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Troubleshooting by Indication on the Remote Controller
SiUS30-1301
246
Service Diagnosis
Check for Overcharge of Refrigerant.
In case of VRV Systems, the only way to judge as the overcharge of refrigerant is with operating
conditions due to the relationship to pressure control and electronic expansion valve control.
As information for making a judgement, refer to information provided below.
Diagnosis of overcharge of refrigerant
1. High pressure rises. Consequently, overload control is exercised to cause scant cooling
capacity.
2. The superheated degree of suction gas lowers (or the wet operation is performed).
Consequently, the compressor becomes lower in discharge pipe temperature despite of
pressure loads.
3. The subcooling degree of condensing rises. Consequently, in heating, the temperature of outlet
air passing through the subcooling section becomes lower.
CHECK 6
Cooling
High press
u
re
Lo
w
press
u
re
Fre
qu
ency
High press
u
re
grad
u
ally rises
w
ith
increase in fre
qu
ency.
S
ub
cooling degree
b
ecomes higher.
(Li
qu
id connection
pipe temperat
u
re
lo
w
ers.)
Lo
w
press
u
re rises
d
u
e to red
u
ced
compressor o
u
tp
u
t.
High press
u
re
Lo
w
press
u
re
Fre
qu
ency
Heating
The condensing
u
nit electronic
expansion
v
al
v
e is closed d
u
e to
the o
v
erload control.
Fre
qu
ency comes to
the minim
u
m le
v
el.
(High press
u
re is maintained
at a constant le
v
el.)
Lo
w
press
u
re rises
d
u
e to red
u
ced
fre
qu
ency.
To maintain high press
u
re,
fre
qu
ency red
u
ces
u
nder the
capacity control.
High press
u
re drops or rises
immediately after the o
v
erload
control is complete.
Lo
w
press
u
re drops d
u
e to
closed condensing
u
nit
electronic expansion
v
al
v
e.
Hot gas
b
ypass is acti
v
ated
for lo
w
press
u
re protection,
i.e., h
u
nting at lo
w
press
u
re.
Higher degree of o
v
ercharge
(Degree of o
v
ercharge)
Proper
qu
antity
Fre
qu
ency comes to
the minim
u
m le
v
el.
High press
u
re
drooping control
(Lo
w
press
u
re is
maintained at a
constant le
v
el.)
To maintain lo
w
press
u
re,
fre
qu
ency increases
u
nder
the capacity control.