SPOOL-RELIEF 7T6420 - Caterpillar

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.
Start the engine and run the engine at high idle.
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Press the top of the air conditioner switch.
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Set the air conditioner switch knob (1) to the setting for maximum cooling. Set the fan speed switch knob (2) to HIGH .
Allow the air conditioning system to stabilize for two minutes.
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Open the engine access door on the right side of the machine.
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To check the system for refrigerant, feel suction line (1) and discharge line (2) .If the system contains refrigerant, the discharge line will be warmer than the suction line.If the system does not contain refrigerant or the system is very low on refrigerant, poor cooling will result.