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A/C PERFORMANCE TESTING. CHAPTER 3. Page 50-53. PREPARATION. Develop a consistent routine. Use Common Sense Approach Consult Service Manuals Cleanliness Safety Windows Down . VISUAL INSPECTION. Inspect under hood for SIGNS OF LEAKAGE/HOSE CONDITION
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A/C PERFORMANCE TESTING CHAPTER 3 Page 50-53
PREPARATION • Develop a consistent routine. • Use Common Sense Approach • Consult Service Manuals • Cleanliness • Safety • Windows Down
VISUAL INSPECTION • Inspect under hood for SIGNS OF LEAKAGE/HOSE CONDITION • Inspect CONDENSER for signs of damage • Inspect COMPRESSOR BELT condition • Inspect COOLING SYSTEM condition • Inspect A/C Controls Function
STABILIZE SYSTEM • Make sure Manifold Gauge set valves are shut before hooking up to system • Connect to the system • Start Engine and Run 1500 - 1700 rpm • Let Engine get to full operation temp • Turn on A/C and set blower to high and set A/C system to max A/C • Put thermometer in A/C duct inside car.
Manifold Gauge Set • A Manifold Gauge Set • 3 Pressure Hoses • Low Side (blue hose) Compound Gauge - vacuum to approx. 250 PSI • High Side (red hose) Gauge - 0 to approx.. 500 PSI • Two separate Hand Valves • Some Gauges can be calibrated
Manifold Gauge Set Operation • Pressure Check of System - both valves closed • Charging with Refrigerant - Low side open • Evacuation - Both valves open Page 5L
GAUGE PRESSURE CHECK • Low side average: 20 to 30 PSI • High side average: 160 to 220 PSI • High side “rule of thumb”: Add 100 PSI to ambient temperature example: It’s 80 degrees outside, add 100 PSI. approximate high side pressure should be 180 PSI • Discharge temperature should be within specified range for system. (35 to 50 degree)
“HAND FEEL CHECK” • RULE OF THUMB: • All high side hoses and components should be warm to touch • All low side hoses and components should be cool to the touch • Note condition of TXV or FOT • Is is frosted on inlet side = bad valve or orifice or moisture in system
QUICK “FEEL” CHECK • If ambient temp above 70 degrees F • Engine warm and at idle • Max A/C and High Blower • feel evaporator inlet pipe and accumulator • Both same temp and cooler than ambient - OK • inlet pipe cooler than accumulator - Low charge • Inlet pipe warmer than evap outlet - overcharge
Hand Tools You Will Use • Thermometer • Leak Detector • Vacuum Pump • Snap Ring Pliers • Seal Installers/Removers • Safety Glasses • Can Taps and Hose Adapters (pg.. 49L) • Shut Off Valve Service Hose (pg. 46L)
TEST CONTROL DEVICES • Refer to Service Manual • Relative Humidity • Pg. 8C and 53L • Make sure if FOT system that clutch is cycling (norm temp) • Can test Expansion Valve if accessible • Condenser Fan Operation