Mazda Training manual — part 285

AIR CONDITIONING
02 - Locating A/C Protection Devices

Activity02-2

TC070-15-01H

Pressure Relief Valve
1. Where is this device located?


2. At what pressure will you expect the pressure relief valve to discharge refrigerant

to the atmosphere?

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

locate A/C system protection devices

explain the function of protection devices

This skill will help you evaluate protection devices for correct operation.

Instructor’s initials:

AIR CONDITIONING
03 - Conducting a Performance Check

SG03-1

TC070-15-01H

Technician Name

CONDUCTING A PERFORMANCE CHECK

Purpose: In this activity, you will diagnose a vehicle’s air conditioning system.

A performance check is the basis of air conditioning diagnosis. All diagnostic routines
should begin and end with this test to determine if the system is performing to
specifications. It is thorough and easy to perform.

What you will need to complete this activity:

Current model vehicle

Workshop Manual or Body Electrical Trouble Shooting Manual

Thermometer

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

Safety Glasses

NOTE

Humidity and temperature have an effect on the outcome of this test.

Function Check

NOTE

During the following tests, monitor instrument panel gauges and warning lights for
out of specification readings.

1. Set hand brake and place gear selector in Park (ATX) or Neutral (MTX).

2. Keep hood open throughout the test to maximize airflow through the radiator and

condenser.

3. With engine running, select all the blower fan speeds.

Does the fan speed change? Yes No

Are all speeds available? Yes No
(If no, repair according to workshop manual directions.)

4. Operate mode control to all positions and confirm that sufficient airflow is at each

position.

Does the airflow change according to the position of the mode control indication
on the dash? Yes No
(If no, repair according to workshop manual directions.)

AIR CONDITIONING
03 - Conducting a Performance Check

SG03-2

TC070-15-01H

5. Operate temperature select control throughout its range and confirm that the

airflow temperature matches the setting. Start with the control in the coolest
setting and slowly increase temperature to highest setting, then back to original
setting. Does the temperature match the control setting? Yes No

(If no, repair according to workshop manual directions.)

6. Turn off engine.

INFORMATION POINT

A small temperature difference between the setting and the actual duct
temperature is normal. The duct temperature will usually be cooler than the interior
temperature. This is because the evaporator is concentrated in the small area of
the duct very close to the evaporator.

Gauge Installation

Install R-134a Refrigerant Pressure Gauge Set according to the workshop manual.

a. Confirm that high and low valves are closed.
b. Remove caps from charging ports.
c. Connect the quick disconnect couples to vehicle charging ports and open line

valves.

NOTE

Support A/C lines during coupling. Excessive pressure can cause damage to
unsupported lines.

Refrigerant Pressure Check

2. Place a dry-bulb thermometer in the driver-side center ventilator outlet.

3. Close all doors and windows.

4. Set A/C controls for maximum cooling with:

a. temperature to full cold
b. airflow to face/vent to Vent
c. fresh/recirculate control to Recirculate
d. activate compressor with fan speed high

5. Start engine and hold at 1,500 rpm.

AIR CONDITIONING
03 - Conducting a Performance Check

SG03-3

TC070-15-01H

6. Measure the ambient temperature and high- and low- pressure side reading of the

pressure gauge.

Ambient temperature °C

High pressure psi / Low pressure psi
Ambient temperature

7. Verify that the intersection of the pressure reading of the pressure gauge and

ambient temperature is in the shaded zone.

Performance Check

1. Place a dry-bulb thermometer in the driver-side center ventilator outlet.

2. Close all doors and windows.

3. Set A/C controls for maximum cooling with:

a. temperature to full cold
b. airflow to face/vent to Vent
c. fresh/recirculate control to Recirculate
d. activate compressor with fan speed high