Heating and Air Conditioning System Troubleshooting
Refrigerant Quick-Check Procedure for R-134a Expansion Valve And Orifice Tube Systems
Note: This procedure does not call for the installation of the manifold gauge set. The procedure should be used only as an indication of the actual system condition. For the detailed troubleshooting procedures, refer to the "Problem Solving Procedure" section.
Note: In order to use this procedure, the temperature of the ambient air must be at least 21°C (70°F).
1. Start the engine and run the engine at approximately 1000 rpm. Move the control knob on the air conditioner to the position of MAXIMUM so that cooling is at a maximum. In order to stabilize the system, put the fan switch in the HIGH position and operate the system for a minimum of 10 minutes.
For systems that have air conditioner quick disconnects, the dryer can be removed without recovering the refrigerant.
* Replace the receiver-dryer. Refer to the Service Manual, SENR5664, "Receiver-Dryer - Remove and Install" section in Disassembly and Assembly.
* Perform a leak test. Refer to the Service Manual, SENR5664, "Refrigerant Leakage - Test" section in Testing and Adjusting.
* Perform a performance check. Refer to "Performance Checks for the Air Conditioning System" section.
2. Check for restrictions that are present in the refrigerant lines from the compressor to the receiver-dryer. The refrigerant lines and the components that are high pressure and high temperature come from the outlet side of the compressor. The lines go to the inlet side of the expansion valve or orifice tube. The outlet side will be warm during normal operation. Heavy frost or a decrease in the temperature in a line or in a component on the high pressure side may be an indication of a restriction or blockage.
1. If there is no evidence of a restriction in the condenser coil, the receiver-dryer or refrigerant lines from the compressor to the receiver-dryer, use the procedure in Step 3.
2. If there is a restriction in the condenser coil, the receiver-dryer or refrigerant lines from the compressor to the receiver-dryer, perform the following procedures.
* Recover the refrigerant. Refer to the Service Manual, SENR5664, "Refrigerant Recovery" section.
* Remove the restriction or replace the component.
* Evacuate the system. Refer to the Service Manual, SENR5664, "Refrigerant System - Evacuate" section in Testing and Adjusting.
* Charge the system with the correct amount of refrigerant. Measure the refrigerant by weight. Refer to the Service Manual, SENR5664, "Refrigerant System - Charge" section in Testing and Adjusting.
* Perform a leak test. Refer to the Service Manual, SENR5664, "Refrigerant Leakage - Test"section in Testing and Adjusting.
* Perform a performance check. Refer to "Performance Checks for the Air Conditioning System" section.
3. If frost is present on the expansion valve, check the moisture indicator on the receiver-dryer. If the indicator is pink or white, and the receiver does not have air conditioner quick disconnects, perform the following procedures.
* Recover the refrigerant. Refer to the Service Manual, SENR5664, "Refrigerant Recovery" section.
* Replace the receiver-dryer. Refer to the Service Manual, SENR5664, "Receiver-Dryer - Remove and Install" section in Disassembly and Assembly.
* Evacuate the system. Refer to the Service Manual, SENR5664, "Refrigerant System - Evacuate" section in Testing and Adjusting.
* Charge the system with the correct amount of refrigerant. Measure the refrigerant by weight. Refer to the Service Manual, SENR5664, "Refrigerant System - Charge" section in Testing and Adjusting.
* Perform a leak test. Refer to the Service Manual, SENR5664, "Refrigerant Leakage - Test" section in Testing and Adjusting.
* Perform a performance check. Refer to "Performance Checks for the Air Conditioning System" section.
Refer to the Service Manual, SENR5664, "Receiver-Dryer - Remove and Install" section if the receiver-dryer has air conditioner quick disconnects. Refer to the Service Manual, SENR5664, "In-Line refrigerant Dryer - Remove and Install" section if the in-line dryer has air conditioner quick disconnects.
4. On air conditioning systems that have a dryer with a moisture indicator, if the indicator is blue and the system is free of moisture, the expansion valve may be blocked.
* Recover the refrigerant. Refer to the Service Manual, SENR5664, "Refrigerant Recovery" section.
