Checking Of Refrigeration System With Manifold Gauge - Toyota Celica Supra 1986 Service And Repair Manual

AC·4
AIR CONDITIONING SYSTEM -Troubleshooting
Checking of Refrigeration Syst em
with Manifold Gauge
This is a method in which the trouble is located by using a
manifold gauge.
Read the manifold gauge pressure with the following
establ ished conditions:
(a) Temperature at the air inlet is
30 - 35• c (86 -
gs•Fl
(b) Engine running at 2,000 rpm
(c) Blower speed set at h igh
(d) AIC switch ON
(e) Temperature control lever set at cool
NOTE : It should be noted that the gauge indications may
vary sl ightly due t o ambient temperature conditions.
1.
NORMALLY FUNCTIONING REFRIGERATION
SYSTEM
Gauge reading:
Low pressure side 1.5 - 2 .0
kg/em'
""""' (21 - 28
psi,
147 - 196 kPa)
L . . - - - - - - - - - - - --"=..
High pressure side 14.5 - 15.0 kg/em'
Symptom seen in
refr igilration system
During operation. prtmure
at low pressure s ide some•
times become$ a vacuum
and sometimes normal
(206 - 213
psi,
1,422 -1,471 kPal
2. MOIST URE PRESENT IN REFR IGERATION SYSTEM
Condition: Periodically cools and then fails to cool
.....
Probable cause
Oi&gnc>Si$ Remedy
Moisture entered in refrig• Drier in oversaturated state (11 Replace receiver and
eration system freezes at l
.
drier
e)Cp.all$ion valve
Ofif~
and
Moisture in refrigeration
(21
Remove moisture in
temporarily stops cycle, but
wstem freezes at ex- pansion cycle t hrough repeated
normal nate is restored afttr
valve orifice and blocks vacuum pvrging
a t ime when the ice melts-
c irculat ion of refrigerant
(31 Charge
n-ew refrigerant to
proper amount