Toshiba MMU-P0121H Service Manual page 52

Check Detected Check
code position code name
A6 Interface Discharge
temp. TD1
alarm
A7 Interface TS
condition
gas leak
detection
AA Interface Pd sensor
alarm
Ab Interface Mis-
connection
of pressure
sensor
AE Interface Detection of
TD1
condition
gas leak
AF Interface Phase
order alarm
b4 Interface Ps sensor
alarm
Cause Trouble detection
(Position) condition
Discharge Protective stop was
temp. (TD1) repeated for more than
protective three times when discharge
operation temp. TD1 exceeded 130°C.
Suction temp. Protective stop when status
protective suction temp. TS is above
operation the criteria temp. continues
(TS1) for 10 minutes and repeats
for three times or more.
<TS alarm criteria temp.>
In cooling : 60°C or more
In heating : 40°C or more
High- Pd sensor output voltage is
pressure Pd zero (Sensor open).
sensor
Miswiring of • High-pressure Pd sensor
pressure and Low-pressure Ps
sensor sensor were exchanged.
(Pd, Ps)
• Output voltage of both
sensors are zero.
Discharge Protective stop when
temp. up discharge temp. TD1
when small detected 110°C or more
capacity of under condition that
indoor inverter compressor
operates. operated with low
(TD1) frequency and repeats for
three times.
Miswiring of Phase order error or
phase order missing one phase was
or missing detected when power was
one phase of turned on.
outdoor
Low-pressure • Ps sensor output voltage
Ps sensor was zero.
• Ps pressure detected
continuously 0.95MPa or
less during operation.
• Check outdoor service valve
(Gas side, liquid sides) fully open.
• Check for blockage of outdoor PMV.
1) Refrigerant choke circuit (PMV A)
2) Cooling bypass circuit (PMV B)
3) Liquid line check valve
(Cooling only model)
• Check characteristics of TD1 sensor
resistance value.
• Check 4-way valve error.
• Check refrigerant shortage.
• Check outdoor service valve (gas side, liquid
sides) fully open.
• Check for blockage of outdoor PMV.
1) Refrigerant choke circuit (PMV A)
2) Cooling bypass circuit (PMV B)
3) Liquid line check valve
(Cooling only model)
• Check characteristics of TS1 resistance value.
• Check 4-way valve error.
• Check connection of Pd sensor connector.
• Check Pd sensor error.
• Check outdoor P.C. board (Interface) error.
• Check connection of high-pressure Pd sensor
connector.
• Check connection of low-pressure Ps sensor
connector.
• Check pressure sensor Pd and Ps error.
• Check outdoor P.C. board (Interface) error.
• Check miswiring of fixed-speed compressor
terminal. (Inverse operation of fixed-speed
scroll compressor)
• Check compressor compressing error.
• Check refrigerant shortage.
• Check 4-way valve error.
• Check for blockage of outdoor PMV.
1) Refrigerant choke circuit (PMV A)
2) Cooling bypass circuit (PMV B)
3) Liquid line check valve
(Cooling only model)
• Check characteristics of TD1 sensor
resistance value.
• Check for blockage of indoor filter.
• Check for blockage of pipe.
• Check phase order missing phase of outdoor
power supply wiring.
• Check outdoor P.C. board (Interface) error.
• Misconnection of connector between Pd
sensor and Ps sensor.
• Check connection of Ps sensor.
• Check Ps sensor error.
• Check compressor error.
• Check 4-way valve error.
• Check outdoor P.C. board (Interface) error.
3-49
Check item (Position)