlet tube of the suction accumulator attaches directly to the A/C evaporator core outlet tube and the outlet tube of the suction accumulator attaches to the A/C manifold and tube.
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 suction accumulator is used to attach the A/C cycling switch. A long-travel Schrader valve-type stem core is installed in the fitting so that the A/C cycling switch can be removed without discharging the A/C system.
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.
A/C Cycling Switch
The A/C cycling switch is mounted on a Schrader valve-type fitting on the side 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.
- When the A/C cycling switch contacts close, the A/C request signal circuit is completed to the PCM.
- When the A/C cycling switch contacts open, the A/C request signal circuit is interrupted and compressor operation stops.
- The A/C cycling switch will control the A/C evaporator core pressure at a point where the plate/fin surface temperature will be maintained slightly above freezing.
- This prevents icing of the A/C evaporator core and blockage of air flow.
- It is not necessary to discharge the refrigerant system to remove the A/C cycling switch.
A/C Pressure Cutoff Switch - 5.4L and 6.8L
The A/C pressure cutoff switch is used to interrupt the A/C compressor operation in the event of high system discharge pressures.
- The A/C pressure cutoff switch is mounted on a Schrader valve-type fitting on the high pressure side of the A/C manifold and tube.
- A valve depressor, located inside the threaded end of the A/C pressure cutoff switch, presses on the Schrader valve stem.
- This allows the A/C pressure cutoff switch to monitor the compressor discharge pressure.
- When the compressor discharge pressure rises, the switch contacts open and the A/C request signal circuit to the PCM is interrupted. When the pressure drops, the contacts close to complete the A/C request signal circuit to the PCM.
- It is not necessary to discharge the refrigerant system to remove the A/C pressure cutoff switch.
Dual Function Pressure Switch - 6.0L Diesel
The dual function pressure switch (DFPS) is used to interrupt A/C compressor operation in the event of high system discharge pressures.
- The dual function pressure switch is mounted on a Schrader valve-type fitting on the high pressure side of the compressor manifold and tube assembly.
- A valve depressor, located inside the threaded end of the DFPS, presses on the Schrader valve stem.
- This allows the DFPS to monitor the compressor discharge pressure.
- The DFPS has two sets of electrical contacts. One set of contacts is normally closed and is used for A/C high pressure cutoff.
- When the A/C compressor discharge pressure rises, the switch contacts open, disengaging the A/C compressor. When the compressor discharge pressure drops, the switch contacts return to the closed position, and A/C compressor operation resumes.
- The second set of electrical contacts in the DFPS is used for engine cooling fan control.
- It is not necessary to recover the refrigerant to remove the DFPS.
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 as a seal between the two halves of the A/C 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 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.
Tube-O Fitting
The condenser fittings are the tube-O type.
- The male and female portions of the peanut fitting are retained with a nut.
- An O-ring seal is installed around the tube on the male side of the fitting.
- Support the female fitting with a wrench to prevent twisting of the tubes when disconnecting.
- 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 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.