CONFIDENTIAL TIBU3826-03

The HVAC system has experienced various improvements in order to increase operator comfort. This Technical Information Bulletin will summarize the improvements to the HVAC and the recommended troubleshooting procedure for air conditioning performance complaints.

A correctly operating HVAC system in the machines that are listed will provide cooling that is equal to other C Series Excavators. The cool down time for each machine will vary due to the ambient air temperature, humidity, and sun load. The HVAC system will meet SAE and ISO requirements when functioning correctly. The output air temperature from the rear vent will range between 9? C (48? F) and 12? C (54? F).

• The failure of the 171-2545 Control As.
• The refrigerant is under charged
• The refrigerant is over charged.

The second root cause is insufficient cooling capacity on a correctly functioning air conditioning system.

• Make sure that the air conditioning system is working correctly.
• The addition of accessory air ducts will improve the airflow.
• Relocate the evaporator core temperature sensor and flash new software. Reference the evaporator core temperature sensor relocation information described in this publication.
• Make sure the drain tubes are functioning correctly.
• Measure the vent temperature and determine if the enhanced air conditioning system described in Special Instruction, REHS1621, "Procedure For Replacement Of Air Conditioner Components" is necessary.

SYSTEM IMPROVEMENTS AND INFORMATION:

A connection in the control module was susceptible to the entry of potting material, which caused intermittent electrical problems. The 171-2545 Control Assembly should be replaced if a controller failure occurs. No controllers with a date code after 15Nov02 have been found to have a failure.

Controller Revision E that was built after the date code of 15Nov02 used dielectric grease and a correction to the software to improve the controller. The reliability of the improvement has been extremely high. The following machines have been built with the Revision E controller and a 15Nov02 date code:

322C (BKJ780-Up, C3R1-Up, HEK130-Up)
325C (BFE650-Up, G1L217-Up, M2K294-Up, S2C139-Up, S3M322-Up,
Y4P398-Up)
330C (DKY1068-Up, B1K175-Up, B2L186-Up, B3M1-Up, B4N182-Up,
D3C224-Up)

A date code is stamped on the controller. Each letter stamped represents a number. The stamp sequence for the code is day month year. Use the information in Table 1 in order to determine the date code of the controller.

Table 1. Example: Code UAUUNM equals 151102 or (15Nov02)

Two new part numbers are available for the replacement of a failed 171-2545 Control Assembly:

The 233-9518 Control Assembly uses software that allows the evaporator core to operate at 2? C (36? F). Do not relocate the evaporator core temperature sensor for systems that use the 233-9518 Control Assembly.

The 231-2790 Control Assembly uses software that allows the evaporator core to operate at ?0.5? C (31? F). The 231-2790 Control Assembly may be installed on any machine that has a relocated evaporator core temperature sensor.

The air conditioning system is sensitive to the amount of refrigerant charged in the system. The air conditioning system must be charged by weight with the correct amount of refrigerant in order to function correctly. The following criteria must be met in order to achieve system requirements:

The air conditioning technician should be familiar with automotive and off highway air conditioning systems. The technician must also have current certifications. The charging equipment, scales, and evacuation equipment must be accurately calibrated. The length of the charging hoses must not exceed 8 feet. The shortest possible hoses should be used for charging.

The refrigerant must be weighed on a digital scale as it is installed in the system. Do not use a sight gauge, a charging cylinder, individual containers, or a set of gauges to measure the amount of the charge. These gauges and containers do not provide the required accuracy.

The performance of the air conditioning system will be affected if the refrigerant charge is not within 45 grams (0.1 lb) of the specified capacity. The refrigerant must be charged by weight with a calibrated electronic refrigerant scale. Use a 168-1958 Charging Scale or the equivalent. If the refrigerant charge is in question, recover the refrigerant, evacuate the system, and charge the refrigerant by weight. Refer to Table 2 for the refrigerant charge capacity.

Table 2. Refrigerant Charge Capacity

NOTE: Certain 322C (BKJ) Excavators may have an incorrect air conditioning instruction plate in the cab. The machines received the correct total refrigerant charge, but received the incorrect instruction plate. Inspect and replace the 110-6393 Instruction Plate in the cab.