* Replace the expansion valve. Refer to the Service Manual, SENR5664, "Expansion Valve - (Air Conditioner) Remove and Install" section in Disassembly and Assembly.
* Evacuate the system. Refer to the Service Manual, SENR5664, "Refrigerant System - Evacuate" section in Testing and Adjusting.
* Charge the system with the correct amount of refrigerant. Measure the refrigerant by weight. Refer to the Service Manual, SENR5664, "Refrigerant System - Charge" section in Testing and Adjusting.
* Perform a leak test. Refer to the Service Manual, SENR5664, "Refrigerant Leakage - Test"section in Testing and Adjusting.
* Perform a performance check. Refer to "Performance Checks for the Air Conditioning System" section.
3. Low system charge is indicated. Perform a leak test.
Note: If the system is very low on refrigerant, a partial charge may be needed before you perform a leak test.
* Recover the remaining refrigerant. Refer to the Service Manual, SENR5664, "Refrigerant Recovery" section.
* Repair all leaks.
* Evacuate the system. Refer to the Service Manual, SENR5664, "Refrigerant System - Evacuate" section in Testing and Adjusting.
* Charge the system with the correct amount of refrigerant. Measure the refrigerant by weight. Refer to the Service Manual, SENR5664, "Refrigerant System - Charge" section in Testing and Adjusting.
* Perform a performance check. Refer to "Performance Checks for the Air Conditioning System" section.
4. Feel the low pressure line and feel the high pressure line at the compressor. In order to indicate normal systems operation, the high pressure line to the condenser coil must be warm, while the low pressure line to the evaporator coil must be cool.
* The high pressure line and the low pressure line at the compressor have a minimal temperature difference between the two lines. Use the procedure in Step 5.
* If there is a definite temperature difference between the high pressure line and the low pressure line at the compressor, the system is operating correctly. The high pressure line will be warm. The low pressure line will be cool. Use the procedure in Step 6.
5.If the system has no refrigerant charge or if the system is nearly empty of refrigerant charge, perform the following procedure:
* Stop the engine.
* Perform a partial charge of the system.
* Perform a leak test. Refer to the Service Manual, SENR5664, "Refrigerant Leakage - Test" section in Testing and Adjusting.
* Repair leaks.
* Evacuate the system. Refer to the Service Manual, SENR5664, "Refrigerant System - Evacuate" section in Testing and Adjusting.
* Charge the system with the correct amount of refrigerant. Measure the refrigerant by weight. Refer to the Service Manual, SENR5664, "Refrigerant System - Charge" section in Testing and Adjusting.
* Perform a performance check. Refer to "Performance Checks for the Air Conditioning System" section.
6. An overcharge of the system is possible even though the system can have a definite difference in temperature at the low pressure line and at the high pressure line.
Note: For an orifice tube system, an additional inspection is required. The additional inspection procedure determines the level of the system charge. When both the inlet of the accumulator and the outlet of the accumulator are cool to the touch, the system is charged correctly.
If the outlet is warmer than the inlet, the system may not contain enough refrigerant.
* Recover the refrigerant. Refer to the Service Manual, SENR5664, "Refrigerant Recovery" section.
* Evacuate the system. Refer to the Service Manual, SENR5664, "Refrigerant System - Evacuate" section in Testing and Adjusting.
* Charge the system with the correct amount of refrigerant. Measure the refrigerant by weight. Refer to the Service Manual, SENR5664, "Refrigerant System - Charge" section in testing and adjusting.
* Perform a leak test. Refer to the Service Manual, SENR5664, "Refrigerant Leakage - Test" section in Testing and Adjusting.
* Perform a performance check. Refer to "Performance Checks for the Air Conditioning System" section.
Refrigerant Quick-Check Procedure for R-134a Expansion Valve And Orifice Tube Systems
Note: This procedure does not call for the installation of the manifold gauge set. The procedure should be used only as an indication of the actual system condition. For the detailed troubleshooting procedures, refer to the "Problem Solving Procedure" section.
Note: In order to use this procedure, the temperature of the ambient air must be at least 21°C (70°F).
