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How to Discharge an Bus Air Conditioner

Aug 18, 2017
Most buses are equipped with bus air conditioning system to keep the passenger's compartment cool and comfortable. These bus air conditioner units also make a vehicle safer to operate, because they work with the buses' defroster to dehumidify the interior and prevent window fogging and icing. The near-universal presence of bus air conditioning system presents a good business opportunity for repair facilities that wish to add on to their customer base and provide a valuable service. An investment in bus air conditioner units service machine and obtaining an Environmental Protection Agency certification will have you servicing rooftop air conditioner for bus quickly using these steps.
Things You'll Need
Bus Air conditioning System service machine
Refrigerant purity tool
Supply of HC-134A
EPA certification
Step 1: Determine that the bus air conditioning system contains pure refrigerant before discharging, or evacuating the system of refrigerant.
Use a refrigerant purity indication tool for this task. This is an electronic tool that connects to the bus air conditioning system service port and reads a small sample of refrigerant. Although most automotive refrigerant is pure, some facilities not qualified to work with bus air conditioner units may have added refrigerant a contaminated or even flammable system. Recover contaminated refrigerant in a separate container so that it is not re-used. Use a filter in your recovery equipment designed to separate sealers put in the system to stop leaks. These materials can damage recovery equipment.
Step 2: Connect the bus air conditioner units recovery and recharge machine to the bus air conditioner units service ports.
The low pressure side connector is indicated with a blue cap, and a red cap covers the high pressure side. The hoses on the machine are color-coded the same way. Connect the hoses to the corresponding ports. Note any pressure readings in the system on the recovery machine's gauges.

PD-03 bus air conditioner
PHOTO: The picture of Guchen PD-03 rooftop bus air conditioner applies on the 7 meter length Fuso-Minibus for university students and teachers transpiration in Pakistan.
Step 3: Start the evacuation process of bus air conditioner units.
Many bus air conditioning system service machines are automatic, and you just have to push one button or turn a knob. The pump inside of the machine will start, moving the refrigerant into the machine's internal tank. The pressure gauges will drop as the refrigerant is recovered.
Step 4: Allow the bus air conditioning system service machine to draw the system down so that a vacuum exists, as shown on the gauges.
When the gauges reach zero, the recovery process from the vehicle is complete, and there is no more refrigerant in the system.
Step 5: Allow the system to hold a vacuum for at least 10 minutes.
If the vehicle is unable to maintain a vacuum on the gauge, the bus air conditioning system has a leak, which must be repaired before the system is recharged with refrigerant. Program the machine to dispense the amount of refrigerant required by the vehicle's system. This is usually indicated on a sticker under the hood. Start the charging process by setting the machine to start. When the process is finished, check the rooftop air conditioner for bus for correct function.
Tips & Warnings
① If the rooftop air conditioner for bus is cold, but not as cold as it should be, you can add a small amount of refrigerant using cans sold at auto parts stores. Some of these cans also include a fluorescent dye, which will show up as a bright green color when illuminated by a special lamp. This helps show where the system is leaking.
② Do not discharge the system by loosening a hose fitting or removing a hose. This is illegal, and refrigerant fumes can be harmful if inhaled. Do not service a bus air conditioning system unless you are EPA certified to do so.
With the development of economy and the enhancement of people's health consciousness and educational level, the public and government pay more attention to environmental protection. And they are seeking for cleaner energy to replace fuel. 
Guchen Company always adheres to the values of "Energy, synergy and innovation" , and continuously works on creating a comfortable, satisfactory, healthy, safe and clean products. So Guchen full electric bus air conditioner gets high praises at home and abroad when it hits the market. Guchen electric air conditioner units for bus currently have following four models,
full electric bus air conditioner
ED-03 Full Electric Bus Air Conditioner--- Apply for 6-7 meter bus 
ES-05 Full Electric Bus Air Conditioner--- Apply for 8.5-9 meter bus
ES-06 Electric Air Conditioner Units for Bus--- Apply for 10-12 meter bus
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