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| Illustration 1 | g00402058 |
| Fan Speed Switch (1) - The rotary switch controls the five speeds of the blower fan motor. |
| Off (2) - Turn the switch to this position in order to turn off the blower. |
Note: The cab will not be pressurized if the switch is turned to this position. The fan provides cab pressurization in order to minimize the entrance of dust.
| Low Speed (3) - Turn the switch to this position for the low fan speed. |
| Medium Speed (4) - Turn the switch to this position for a medium fan speed. |
| High Speed (5) - Turn the switch to this position for a high fan speed. |
| Purge Speed (6) - Turn the switch to this position for the purge speed. This provides maximum air flow in order to purge the operator's compartment of hot air or cold air. |
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| Illustration 2 | g00402118 |
| Temperature Control - The temperature control knob adjusts the blend of heated air and cooler air. Rotate the knob in a clockwise direction for warmer air. Rotate the knob in a counterclockwise direction for cooler air. |
This control activates the heater control valve which allows engine coolant to circulate through the heater coils. When the knob is rotated fully in the counterclockwise position, the heater control valve is completely closed and no engine coolant is circulated in the heater coils. When the knob is rotated fully in the clockwise position, the heater control valve is fully open. When you are adjusting using the control, a temperature difference may not be noticeable for several minutes. Small incremental adjustments are recommended at five minute intervals in order to avoid compensating too much for temperature.
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| Illustration 3 | g00402158 |
| Air Conditioning Switch - Push in the top portion of the switch in order to turn on the air conditioning. Push in the bottom portion of the switch in order to turn off the air conditioning. |
Operation of the Heating and Air Conditioning System
The heating and air conditioning system performs the following functions:
Heating - Turn the air conditioning switch to the OFF position. Switch on the blower fan to the desired speed. Adjust the temperature control for the desired temperature.
Cooling - Move the air conditioning switch to the ON position. Switch on the blower fan to the desired speed. Adjust the temperature control for the desired temperature. The opening and closing of the heater control valve is controlled by the temperature control. Maximum cooling is obtained while the temperature control is in the fully counterclockwise position.
Pressurizing - When heating or cooling is not desired, keep the fan on in order to pressurize the cab. Pressure inside the operator's compartment helps keep out dust. The pressure in the cab is controlled by the adjustment of the blower fan. Select a speed of the blower fan that is needed in order to provide the volume of air that is needed in order to keep out the dust. The pressure inside the cab increases as the speed of the blower fan increases.
Defogging - Operate the air conditioning and the heating simultaneously in order to aid in defrosting the windshield. The air conditioner will remove moisture from the air while the heater warms the air in the cab.
Move the air conditioning switch to the ON position. Switch on the blower fan to the desired speed. Adjust the temperature control until the windows are free of moisture.
If additional airflow is needed in certain areas, close the louvers in other locations in order to increase airflow. There are ten adjustable louvers that are provided throughout the cab.
Guidelines for Improving the Air Conditioning
The air conditioning system is designed to operate in extreme conditions. However, proper maintenance should be performed. This will ensure that the air conditioning is operating at full capacity. Observe the following guidelines in order to maximize cooling performance. The airflow in the system becomes restricted if the filter becomes plugged with dust.
- Keep the cab air filter clean. The airflow in the system becomes restricted if the filter becomes plugged with dust.
- Keep the cab tight. Be sure that the cab is sealed as tight as possible. Caulk all potential air leaks or seal all potential air leaks. This is done in order to minimize the amount of outside air that is required for cab pressurization.
- Be sure that the heater control valve is in the CLOSED position. Turning the temperature control fully in the counterclockwise position will close the heater control valve. If a leak is suspected, verify that coolant is not leaking from the heater control valve. Check for leaks by feeling the coolant return line after the air conditioner has been run for a short period of time. The coolant return line should not remain warm.