Thursday, November 24, 2011

How to Replace Vehicles AC Expansion Valve?

If you need dis-assembly or replacement instructions for any other auto/car part, or you want to ask question related to your car/truck jeep problem then please leave the comment with your details, so I can provide you the required instructions and solutions.


The AC Expansion Valve is the component of a refrigeration system that regulates the rate of flow of refrigerant into the evaporator as governed by the action of the remote bulb-sensing tailpipe temperatures.


Before replacing AC Expansion Valve,its advisable to INSPECT & TEST the Expansion Valve.


For inspection and testing procedure.Click the link below:---



How to Inspect Vehicles A/C Expansion Valve?


How to Test Vehicles AC Expansion Valve?

http://repairhelpcenter.blogspot.com/2011/11/how-to-test-vehicles-ac-expansion-valve.html

Once its confirmed that Valve is faulty,then proceed further to replace the Expansion valve.


To replace a standard thermostatic expansion valve (TXV):
  • Place the ignition switch in the OFF position.
  • Disconnect the battery cable.
  • Purge the system of refrigerant; use the proper recovery equipment.
  • Remove the insulation tape from the remote bulb.
  • Loosen the clamp to free the remote bulb.
  • Disconnect the external equalizer, if the TXV is so equipped.
  • Remove the liquid line from the inlet of the TXV.
  • Remove and discard the O-ring, if equipped.
  • Inspect the inlet screen.
If it's clogged:
  • Clean and replace the screen.
  • Install new O-rings on the liquid line fitting, if equipped.
  • Attach the liquid line to the TXV. Tighten to proper torque.
  • Reconnect the external equalizer tube, if equipped.
  • Position the remote bulb and secure it with a clamp.
  • Tape the remote bulb to prevent it from sensing ambient air.
  • Replace the access panels and any hardware previously removed.
  • Reconnect the battery.
  • Leak test, evacuate, and charge system with refrigerant.
  • Do a performance test if required.
If it is not clogged:
  • Place the ignition switch in the OFF position. Disconnect the battery cable. Purge the system of refrigerant; use the proper recovery equipment.
  • Remove the evaporator inlet fitting from the outlet of the TXV.
  • Remove and discard the O-ring, if equipped.
  • Remove the holding clamp (if provided on the TXV) and carefully lift the TXV from the evaporator.
  • Carefully locate the new TXV in the evaporator.
  • Insert new O-ring(s) on evaporator inlet, if equipped.
  • Attach evaporator inlet to the TXV outlet. Tighten to proper torque.
  • Install new O-rings on the liquid line fitting, if equipped.
  • Attach the liquid line to the TXV. Tighten to proper torque.
  • Reconnect the external equalizer tube, if equipped.
  • Position the remote bulb and secure it with a clamp.
  • Tape the remote bulb to prevent it from sensing ambient air.
  • Replace the access panels and any hardware previously removed.
  • Reconnect the battery.
  • Leak test, evacuate, and charge system with refrigerant.
  • Do a performance test if required.
To replace an H-thermostatic expansion valve:
  • Disconnect the wire connected to the pressure cut-out or pressure differential switch as applicable.
  • Remove the bolt from the line sealing plate found between the suction and liquid lines.
  • Carefully pull the plate from the H-valve.
  • Cover the line openings to prevent the intrusion of foreign matter.
  • Remove and discard the plate to the H-valve gasket.
  • Remove the two screws from the H-valve.
  • Remove the H-valve from the evaporator plate.
  • Remove and discard the H-valve to evaporator plate gasket.
  • Install a new H-valve with gasket.
  • Replace two screws. Torque to 170-230 in.-lb. (20-26N?m).
  • Replace the line plate to H-valve gasket.
  • Hold the line assembly in place and install the bolt. Torque to 170-230 in.-LB (20-26N?m).
  • Replace the access panels and any hardware previously removed.
  • Reconnect the battery.
  • Leak test, evacuate, and charge system with refrigerant.
  • Do a performance test if required.
NOTE
if the expansion valve requires replacement for any reason, replace the Receiver Dryer . it is right in front of the expansion valve and should have prevented the corrosion that ruined the expansion valve. the evaporator would fail next if the expansion valve was open.
CAUTION
Exercise extreme caution, and pay heed to every established safety practice when performing these or any automotive air-conditioning system service procedures.
Cleaning the thermostatic expansion valve:
  1. Remove the diaphragm, the capillary, and the remote bulb assembly.
  2. Remove the superheat adjusting screw. Count the number of turns required to remove the screw. Knowing the number of turn aids in relocating the proper position when reassembling the valve.
  3. Remove the superheat spring and the valve seat. Remove the valve and push rod(s).
  4. Clean the valve and all parts in clean mineral spirits. Let the parts drain and then blow them dry.
  5. Reverse Steps 1-4 and reassemble the valve.
  6. Check the expansion valve for maximum and minimum flow as outlined in this procedure.
  7. If the valve fails to pass the maximum/minimum flow test, then attempt to adjust the superheat spring setting.
  8. If the valve fails the test repeatedly, a new valve must be installed. No further repair is possible.

This details will help.
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Also if you have better understanding of other car AC cooling system parts,then it will help more to troubleshoot the problem.
Check the list below or more help.
Its always advisable to know the AC components working and testing procedure,before replacing any part.
For more details regarding cars AC components.Check out the list of links below:---


How to Perform AC Pressure Test?


How to test Cars AC System?


How to inspect Vehicles A/C Compressor and Clutch?


How to Troubleshoot Vehicles AC Cooling Problem?

http://repairhelpcenter.blogspot.com/2011/11/how-to-troubleshoot-vehicles-ac-cooling.html

How to Replace Vehicles A/C Compressor and Clutch Components?

http://repairhelpcenter.blogspot.com/2011/11/how-to-replace-vehicles-ac-compressor.html

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For car AC related and Heater related solutions. You can refer the options mentioned below:---

Car AC Blows Warm Air ?


How to test AUTO AC pressure?


AUTO Air Conditioning Troubleshooting?



AUTO A/C COOLING PROBLEM?


Fixing refrigerant leak?


How to locate Car AC Refrigerant leak?


CAR AC INTERMITTENT COOLING?


What causes INTERMITTENT COOLING on Car AC system?


Car AC making Noise?


BAD ODOR ON CAR AIR CONDITIONER?



How to Recharge Car's Air Conditioner




For details regarding:--

How does Vehicles Engine cooling system works?


Engine cooling components working?


How to flush cars radiator?



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