NOTE: The total refrigerant charge in the system must be weighed exactly. Make sure the charge lines have only gas in them when starting to charge the system. Make sure the refrigerant in the charge lines is pulled into the air conditioner system after closing the valve on the tank. Refer to RENR3899, "Refrigerant System Charge" and "Manifold Gauge Set (Refrigerant)-Remove" for detailed instructions.

Refer to Table 3 in order to determine if the recharging of the system is required. Make pressure checks after five minutes of operation.

Table 3. Pressure Ranges For The Air Conditioning System
¹This table is for reference only.
²Pressure may be slightly increased in very dry or very humid conditions.
³Pressure before the clutch is disengaged.

The air conditioning refrigerant charge from the factory has been verified to be correct on the following machines:

322C (BKJ629-Up, BPH227-Up, CAM130-Up, CBY203-Up, HEK1-Up,
SLX204-Up)
325C (BFE333-Up, G1L215-Up, M2K290-Up, S2C1-Up, S3M317-Up,
Y4P393-Up)
330C (DKY524-Up, B1K174-Up, B2L1-Up, B3M1-Up, B4N1-Up, D3C1-Up)

Illustration 1. Ducts Installed On The Lunch Box
(A) 230-4621 Duct
(B) 230-4620 Duct

The 230-4620 Duct and the 230-4621 Duct improve the airflow in the cab for the operator. The ducts snap into position. Remove the airflow louvers from the lunch box. Reinstall the louvers in the ducts. The ducts are snapped into position in order to replace the louvers on the lunch box.

Relocating the evaporator core temperature sensor may improve the vent temperature by 2.7-4.4? C (5-8? F).

Note: New software must be flashed in the 171-2545 Control Assembly or in the 233-9518 Control Assembly when the sensor is relocated. Use a 232-4958 Test Circuit Assembly in order to flash the new software.

Illustration 2. Dimensions For Temperature Sensor Location
(A) 70.0 mm (2.75 inch)
(B) 56.0 mm (2.25 inch)

Illustration 3. Pictorial View Of The Temperature Sensor Location

1. Insert the probe into the coil fins at a 45? angle. Insert the probe to a depth of 82 mm (3.2 inch). Secure a cable strap to the probe in order to make sure that the probe is not inserted deeper than the specified dimension. Refer to Illustration 2 and Illustration 3 for the correct location of the temperature sensor.

Illustration 4. Wire Routing For The Temperature Sensor

Illustration 5. Sensor Wire Routing Between The Filter Inlet And
The Main Case

Route the evaporator sensor wire between the joint of the filter inlet housing and the main case. Relocation of the evaporator sensor is completed.

Use the following procedure to reflash the controller:

1. Remove the 168-4605 Control Panel Group. Insert a thin blade screwdriver into the slot in order to release the spring-loaded clips on each end of the control panel. The panel is easily removed when the clips are released.
2. Unplug the 4-pin connector. The short harness to the control panel may require the use of a screwdriver in order to release the retainer clip on the DT connector.
3. Plug the 4-pin connector into the 232-4958 Test Circuit Assembly.
4. Turn the key for the engine start switch to the ON position. The 232-4958 Test Circuit Assembly will power up the heating and air conditioning control and the blower fan.
5. Turn the key for the engine start switch to the OFF position.
6. Unplug the 232-4958 Test Circuit Assembly. Reconnect the control panel to the 4-pin connector.
7. Turn the key for the engine start switch to the ON position.
8. Push the fan speed knob in order to power the system ON.
9. Hold down both the automatic temperature control switch and the fan speed knob. The control panel will display the parameter codes 0 through 20 and parameter code 36 on the Liquid Crystal Display (LCD) panel. Rotate the fan speed knob clockwise through the parameter codes.
10. Check parameter value "08P". The cutoff temperature for the compressor should be ?0.5? C (31? F). Reference Testing and Adjusting, RENR3899, "Troubleshooting Air Conditioner Control (Parameter Codes)".
11. Relabel the control assembly to identify it as a 231-2790 Control Assembly. The 231-2790 Control Assembly has a 08P parameter value that is set to ?0.5? C (31? F). The reprogramming is complete.

