Air Conditioning and Heating R-12 All Caterpillar Machines – Refrigerant System – Charge

------ WARNING! ------

Personal injury can result from contact with refrigerant.

This system is under pressure at all times, even if the engine is not running. Heat should never be applied to a charged system.

Contact with refrigerant can cause frost bite. Keep face and hands away to help prevent injury.

Protective goggles must always be worn when refrigerant lines are opened, even if the gauges indicate the system is empty of refrigerant.

Always use caution when a fitting is removed. Slowly loosen the fitting. If the system is still under pressure, evacuate the system recovering the refrigerant before removing the fitting.

Personal injury or death can result from inhaling refrigerant through a lit cigarette.

Inhaling air conditioner refrigerant gas through a lit cigarette or other smoking method or inhaling fumes released from a flame contacting air conditioner refrigerant gas, can cause bodily harm or death.

Do not smoke when servicing air conditioners or wherever refrigerant gas may be present.

Before any checks of the air conditioning and heating system are made, move the machine to a smooth horizontal surface. Lower all implements to the ground. Make sure the transmission is in neutral or park and that the parking brake is engaged. Keep all other personnel away from the machine or where they can be seen.

----------------------

Table 1
Required Tools    
Part Number     Part Description     Quantity    
4C-4874     Heater Blanket As     1    

Relationship Between Temperature and Pressure (R-12 Refrigerant)

Table 2 can be used in order to determine the pressure level and contamination level of a container of refrigerant. Table 2 can also be used for an air conditioning system that is not operating. This same system must be stabilized to the ambient temperature. In order to stabilize an air conditioning system at the ambient temperature, the machine must not operate for 10 to 12 hours. The machine must not be stored in direct sunlight.

If the pressure that is measured at any specific temperature does not match the pressure that is given in the chart, the following problems may exist:

