12. Optional functions
TCGB0075 rev.0 - 11/2012
148
12.1 Indoor unit
12.1.1 Optional functions
Optional function
Explanation
From LCD user
’s interface
Floor screed drying function (only circuit 2)
The screed function is used exclusively for the process of drying of newly
applied screed on floor heating system.
When user activates screed function, the water set point follows a predetermi-
ned schedule.
Automatic summer switch-OFF
The system will switch OFF the heating mode when the daily average outdoor
temperature of previous day rises above certain value at the summer switch-
OFF activation temperature, avoiding to provide heating at high outdoor tempe-
ratures.
Pump and motorized valve seizure protection
This function prevents the components of being sticked during long periods of
inactivity by running every week the components during a short period.
DHW anti-Legionella protection
In order to help protect against Legionella into the DHW system, it is available
an specific setting which will raise up the DHW set point periodically (by the
DHW tank electric heater or by a boiler) over the normal DHW tank temperature
setting.
Electrical tariff input
This function allows an external tariff switch device to switch OFF the heat
pump during peak electricity demand period. When the system is working in
combination with Boiler, the boiler will be switched ON to provide the necessary
heating.
Hydraulic separator combination
When the indoor unit’s water pump is not sized for heating installation (small
water pump) or when the system is configured to alternate when a boiler, an
hydraulic separator or buffer tank must be used to ensure proper hydraulic
balancing.
In this case, the hydraulic separator option can be enabled by the LCD user’s
interface.
From dip-switch setting
Anti freeze control (winter operation)
When YUTAKI S80 is operating in winter, if the outlet water temperature is 5ºC or
lower, and the unit remains in Thermo OFF Operation (and water pump OFF), the
water pump operates to protect the unit and pipes installation from freezing. This
control is released when the water outlet temperature becomes 7ºC or higher. It
function needs a dip-switch setting.
Electrical heater or boiler emergency mode
In the event of outdoor unit failure, the required heating can be provided by the
electric heater or by the boiler, by means of a dip-switch setting.
One step heater for three phase imbalance
option
In order to prevent 3-phase imbalance by the electric heater steps, this option
can be used to switch all 3 steps at the same time, by means of a dip-switch
setting.
N O T E
This function only applies when power source of the indoor unit
is 3-phase (3N~ 400V 50Hz).
2nd. outdoor temperature sensor accessory
In situations where the heat pump is located into a location where is not suitable
a temperature measurement to the system, it is available the 2nd. outdoor am-
bient temperature sensor.
YUTAKI S80 can use the two outdoor temperature sensors (Outdoor unit am-
bient temperature and Auxiliary ambient temperature) for the two space heating
circuits. It is necessary a dip-switch setting to use this temperature value ins-
tead of the outdoor ambient temperature value.
From 7-segment
Available four external outputs signals
There are available four output optional signals that provide four optional
functions of the system, programmed on the indoor unit PCB.
N O T E
In order to make easy the electrical connection works, HITACHI
offers as accessory a relay board for the additional output signals
(Auxiliary output signal box ATW-AOS-01).
N O T E
For the detailed information about optional functions, please refer to the Service Manual.