TM 5-2420-230-24-1
Table 19-2. A/C Sight Glass Check
Sight Glass Appearance
Refrigerant Condition
Action Required
No liquid.
No refrigerant charge.
Charge the system with R-134a
Refrigerant
Check that shut-off valves are open.
Check that the receiver-drier is not
blocked.
Good refrigerant charge.
System is normal
Clear liquid or some bubbles appear only during
cooling modes.
Bubbles in stream.
Refrigerant charge is low.
System requires refrigerant charge.
Table 19-3. High Side/Low Side Gauge Pressures at Ambient Temperature Cross-reference
Ambient Temperature
High Side Pressure
Low Side Pressure
F (C)
psi (kPa)
psi (kPa)
61 F (16 C)
123 - 174 psi (850 - 1 200 kPa)
3 - 15 psi (20 - 100 kPa)
70 F (21 C)
152 - 254 psi (1 050 - 1 750 kPa)
3 - 15 psi (20 - 100 kPa)
81 F (27 C)
181 - 276 psi (1 250 - 1 900 kPa)
3 - 15 psi (20 - 100 kPa)
90 F (32 C)
203 - 312 psi (1 400 - 2 150 kPa)
4 - 22 psi (30 - 150 kPa)
100 F (38 C)
232 - 334 psi (1 600 - 2 300 kPa)
4 - 29 psi (30 - 200 kPa)
109 F (43 C)
276 - 363 psi (1 900 - 2 500 kPa)
4 - 36 psi (30 - 250 kPa)
END OF TASK
19-10