  • Contaminants in the system

  • Incorrect refrigerant

  • Incorrect refrigerant charge

Table 2
Relationship Between Temperature and Pressure (R-12 Refrigerant)    
Temperature °C (°F)     Pressure kPa (psi) (1)    
-18 °C (0.0 °F)     63 kPa (9.1 psi)    
-17° C (2.0 °F)     70 kPa (10.1 psi)    
-16 °C (4.0 °F)     77 kPa (11.2 psi)    
-14 °C (6.0 °F)     85 kPa (12.3 psi)    
-13 °C (8.0 °F)     92 kPa (13.4 psi)    
-12 °C (10.0 °F)     101 kPa (14.6 psi)    
-11 °C (12.0 °F)     109 kPa (15.8 psi)    
-10 °C (14.0 °F)     118 kPa (17.1 psi)    
-9 °C (16.0 °F)     126 kPa (18.3 psi)    
-8 °C (18.0 °F)     136 kPa (19.7 psi)    
-7 °C (20.0 °F)     145 kPa (21.0 psi)    
-6 °C (21.0 °F)     150 kPa (21.7 psi)    
-6 °C (22.0 °F)     154 kPa (22.4 psi)    
-5 °C (23.0 °F)     159 kPa (23.1 psi)    
-4 °C (24.0 °F)     164 kPa (23.8 psi)    
-4 °C (25.0 °F)     170 kPa (24.6 psi)    
-3 °C (26.0 °F)     174 kPa (25.3 psi)    
-3 °C (27.0 °F)     180 kPa (26.1 psi)    
-2 °C (28.0 °F)     185 kPa (26.8 psi)    
-2 °C (29.0 °F)     190 kPa (27.6 psi)    
-1 °C (30.0 °F)     196 kPa (28.4 psi)    
-1 °C (31.0 °F)     201 kPa (29.2 psi)    
0 °C (32.0 °F)     207 kPa (30.0 psi)    
1 °C (33.0 °F)     213 kPa (30.9 psi)    
1 °C (34.0 °F)     219 kPa (31.7 psi)    
2 °C (35.0 °F)     224 kPa (32.5 psi)    
2 °C (36.0 °F)     230 kPa (33.4 psi)    
3 °C (37.0 °F)     237 kPa (34.3 psi)    
3 °C (38.0 °F)     242 kPa (35.1 psi)    
4 °C (39.0 °F)     248 kPa (36.0 psi)    
4 °C (40.0 °F)     254 kPa (36.9 psi)    
5 °C (41.0 °F)     261 kPa (37.9 psi)    
6 °C (42.0 °F)     268 kPa (38.8 psi)    
6 °C (43.0 °F)     274 kPa (39.7 psi)    
7 °C (44.0 °F)     281 kPa (40.7 psi)    
7 °C (45.0 °F)     288 kPa (41.7 psi)    
8 °C (46.0 °F)     294 kPa (42.6 psi)    
8 °C (47.0 °F)     301 kPa (43.6 psi)    
9 °C (48.0 °F)     308 kPa (44.6 psi)    
9 °C (49.0 °F)     314 kPa (45.6 psi)    
10 °C (50.0 °F)     321 kPa (46.6 psi)    
11 °C (51.0 °F)     330 kPa (47.8 psi)    
11 °C (52.0 °F)     336 kPa (48.7 psi)    
12 °C (53.0 °F)     343 kPa (49.8 psi)    
12 °C (54.0 °F)     351 kPa (50.9 psi)    
13 °C (55.0 °F)     359 kPa (52.0 psi)    
13 °C (56.0 °F)     366 kPa (53.1 psi)    
14 °C (57.0 °F)     382 kPa (55.4 psi)    
14 °C (58.0 °F)     390 kPa (56.6 psi)    
15 °C (59.0 °F)     394 kPa (57.1 psi)    
16 °C (60.0 °F)     398 kPa (57.7 psi)    
16 °C (61.0 °F)     406 kPa (58.9 psi)    
17 °C (62.0 °F)     414 kPa (60.0 psi)    
17 °C (63.0 °F)     423 kPa (61.3 psi)    
18 °C (64.0 °F)     431 kPa (62.5 psi)    
18 °C (65.0 °F)     439 kPa (63.7 psi)    
19 °C (66.0 °F)     448 kPa (64.9 psi)    
19 °C (67.0 °F)     456 kPa (66.2 psi)    
20 °C (68.0 °F)     465 kPa (67.5 psi)    
21 °C (69.0 °F)     474 kPa (68.8 psi)    
21 °C (70.0 °F)     483 kPa (70.1 psi)    
22 °C (71.0 °F)     492 kPa (71.4 psi)    
22 °C (72.0 °F)     502 kPa (72.8 psi)    
23 °C (73.0 °F)     512 kPa (74.2 psi)    
23 °C (74.0 °F)     521 kPa (75.5 psi)    
24 °C (75.0 °F)     530 kPa (76.9 psi)    
24 °C (76.0 °F)     540 kPa (78.3 psi)    
25 °C (77.0 °F)     546 kPa (79.2 psi)    
26 °C (78.0 °F)     559 kPa (81.1 psi)    
26 °C (79.0 °F)     569 kPa (82.5 psi)    
27 °C (80.0 °F)     579 kPa (84.0 psi)    
27 °C (81.0 °F)     590 kPa (85.5 psi)    
28 °C (82.0 °F)     600 kPa (87.0 psi)    
28 °C (83.0 °F)     610 kPa (88.5 psi)    
29 °C (84.0 °F)     621 kPa (90.1 psi)    
29 °C (85.0 °F)     632 kPa (91.7 psi)    
30 °C (86.0 °F)     643 kPa (93.2 psi)    
31 °C (87.0 °F)     654 kPa (94.8 psi)    
31 °C (88.0 °F)     665 kPa (96.4 psi)    
32 °C (89.0 °F)     676 kPa (98.0 psi)    
32 °C (90.0 °F)     687 kPa (99.6 psi)    
33 °C (91.0 °F)     698 kPa (101.3 psi)    
33 °C (92.0 °F)     710 kPa (103.0 psi)    
34 °C (93.0 °F)     721 kPa (104.6 psi)    
34 °C (94.0 °F)     733 kPa (106.3 psi)    
35 °C (95.0 °F)     745 kPa (108.1 psi)    
36 °C (96.0 °F)     757 kPa (109.8 psi)    
36 °C (97.0 °F)     769 kPa (111.5 psi)    
37 °C (98.0 °F)     781 kPa (113.3 psi)    
37 °C (99.0 °F)     794 kPa (115.1 psi)    
38 °C (100.0 °F)     806 kPa (116.9 psi)    
38 °C (101.0 °F)     819 kPa (118.8 psi)    
39 °C (102.0 °F)     832 kPa (120.6 psi)    
39 °C (103.0 °F)     844 kPa (122.4 psi)    
40 °C (104.0 °F)     857 kPa (124.3 psi)    
41 °C (105.0 °F)     870 kPa (126.2 psi)    
41 °C (106.0 °F)     883 kPa (128.1 psi)    
42 °C (107.0 °F)     896 kPa (130.0 psi)    
42 °C (108.0 °F)     911 kPa (132.1 psi)    
43 °C (109.0 °F)     932 kPa (135.1 psi)    
43 °C (110.0 °F)     938 kPa (136.0 psi)    
44 °C (111.0 °F)     952 kPa (138.0 psi)    
44 °C (112.0 °F)     966 kPa (140.1 psi)    
45 °C (113.0 °F)     980 kPa (142.1 psi)    
46 °C (114.0 °F)     994 kPa (144.2 psi)    
46 °C (115.0 °F)     1009 kPa (146.3 psi)    
47 °C (116.0 °F)     1023 kPa (148.4 psi)    
47 °C (117 °F)     1043 kPa (151.2 psi)    
48 °C (118.0 °F)     1053 kPa (152.7 psi)    
48 °C (119.0 °F)     1068 kPa (154.9 psi)    
49 °C (120.0 °F)     1173 kPa (170.2 psi)    
49 °C (121.0 °F)     1083 kPa (157.1 psi)    
50 °C (122.0 °F)     1098 kPa (159.3 psi)    
51 °C (123.0 °F)     1114 kPa (161.5 psi)    
51 °C (124.0 °F)     1145 kPa (166.1 psi)    
52 °C (125.0 °F)     1161 kPa (168.4 psi)    
52 °C (126.0 °F)     1177 kPa (170.7 psi)    
53 °C (127.0 °F)     1194 kPa (173.1 psi)    
53 °C (128.0 °F)     1209 kPa (175.4 psi)    
54 °C (129.0 °F)     1226 kPa (177.0 psi)    
54 °C (130.0 °F)     1256 kPa (182.2 psi)    
55 °C (131.0 °F)     1259 kPa (182.6 psi)    
56 °C (132.0 °F)     1276 kPa (185.1 psi)    
56 °C (133.0 °F)     1294 kPa (187.6 psi)    
57 °C (134.0 °F)     1311 kPa (190.1 psi)    
( 1 ) All pressures in this table are gauge pressures.

