Due Air Conditioning System Troubleshooting-VERYGOOD

8/6/2019 Due Air Conditioning System Troubleshooting-VERYGOOD

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Due Air Conditioning System Troubleshooting

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 procedureshould 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 21C(70F).

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 withoutrecovering 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 fromthe compressor to the receiver-dryer, perform the following procedures.

* Recover the refrigerant. Refer to the Service Manual, SENR5664, "Refrigerant Recovery"

section.


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* 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 andAdjusting.

* Perform a leak test. Refer to the Service Manual, SENR5664, "Refrigerant Leakage -

Test"section in Testing and Adjusting.


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 quickdisconnects, perform the following procedures.


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 thereceiver-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 conditionerquick 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.


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* 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.


* 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 andAdjusting.

* Perform a leak test. Refer to the Service Manual, SENR5664, "Refrigerant Leakage -

Test"section in Testing and Adjusting.


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, "RefrigerantRecovery" section.

* Repair all leaks.




Adjusting.


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.


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* If there is a definite temperature difference between the high pressure line and the low pressureline 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.



Refer to the Service Manual, SENR5664, "Refrigerant System - Charge" section in Testing andAdjusting.

* 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 definitedifference 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.




Adjusting.

* Perform a performance check. Refer to the "Performance Checks for the Air ConditioningSystem" 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 andthe 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.


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section.




Refer to the Service Manual, SENR5664, "Refrigerant System - Charge" section in testing andadjusting.

* Perform a leak test. Refer to the Service Manual, SENR5664, "Refrigerant Leakage - Test"

section in Testing and Adjusting.


Posted by Mechanic Trade Specialist at 8:47 AMLabels: Due Air Conditioning System Troubleshooting

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Due Air Conditioning System Troubleshooting-VERYGOOD