2004 ISUZU TF SERIES light

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ISUZU TF SERIES 2004 Workshop Manual HEATER AND AIR CONDITIONING 1-35
Reading Sight Glass

High and low
pressure pipe
temperature The high pressure
pipe is hot and the
low pressure pipe
is cold. There is a
distinct difference

HEATER AND AIR CONDITIONING 1-35
Reading Sight Glass

High and low
pressure pipe
temperature The high pressure
pipe is hot and the
low pressure pipe
is cold. There is a
distinct difference
in temperature
between them. The high pressure
pipe is warm and
the low pressure
pipe is cool. There
is no great
difference in
temperature
between them. There is little
difference in
temperature
between the high
pressure pipe and
the low pressure
pipe. The high pressure
pipe is hot and the
low pressure pipe
is slightly warm.
There is a
difference in
temperature
between them.
Sight glass
condition Almost transparent.
A flow of bubbles
can be seen, but
they disappear
when the throttle is
opened.

A flow of bubbles
always can be
seen. It appears
sometimes
transparent, and
sometimes frothy.
Something like fog
faintly can be seen.
Evan at idle with
the fan at "HI" (with
the window fully
open), the bubbles
cannot be seen.

Air conditioning
cycle condition
OK NG
(Not enough
refrigerant) NG
(Almost no
refrigerant) NG
(Too much
refrigerant)

The sight glass provides accurate diagnosis only under the following conditions.
If the vehicle can be tested under these conditions, check the sight glass appearance and compare to the chart.
* Engine speed Idling
* A/C switch "ON"
* Blower fan operating at highest speed
* Air source selector lever at "RECIRC"
* Temperature control knob at coldest position
* Ambient temperature below 35
C (95
F) and humidity below 70% (See NOTE 1)
* High side pressure less than 1470 kPa (15 kg/cm
2 / 213 PSI) (See NOTE 2)

NOTE 1
If the vehicle cannot be moved to a testing location that meets these specifications, then the sight glass cannot be
used for diagnosis. You must discharge and recover the refrigerant, then recharge the system with the specified
amount of refrigerant. Then continue checking the system performance.

NOTE 2
If the high side pressure is greater than stated, the sight glass cannot be used for diagnosis. You must discharge
and recover the refrigerant, then recharge the system with the specified amount of refrigerant. Then continue
checking system performance.