Charging the System

Note: An accurate refrigerant charge may only be determined by weight. Pressures can not be used in order to determine if the air conditioning system is correctly charged. Do not add or remove part of the refrigerant.

Note: Never charge liquid or gas through the discharge side (high side) of the system when the engine is in operation.

Note: Refer to the Specifications, “System Capacities for Refrigerant” section for the proper capacity. Also, refer to the Service Manual, SENR3334, “Identifying the Air Conditioning System” section.

Note: If the engine is running, charge the system with refrigerant gas through the low pressure side. Never charge liquid refrigerant through the suction side (low pressure side) of the air conditioning system. If liquid refrigerant is charged through the suction side (low pressure side), the compressor will become damaged. If the engine is not running, charge with liquid or gas through the high pressure side.

Note: Before you charge the system, these important items should be checked.

  1. Condenser and evaporator

    • Inspect the condenser and inspect the evaporator for foreign material that would inhibit air flow such as dirt, insects, plastic bags, etc.

    • With condensers that are mounted on the roof and with remote mounted condensers, always check that both fan motors are running. Check for restrictions. A clean condenser will lead to improved life for the compressor.

  1. Check for a loose belt on the compressor.
  1. Clean the fresh air filter and clean the recirculation filter.
  1. Check the moisture indicator, if equipped. The moisture indicator is located on either the receiver-dryer or the in-line dryer. If the moisture indicator is pink or white, there is moisture in the system. Replace the receiver-dryer. Refer to Disassembly and Assembly, SENR3334, “Receiver-Dryer – Remove and Install”.
  1. Check the condensate tube on the evaporator. Make sure that the tube is not plugged and that the valve is properly in place.

