Toshiba HWT-602S21SM3W-E(TR) Service Manual page 115

Diagnostic functional operation
Check
code
Operational cause
Overheat protection operation
When the thermostat of the backup
heater activates during the operation of
A09
the heat pump or backup heater.
When the thermostat operation is
activated while it has been stopped.
Antifreeze operation (2)
When TC + TWO < -15K detected in
A10
cooling mode.
Operation of the release protection
When the TWO release counts to 10.
A11
Heating, hot water heater failure
The antifreeze control is detected under
the condition of TWI < 15°C while TWI ≥
A12
15°C, TTW ≥ 20°C is not detected after
the heater backup.
Pump failure
A13
Pump failure
A14
Determination and action
Backup Automatic
operation reset
1. No water (heating without water) or
no water flow.
2. Failure of the flow sensor.
X X
3. Failure of the backup heater (poor
automatic reset thermostat).
1. Almost few water flow.
O X
2. Failure of the flow sensor.
3. Low refrigerant.
Heating
1. Almost no water flow.
X
2. Failure of the flow sensor.
X
Hot water
3. Check the water outlet temperature
O
4. sensor (TWO).
1. Activated by a large load of heating
or hot water supply.
2. Check the heater power circuit
O O
(backup or hot water cylinder
heater).
• Power supply voltage, breaker,
power supply connection
1. Pump has stopped by a certain
cause.
• Low supply voltage.
• High humidity around the electric
box of the pump.
• Dew condensation to the electric
X X
board of the pump.
• Pump lock due to clogging or dust.
• Once turn off the power supply to
the system and turn on again and
operate the system.
Mainly low voltage to the system.
1. Pump has stopped by a certain
cause.
• Low supply voltage.
• High humidity around the electric
box of the pump.
• Dew condensation to the electric
board of the pump.
X X
• Pump lock due to clogging or dust.
• Once turn off the power supply to
the system and turn on again and
operate the system.
Mainly except low voltage to the
system.
114
Number of
abnormalities Detailed
for item
confirmation
2
112
1
10 113
10 114
1 115
2 116
2 116