1. Start the engine and run the engine at approximately 1000 rpm. Move the control knob on the air conditioner to the position of MAXIMUM so that cooling is at a maximum. In order to stabilize the system, put the fan switch in the HIGH position and operate the system for a minimum of 10 minutes.
For systems that have air conditioner quick disconnects, the dryer can be removed without recovering the refrigerant.
* Replace the receiver-dryer. Refer to the Service Manual, SENR5664, "Receiver-Dryer - Remove and Install" section in Disassembly and Assembly.
* Perform a leak test. Refer to the Service Manual, SENR5664, "Refrigerant Leakage - Test" section in Testing and Adjusting.
* Perform a performance check. Refer to "Performance Checks for the Air Conditioning System" section.
2. Check for restrictions that are present in the refrigerant lines from the compressor to the receiver-dryer. The refrigerant lines and the components that are high pressure and high temperature come from the outlet side of the compressor. The lines go to the inlet side of the expansion valve or orifice tube. The outlet side will be warm during normal operation. Heavy frost or a decrease in the temperature in a line or in a component on the high pressure side may be an indication of a restriction or blockage.
1. If there is no evidence of a restriction in the condenser coil, the receiver-dryer or refrigerant lines from the compressor to the receiver-dryer, use the procedure in Step 3.
2. If there is a restriction in the condenser coil, the receiver-dryer or refrigerant lines from the compressor to the receiver-dryer, perform the following procedures.
* Recover the refrigerant. Refer to the Service Manual, SENR5664, "Refrigerant Recovery" section.
* Remove the restriction or replace the component.
* Evacuate the system. Refer to the Service Manual, SENR5664, "Refrigerant System - Evacuate" section in Testing and Adjusting.
* Charge the system with the correct amount of refrigerant. Measure the refrigerant by weight. Refer to the Service Manual, SENR5664, "Refrigerant System - Charge" section in Testing and Adjusting.
* Perform a leak test. Refer to the Service Manual, SENR5664, "Refrigerant Leakage - Test"section in Testing and Adjusting.
* Perform a performance check. Refer to "Performance Checks for the Air Conditioning System" section.
3. If frost is present on the expansion valve, check the moisture indicator on the receiver-dryer. If the indicator is pink or white, and the receiver does not have air conditioner quick disconnects, perform the following procedures.
* Recover the refrigerant. Refer to the Service Manual, SENR5664, "Refrigerant Recovery" section.
* Replace the receiver-dryer. Refer to the Service Manual, SENR5664, "Receiver-Dryer - Remove and Install" section in Disassembly and Assembly.
* Evacuate the system. Refer to the Service Manual, SENR5664, "Refrigerant System - Evacuate" section in Testing and Adjusting.
* Charge the system with the correct amount of refrigerant. Measure the refrigerant by weight. Refer to the Service Manual, SENR5664, "Refrigerant System - Charge" section in Testing and Adjusting.
* Perform a leak test. Refer to the Service Manual, SENR5664, "Refrigerant Leakage - Test" section in Testing and Adjusting.
* Perform a performance check. Refer to "Performance Checks for the Air Conditioning System" section.
Refer to the Service Manual, SENR5664, "Receiver-Dryer - Remove and Install" section if the receiver-dryer has air conditioner quick disconnects. Refer to the Service Manual, SENR5664, "In-Line refrigerant Dryer - Remove and Install" section if the in-line dryer has air conditioner quick disconnects.
4. On air conditioning systems that have a dryer with a moisture indicator, if the indicator is blue and the system is free of moisture, the expansion valve may be blocked.
* Recover the refrigerant. Refer to the Service Manual, SENR5664, "Refrigerant Recovery" section.
* Replace the expansion valve. Refer to the Service Manual, SENR5664, "Expansion Valve - (Air Conditioner) Remove and Install" section in Disassembly and Assembly.
* Evacuate the system. Refer to the Service Manual, SENR5664, "Refrigerant System - Evacuate" section in Testing and Adjusting.
* Charge the system with the correct amount of refrigerant. Measure the refrigerant by weight. Refer to the Service Manual, SENR5664, "Refrigerant System - Charge" section in Testing and Adjusting.