    Note: Before an accurate reading for moisture can be attained, a new receiver-dryer requires 2 to 3 hours of operation.

    Refer to the Troubleshooting, “Machine Preparation for Troubleshooting” section in testing and adjusting before service work is performed on the air conditioning system.

    Note: The preferred method for charging the air conditioning system is listed below.

    • Recover the refrigerant.

    • Evacuate the system.

    • Charge the system with the correct amount of refrigerant. Measure the refrigerant by weight.

    Note: After the system has been recovered and the system has been evacuated, the system needs to be charged with the correct amount of refrigerant. Measure the refrigerant by weight. Refer to the Specifications, “System Capacities for Refrigerant” section for the proper capacity. Also, refer to the Service Manual, SENR3334, “Identifying the Air Conditioning System” section.

Complete Charge of the System from a Refrigerant Tank with a Scale

The use of a refrigerant tank and a scale is necessary in order to charge the system. Use the procedure that follows to charge the system.

Note: When you charge the system with a liquid, ensure that the engine is not running.

  1. In order to find the refrigerant capacity for the system that needs a refrigerant charge, refer to the Specifications, “System Capacities for Refrigerant” section. Also, refer to the Service Manual, SENR3334, “Identifying the Air Conditioning System” section.



    Illustration 1 g00889250

    (1) Low pressure valve

    (2) High pressure valve

    (3) Manifold gauge set

    (4) Valve on top of refrigerant tank

    (5) Charging hose

    (6) Low pressure hose

    (7) High pressure hose

    (8) Service valve (discharge)

    (9) Service valve (suction)

    (10) Refrigerant tank

    (11) Scale

    (E) Vapor

    (F) Liquid

  1. Hand tighten charging hose (5) from the manifold gauge set directly to the valve (4) on refrigerant tank (10). Open the valve (4) on top of refrigerant tank (10). This allows the flow of refrigerant through the charging hose (5) to the manifold gauge set (3) .
  1. Loosen the charging hose (5) at the manifold gauge set (3) for two to three seconds. Then tighten the connection. This procedure will purge the air from the line.
  1. Place the refrigerant tank (10) on the scale (11) so that the valve (4) is at the bottom. Check the weight of the tank.
  1. Open the high pressure valve (2) on the manifold gauge set (3). This action allows the liquid refrigerant to charge the system through the high pressure side of the compressor.
  1. Check the weight of the refrigerant tank (10) often. The weight will decrease as the refrigerant leaves the tank and the refrigerant enters the system. When the required amount of refrigerant (system capacity) has entered the system, close the valve (4) and close the high pressure valve (2). Closing the valves stops the flow of the refrigerant.

    Note: A heater blanket may be required when you charge an air conditioning system with a partially full refrigerant tank.

  1. In order to ensure correct system operation, disconnect charging hose (5) and conduct a performance check.

Adding Additional Refrigerant to an Air Conditioning System that Has a Low Charge


NOTICE

Failure to properly follow the procedure may cause compressor failure. The procedure that follows is not the preferred method for charging an air conditioning system. The preferred method of measuring the refrigerant is by weight.


Note: The procedure that follows is applicable only if the inlet air temperature at the condenser is above 21 °C (70.0 °F). The procedure may be repeated a second time in order to achieve the proper charge with this method.


NOTICE

If the system has no refrigerant, evacuate the system before charging the system. The refrigerant charge should be measured by weight.





    Illustration 2 g00896707

    (1) Low pressure valve

    (2) High pressure valve

    (3) Manifold gauge set

    (4) Valve on top of refrigerant tank

    (5) Charging hose

    (6) Low pressure hose

    (7) High pressure hose

    (8) Service valve (discharge)

    (9) Service valve (suction)

    (A) Vapor

    (B) Liquid

  1. Connect the manifold gauge set to the discharge and service ports on the compressor. Refer to Testing and Adjusting, “Manifold Gauge Set (Refrigerant) – Install”.
  1. Make sure that the low pressure valve (1) and the high pressure valve (2) are closed on the manifold gauge set (3) .
  1. Turn the valve (4) on the tank counterclockwise. This action will release the refrigerant to the charging hose (5) .

