Mazda Training manual - part 286

AIR CONDITIONING 
03 - Conducting a Performance Check

 

 

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4.  Start engine and hold at 1,500 rpm.  
 
5.  After the blower air is stabilized, read the dry-bulb thermometer.  
 

Dry-bulb temperature                        °C 

 
6.  Verify that the temperature reading is in the shaded zone.  
 

INFORMATION POINT 

Stabilized refrigerant pressures occur when maximum high side pressure remains 
the same each time the compressor cycle off. This pressure should not vary with 
the cycles. 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
(If the pressure reading is out of the specification, inspect the refrigerant system 
according to the troubleshooting chart in the Workshop Manual.) 

 

 

NOTE 

It is acceptable for outlet temperatures to be cooler than the specification. If you 
perform the test in an air-conditioned shop, your reading will not match the 
temperature/humidity zone charts. 

 

KEY POINT 

Because of individual comfort zones, customer perception of air conditioning 
performance varies. The customer may not understand the effect of humidity, solar 
gain, vehicle color, and glass area on vehicle cooling. 

 
Use this performance check to confirm that a customer’s A/C system is operating to 
manufacturer’s specifications. This check also helps guide you towards the problem 
during diagnosis. 
 

AIR CONDITIONING 
03 - Conducting a Performance Check

 

 

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Instructor Sign-Off: 
Now that you have completed this activity, you should be able to: 

 

conduct A/C performance checks 

This skill will help you accurately diagnose an A/C system. 
 
Instructor’s initials:   
 
 
 

AIR CONDITIONING 
04 - Refrigerant Charging

 

 

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Technician Name 
 
REFRIGERANT CHARGING 
 
 
Purpose: After completing this activity, you will be able to recharge refrigerant to the 
A/C system and confirm proper cooling. 
 
What you will need to complete this activity: 
 

 

Current model vehicle  

 

Workshop Manual or Body Electrical Trouble Shooting Manual 

 

R-134a Refrigerant Pressure Gauge Set (49 C061 0A0B Gas Charge Set) 

 

Vacuum Pump 

 

Electronic Leak Detector 

 

Safety Glasses 

 

NOTE 

Do not exceed the specification when charging the system with refrigerant. Doing 
so will decrease the efficiency of the air conditioner or damage the refrigeration 
cycle parts.  

 
 
Recover/Recycle R-134a Refrigerant  
 

NOTE 

Follow the device manufacturer's instructions. 

 
 
1.  Connect an R-134a recovery/recycling/recharging device to the vehicle. 
 
2.  Recover and recycle the refrigerant  
 
  
Charging Preparation 
 
1.  Install the R-134a Refrigerant 

Pressure Gauge Set. 

 
2.  Connect the vacuum pump. 
 
3. Connect the SST (49 C061 004) 

to the refrigerant tank 

 

AIR CONDITIONING 
04 - Refrigerant Charging

 

 

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4.  Place the refrigerant tank on the scale.  
 
Regular amount of refrigerant (approx. quantity)  
500 g {17.65 oz}  
 
 
Evacuation  
 
1.  Open all the valves of the pressure gauge.  
 

NOTE 

Close the SST (49 C061 001A) valve immediately after stopping the vacuum pump. 
If the valve is left open, the vacuum pump oil will flow back into the refrigeration 
cycle and cause a decrease in the efficiency of the air conditioner. 

 
 
2. Start the vacuum pump and let it operate for 15 min. 
 
3. Verify that high- and low-pressure side readings are at -101 kPa {-760 mmHg, -
29.9 inHg}. Close each valve. 
 
 
Air-tightness Check  
 
1.  Stop the vacuum pump and wait for 5 min.  
 
2.  Check the high- and low-pressure side readings of the gauge.  
(If the reading has changed, inspect for leakage and go to Evacuation.)  
 
 
Charging New R-134a Refrigerant  
 
1.  Open the valve of the refrigerant tank. 
 
2.  Weigh the refrigerant tank and record it.  
 

Weight                                g (oz) 

 

NOTE 

If the refrigerant system is charged with a large amount of refrigerant when 
inspecting for gas leakage, and if any leakage should occur, the refrigerant will be 
released into the atmosphere. In order to prevent the accidental release of 
refrigerant that can destroy the ozone layer in the stratosphere, follow the proper 
procedures and charge with only a small amount of refrigerant when inspecting for 
gas leakage.