Owner's Manual

MTC-62
INSUFFICIENT COOLING
HIGH-PRESSURE SIDE IS TOO LOW AND LOW-PRESSURE SIDE IS TOO HIGH.
BOTH HIGH- AND LOW-PRESSURE SIDES ARE TOO LOW.
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too low and
low-pressure side is too high.
High and low-pressure sides
become equal soon after
compressor operation stops.
Compressor pressure opera-
tion is improper.
↓
Damaged inside compressor
packings
Replace compressor.
No temperature difference
between high and low-pres-
sure sides
Compressor pressure opera-
tion is improper.
↓
Damaged inside compressor
packings.
Replace compressor.
AC356A
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure sides
are too low.
● There is a big temperature
difference between receiver
drier outlet and inlet. Outlet
temperature is extremely
low.
● Liquid tank inlet and expan-
sion valve are frosted.
Compressor discharge capac-
ity does not change. (Com-
pressor stroke is set at
maximum.)
● Replace liquid tank.
● Check lubricant for contami-
nation.
● Temperature of expansion
valve inlet is extremely low
as compared with areas
near liquid tank.
● Expansion valve inlet may
be frosted.
● Temperature difference
occurs somewhere in high-
pressure side
High-pressure pipe located
between receiver drier and
expansion valve is clogged.
● Check and repair malfunc-
tioning parts.
● Check lubricant for contami-
nation.
● Expansion valve and liquid
tank are warm or only cool
when touched.
Low refrigerant charge
↓
Leaking fittings or compo-
nents
Check refrigerant for leaks.
Refer to MTC-86, "
Checking
Refrigerant Leaks" .
There is a big temperature dif-
ference between expansion
valve inlet and outlet while the
valve itself is frosted.
Expansion valve closes a lit-
tle compared with the specifi-
cation.
↓
1. Improper expansion valve
adjustment
2. Malfunctioning thermal
valve
3. Outlet and inlet may be
clogged.
● Remove foreign particles by
using compressed air.
● Check lubricant for contami-
nation.
An area of the low-pressure
pipe is colder than areas near
the evaporator outlet.
Low-pressure pipe is clogged
or crushed.
● Check and repair malfunc-
tioning parts.
● Check lubricant for contami-
nation.
Air flow volume is not enough
or is too low.
Evaporator is frozen. ● Check intake sensor opera-
tion. Refer to MTC-66,
"INTAKE SENSOR" .
● Replace expansion valve.
AC353A