Damage to the 177-6700 Drain Tubes will decrease the performance of the air conditioner. Inspect the two drain tubes on the bottom of the HVAC unit. The drain tube should have the same appearance as drain tube (L) that is shown in Illustration 6.

The HVAC fan motor pulls air through the unit and creates a vacuum inside the case. The end of an undamaged drain tube will close and prevent hot air and debris from being pulled in the HVAC case.

The drain tube will normally hold approximately 38.1 mm (1.5 inch) of water because of the vacuum. The water will drain from the tube if an excess of 38.1 mm (1.5 inch) accumulates. The water will also drain from the tube when the fan motor is turned OFF.

Illustration 6. Bottom View Of The HVAC Unit
(K) Damaged Drain Tube
(L) Undamaged Drain Tube

Technicians in the field are replacing the 133-9014 Sensors if error code 008 was displayed on the 171-2545 Control Assembly with a date code of UAUUNM or 15Nov02. The sensor may have been functioning correctly.

If Error code 008 is displayed, measure the resistance of the 133-9014 Sensor. Submerge the sensor in ice water. The resistance should measure 66000 Ohm ⁺/_- 660 Ohm at 0? C (32? F).

If the sensor tests within the specifications, check the 171-2545 Control Assembly. If the 171-2545 Control Assembly is built before UAUUNM or 15Nov02, replace the control assembly. If the control assembly has a date code of UAUUNM or 15Nov02, and error code 008 remains after the sensor tested within specifications, check the electrical wiring between the sensor and the control assembly.

Illustration 7. 168-4605 Control Group
(J) Display panel membrane

The adhesive for the display panel membrane is improved. The new adhesive properly bonds the panel membrane to the base. If the adhesive failed, the control panel buttons may not function.

The improved adhesive for the control panel was effective with machines that were built after April 15, 2002 or:

322C (BKJ593-Up, BPH225-Up, CAM125-Up, CBY202-Up, C3R1-Up,
HEK1-Up, LAR1-Up, SLX1-Up)
325C (BFE272-Up, G1L1-Up, M2K1-Up, S2C1-Up, S3M313-Up, Y4P1-Up)
330C (DKY409-Up, B1K1-Up, B2L1-Up, B3M1-Up, B4N1-Up, D3C1-Up)

NOTE: Make sure that the operator is familiar with the function of each button and knob on the control panel. Refer to the Operation and Maintenance Manual that is appropriate for your machine. Also refer to Specifications, System Operation, Testing and Adjusting, RENR3899, Air Conditioning and Heating for additional information.

The air conditioning system may turn off when the fan speed knob is rotated. This is caused by a problem in the ON/OFF switch for the fan speed. Rotate the knob for the fan speed several times in each direction. If the system turns off unexpectedly, the control panel is defective. Replace the defective control panel. This problem is caused by a manufacturing defect. This problem will not develop or get worse over time.

Heating mode error E is produced by the resistance input value from the 133-9014 Sensor. The input value from the sensor causes the 171-2545 Control Assembly that has a date code prior to UAUUNM (15Nov02) to compute that there is an open electrical circuit and display error code 008. The heating mode error E condition will occur when the 36P parameter reading is less than -13? C (9? F). If the error E is displayed, the controller is placed in the manual operation mode. The manual operation mode allows the operator to control the fan speed by turning the fan speed knob, the air delivery by pushing the mode button, and the blend door position by turning the temperature knob. Refer to Table 1 for information on determining the date code on the control assembly.

The speed of the blower motor in the cab is limited to run on low speed until the 06P parameter temperature reads 33? C (91? F). The blower motor will ramp to high speed when the parameter is achieved. Reports from the field have documented that it may require 30 to 35 minutes in a -30? C (-22? F) ambient temperature to obtain maximum fan speed. The operator can override the automatic low fan speed by turning the fan speed knob, and then pushing the Automatic (AUT) button will cancel the low fan speed.

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