Hydro Unit
Alarm
Alarm description and generation/reset conditions
indication
Hot water cylinder temperature TTW sensor defect
F14
If short-circuit or open-circuit state continues for two seconds, an alarm occurs.
Auto-reset: When normal value is confirmed
Floor inlet temperature TFI sensor defect
F17
If short-circuit or open-circuit state continues for two seconds, an alarm occurs.
Auto-reset: When normal value is confirmed
Internal heater outlet temperature TWO sensor defect
F18
If short-circuit or open-circuit state continues for two seconds, an alarm occurs.
Auto-reset: When normal value is confirmed
Floor inlet temperature TFI sensor disconnection or wrong installation
F20
(This alarm is reset by stopping operation and is checked again.)
Low-pressure sensor defect
F23
If open-circuit state continues for two seconds, an alarm occurs.
Auto-reset: When normal value is confirmed
Hydraulic heat exchanger EEPROM defect
One mismatch is detected if there is no verification ACK after data write to the EEPROM
F29
Reset condition: This alarm is inhibited while the unit is not working.
(When EEPROM1K is mounted, this alarm cannot be reset.)
Onboard expansion IC defect
F30
This alarm is not reset automatically.
Group line in an hydro unit
This alarm is checked during initial communication immediately after power-on.
L07
This alarm occurs immediately after operation start.
This alarm is not reset automatically. (This alarm is inhibited while the unit is not working, but occurs again after
the unit operates.)
Hydro unit capacity has not been set.
This alarm is checked immediately after power-on.
L09
This alarm is not reset automatically. (This alarm is inhibited while the unit is not working, but occurs again after
the unit operates.)
Pump defect or abnormal flow rate
A01
This alarm is not reset automatically.
Excessive water temperature increase by the heating heater
A02
Auto-reset:
A03
Excessive water temperature increase in the hot water cylinder
Freezing is detected.
A04
Auto-reset:
High-pressure switch malfunction
A07
This alarm is not reset automatically.
Low-pressure sensor malfunction
A08
This alarm is not reset automatically.
Overheat preventive operation malfunction
A09
Auto-reset: When operation mode is changed
Release preventive operation malfunction
A11
This alarm occurs when the Hydro Unit enters the forced-stop zone 10 times.
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Installation Manual