Checking Refrigerant Charge; Checking Refrigerant Pressure; Normal Pressure - Mazda MX-5 1990 Workshop Manual

AIR CONDITIONER
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4
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40 50 60
RELATIVE HUMIDITY
(%1
SIGHT GLASS
Symptom
Bubbles present in sight glass
f%
70
96U16X·103
9MUOUX-139
No bubbles present in sight glass
Immediately after air conditioner turned off,
refrigerant in sight glass stays clear
When air conditioner turned OFF, r.efrigerant
foams, and then sight glass becomes clear
05UOUX-052
10. Read the dry thermometer at the air outlet, and calculate
the difference between the inlet dry bulb and outlet dry bulb
temperatures.
11. Verify that the intersection of the relative humidity and tem-
perature difference is in the shaded lone.
Checking refrigerant charge
1. Run the engine at a fast idle.
2. Operate the air conditioner at maximum cooling for a few
minutes.
3. Determine the amount of refrigerant as shown below by ob-
serving the sight glass.
Amount of refrigerant
Action
Insufficient refrigerant Check refrigerant pressure
Too much or proper amount of Turn air conditioner off, and
refrigerant watch bubbles (Refer to Items 3
and 4)
Too much refrigerant
Check refrigerant pressure
Proper amount of refrigerant Refrigerant amount normal
9MUOUX-140
Checking refrigerant pressure
1 . Connect the manifold gauge set. (Refer to page U-28.)
2. Operate the engine at 1,500 rpm and set the air condition-
er to maximum cooling.
3. Measure the low- and high-pressure sides.
Normal pressure
Low-pressure side:
147-294 kPa (1.5-3.0 kg/cm 2 , 21-43 psi)
High-pressure side:
1,177-1,619 kPa (12.0-16.5 kg/cm2, 171-235 psi)
U-31