* Perform a leak test. Refer to the Service Manual, SENR5664, "Refrigerant Leakage - Test"section in Testing and Adjusting.
* Perform a performance check. Refer to "Performance Checks for the Air Conditioning System" section.
3. Low system charge is indicated. Perform a leak test.
Note: If the system is very low on refrigerant, a partial charge may be needed before you perform a leak test.
* Recover the remaining refrigerant. Refer to the Service Manual, SENR5664, "Refrigerant Recovery" section.
* Repair all leaks.
* Evacuate the system. Refer to the Service Manual, SENR5664, "Refrigerant System - Evacuate" section in Testing and Adjusting.
* Charge the system with the correct amount of refrigerant. Measure the refrigerant by weight. Refer to the Service Manual, SENR5664, "Refrigerant System - Charge" section in Testing and Adjusting.
* Perform a performance check. Refer to "Performance Checks for the Air Conditioning System" section.
4. Feel the low pressure line and feel the high pressure line at the compressor. In order to indicate normal systems operation, the high pressure line to the condenser coil must be warm, while the low pressure line to the evaporator coil must be cool.
* The high pressure line and the low pressure line at the compressor have a minimal temperature difference between the two lines. Use the procedure in Step 5.
* If there is a definite temperature difference between the high pressure line and the low pressure line at the compressor, the system is operating correctly. The high pressure line will be warm. The low pressure line will be cool. Use the procedure in Step 6.
5.If the system has no refrigerant charge or if the system is nearly empty of refrigerant charge, perform the following procedure:
* Stop the engine.
* Perform a partial charge of the system.
* Perform a leak test. Refer to the Service Manual, SENR5664, "Refrigerant Leakage - Test" section in Testing and Adjusting.
* Repair leaks.
* Evacuate the system. Refer to the Service Manual, SENR5664, "Refrigerant System - Evacuate" section in Testing and Adjusting.
* Charge the system with the correct amount of refrigerant. Measure the refrigerant by weight. Refer to the Service Manual, SENR5664, "Refrigerant System - Charge" section in Testing and Adjusting.
* Perform a performance check. Refer to "Performance Checks for the Air Conditioning System" section.
6. An overcharge of the system is possible even though the system can have a definite difference in temperature at the low pressure line and at the high pressure line.
* Recover the refrigerant. Refer to the Service Manual, SENR5664, "Refrigerant Recovery" section.
* Evacuate the system. Refer to the Service Manual, SENR5664, "Refrigerant System - Evacuate" section in Testing and Adjusting.
* Charge the system with the correct amount of refrigerant. Measure the refrigerant by weight. Refer to the Service Manual, SENR5664, "Refrigerant System - Charge" section in Testing and Adjusting.
* Perform a performance check. Refer to the "Performance Checks for the Air Conditioning System" section.
* Evacuate the system. Refer to the Service Manual, SENR5664, "Refrigerant System - Evacuate" section in Testing and Adjusting.
* Charge the system with the correct amount of refrigerant. Measure the refrigerant by weight. Refer to the Service Manual, SENR5664, "Refrigerant System - Charge" section in Testing and Adjusting.
* Perform a performance check. Refer to the "Performance Checks for the Air Conditioning System" section.
Note: For an orifice tube system, an additional inspection is required. The additional inspection procedure determines the level of the system charge. When both the inlet of the accumulator and the outlet of the accumulator are cool to the touch, the system is charged correctly.
If the outlet is warmer than the inlet, the system may not contain enough refrigerant.
* Recover the refrigerant. Refer to the Service Manual, SENR5664, "Refrigerant Recovery" section.
* Evacuate the system. Refer to the Service Manual, SENR5664, "Refrigerant System - Evacuate" section in Testing and Adjusting.
* Charge the system with the correct amount of refrigerant. Measure the refrigerant by weight. Refer to the Service Manual, SENR5664, "Refrigerant System - Charge" section in testing and adjusting.
* Perform a leak test. Refer to the Service Manual, SENR5664, "Refrigerant Leakage - Test" section in Testing and Adjusting.
* Perform a performance check. Refer to "Performance Checks for the Air Conditioning System" section.
