HEXA

1863 / 1906

HVAC
49
D. PRESSURE TEST USINGMANIFOLDGAUGES
This is a method where trouble is detected and re-
paired by using manifold gauge. The manifold gauge
indicates the refrigeration cycle high and low pres-
sure side pressures on the respective gauge.
NOTE
Make sure following conditions are fulfilled before
getting the correct gauge readings (after engine has
warmed –up)
Engine speed 1500rpm
A/C inlet temperature
(Ambient Temperature)
30° - 35° C (86° - 95°
F)
Blower speed High
Temperature Control Full cold
Reference value before
AC operation at both
high and low pressure
sides
5-8 kg/ cm 2 (0.5 - 0.8
MPa)
Based on the values the following conclusions can be inferred and further troubleshooting can be done.
Low Pressure side
in kg/cm2 ( M Pa)
High Pressure side
in kg/cm2 ( M Pa)
Remarks Symptoms
Possible
reasons
1.5-2.5 (0.15-0.25) 14-16 (1.37-1.57)
System pressure is
normal. Normal cooling.
AC system working
normal.
0.5-1.0 (0.05-0.1) 7-10 (0.69-0.98) Pressure low.
Insufficient cool-
ing.
1.Refrigerant quan
tity too small.
2. Gas leakage.
Vacuum 5-6 (0.5-0.6)
Refrigerant fails to
circulate.
No cooling expe-
rienced.
Clogging of AC
cycle.
Initially 1.5-2.5 (0.15
-0.25) and later vac-
uum
Initially 14-16 (1.37-
1.57)and later 7-10
(0.69-0.98)
Moisture present in
system.
Initially works
normally but later
no cooing expe-
rienced.
Freezing of expan-
sion valve due to
presence of mois-
ture.
4-6 (0.4-0.6) 7-10 (0.69-0.98)
Pressure on low
pressure side is
high and pressure
on high pressure.
.side is low.
No cooling.
Compressor Defec-
tive.