    Note: Make sure that the cylinder of refrigerant is in the upright position. This allows the refrigerant to enter the system as a gas.

  1. Loosen the hose connection on the charging hose (5) at the manifold gauge set for two to three seconds. Then tighten the connection. This action allows air to be released from the charging hose (5) .
  1. Remove high pressure hose (7) from service valve (8). Quickly place a clean rag over the opening in service valve (8). Open discharge valve (2) about one half turn for two or three seconds. Remove the rag and attach high pressure hose (7) and quickly close discharge valve (2). Repeat the procedure for the low pressure hose (6) .
  1. Start the engine and run the engine at 1300 to 1400 rpm.
  1. Position the temperature control knob to the MAX position, and position the fan switch to the HI position.

    Note: If the machine is equipped with an expansion valve system, refer to “Expansion Valve System”. If the machine is equipped with an Orifice Tube system, refer to “Orifice Tube System”.

Expansion Valve System

  1. Identify the capacity of the receiver-dryer. The part number is printed on the receiver-dryer.

    Table 3
    Receiver-Dryer Capacities    
    Part Number     Capacity    
    9D-6888     0.5 kg (1 lb)    
    8T-8642     0.9 kg (2 lb)    
    5V-5698     0.9 kg (2 lb)    
    9W-0549     0.9 kg (2 lb)    
    106-3532     0.9 kg (2 lb)    
    106-5534     0.9 kg (2 lb)    
    106-5533     0.9 kg (2 lb)    

  1. Open suction valve (1) in order to release the refrigerant into low pressure hose (6). Slowly add refrigerant until the bubbles disappear in the sight glass. After the bubbles disappear, add the proper amount of refrigerant for the receiver-dryer on your machine.

    Note: A heater blanket may be required when you charge an air conditioning system with a partially full refrigerant tank.

  1. Close suction valve (1) in order to prevent the flow of additional refrigerant to the compressor.

    Note: If suction valve (1) is opened completely, the low pressure gauge reading will appear excessively high until the system becomes fully charged.

  1. If the pressure on the suction side becomes too high, the system is overcharged. If the discharge pressure becomes too high, the system is overcharged. Close the valve on the refrigerant tank completely. Closing the valve will shut off the flow of refrigerant to the charging hose (5). Shut down the engine. Recover the charge and evacuate the system. Recharge the system to the correct charge by weight.
  1. The gauge reading for low pressure valve (1) should be within the normal range after you charge the system. The gauge reading for high pressure valve (2) should be within the normal range after you charge the system. If the gauge readings are within normal range, the system is properly charged. Close the valve on the refrigerant tank completely. Move the air conditioning controls to the OFF position and stop the engine.

Orifice Tube System

  1. Open suction valve (1) in order to release the refrigerant into low pressure hose (6). Slowly add refrigerant until the outlet of the evaporator coil feels as cold to the touch as the inlet of the evaporator coil.

    Note: A heater blanket may be required when you charge an air conditioning system with a partially full refrigerant tank.

  1. Close suction valve (1) in order to prevent the flow of additional refrigerant to the compressor.

    Note: If suction valve (1) is opened completely, the low pressure gauge reading will appear excessively high until the system becomes fully charged.

  1. If the pressure on the suction side becomes too high, the system is overcharged. If the discharge pressure becomes too high, the system is overcharged. Close low pressure valve (1) completely. Check the receiver-dryer sight glass. Feel the high pressure lines and feel the low pressure lines for temperature variations. Check the temperature of the air flow from the evaporator to check for an overcharged condition. Recover the charge and evacuate the system. Recharge the system to the correct charge by weight.
  1. If indications of an overcharge are present, close the valve on the refrigerant tank completely. Closing the valve will shut off the flow of refrigerant to the charging hose (5). Shut down the engine. Recover the charge and evacuate the system. Recharge the system to the correct charge by weight.
  1. The gauge reading for low pressure valve (1) should be within the normal range after you charge the system. The gauge reading for high pressure valve (2) should be within the normal range after you charge the system. If the gauge readings are within normal range, the system is properly charged. Close the valve on the refrigerant tank completely. Move the air conditioning controls to the OFF position and stop the engine.
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