57
Check
code
Diagnostic functional operation
Determination and action
Defect
frequency
confirmation
Operational cause
Backup
present
Automatic
reset
A09
Overheat protection operation
When the thermostat of the backup heater
activates during the operation of the heat pump
or backup heater. When the thermostat
operation is activated while it has been stopped.
O
×
1. No water (heating without
water) or no water flow.
2. Defect of the flow switch.
2
3. Defect of the backup heater
(poor automatic reset thermostat).
1
A10
Antifreeze operation (2)- cooling mode only
When TC + TWO < -15°C
x
×
1. Almost no water flow
2. Defect of the flow switch
3. Low refrigerant charge
10
A11
Operation of the release protection
When the TWO release counts to 10.
1. Almost no water flow.
2. Defect of the flow switch.
3. Check the water outlet
temperature sensor (TWO).
10
A12
Heating, hot water heater
The antifreeze control is detected under the
condition of TWI<20°C while TWI>15°C,
TTW>20°C is not detected after the heater
backup.
O
O
1. Activated by a large load of
heating or hot water supply.
2. Check the heater power circuit
(backup or hot water cylinder
heater). • Power supply voltage,
breaker, power supply connection
1
E03
Regular communication error between hydro
unit and remote controller
When there is no regular communication from
the remote control for 3 min, or when no remote
control is equipped.
×
O
1. Check remote control
connection. 2. Defect in the
remote control.
1
E04
Regular communication error between hydro
unit and outdoor unit
The serial signal cannot be received from
outdoor.
O
O
1. Check the serial
circuit. •
Miswiring of the crossover
between the water heat
exchanger and the outdoor unit
1
F03
TC sensor error
Open or short circuit in the heat exchange
temperature sensor.
O
O
1. Check the resistance value and
connection of the heat exchange
temperature sensor (TC).
1
F10
TWI sensor error
Open or short circuit in the water inlet
temperature sensor.
O
O
1. Check the resistance value and
connection of the water inlet
temperature sensor (TWI).
1
F11
TWO sensor error
Open or short circuit in the water outlet
temperature sensor.
×
O
1. Check the resistance value and
connection of the water outlet
temperature sensor (TWO).
1
F14
TTW sensor error
Open or short circuit in the hot water cylinder
sensor.
×
O
1. Check the resistance value and
connection of the hot water
cylinder sensor (TTW).
1
F17
TFI sensor error
Open or short circuit in the floor temperature
sensor.
×
O
1. Check the resistance value and
connection of the floor-inlet
temperature sensor (TFI).
1
F18
THO sensor error
Open or short circuit in the heater outlet
temperature sensor.
×
O
1. Check the resistance value and
connection of the heater outlet
temperature sensor (THO).
1
F19
Detection of THO disconnection error
When TWO
–THO>15K is detected and 30 sec
elapsed.
×
×
1. Check for any disconnection of
the heater outlet temperature
sensor (THO).
1
F20
TFI sensor error
When TWO
–TFI>30K is detected and
TFI<TWI
–5K is detected.
×
×
1. Check the connection of the
floor-inlet temperature sensor
(TFI).
1
