Hitachi YUTAKI RWM-2R1E Installation & Operation Manual page 175

UNIT CONTROLLER (PC-ARFH1E)
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Solar combination - Total control
ΔT connection:
• Allows to specify a difference temperature
between tank and Panel temperature to
allow solar operation. Solar operation is
allowed in case Panel temperature is "ΔT
connection" ºC above tank temperature.
ΔT disconnection:
• Allows to specify a difference temperature
between tank and Panel temperature to
stop solar operation. Solar operation is not
allowed in case Panel temperature is "ΔT
connection"ºC below tank temperature
Panel antifreeze temperature:
• Minimum Solar panel temperature at
which Solar Pump is switched ON in order
to protect system against frost formation at
pipes due to low ambient temperature.
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Boiler combination
Minimum ON time:
• Time that must pass before stop
boiler after being switched ON
Minimum OFF time:
• Time that must pass before start
boiler after being switched OFF
Wait time for DHW:
• Delay time to start Boiler for DHW
in case all conditions allow Boiler
to start after HP has been started
for DHW.
161 PMML0575 rev.2 - 03/2022
DHW maximum time:
• Maximum time YUTAKI allows to heat tank by
means Solar. At the end of this time Solar pump is
stopped regardless temperature conditions at Solar
Panel.
DHW minimum time:
• Minimum Time solar operation cannot be performed
once it has been stopped due to DHW Maximum
Time or due to low temperature at solar panel.
DHWT maximum storage temperature:
• Maximum DHW temperature that allows Solar
operation.
Panel minimum temperature:
• Minimum temperature of the solar Panel to allow
Solar operation
Panel overheat temperature:
• Maximum panel operation temperature at which
Solar Pump is set to off in case Panel sensor reads
a temperature above this value in order to protect
system.
• In case that the solar pump is stopped due to panel
overheat temperature, the YUTAKI unit sets solar
overheat output to high state provided that this
function has been setup as described in
Setup of inputs, outputs and sensors"
Bivalent point:
• Boiler is allowed to operate in case ambient temperature is
below this value
Combination mode:
• Serial: Boiler operates in series with the heat-pump. The
boiler provides additional peak load capacity and works
together with the HP
• Parallel: Boiler operates in parallel with the heat pump.
The boiler provides the full heating requirements. In case
Boiler is ON, HP is not allowed to operate
Supply setting offset:
• Setting offset for Boiler. Higher values imply earlier
stoppage of Boiler and vice versa.
Waiting time:
• Delay time to start Boiler in case all conditions allow Boiler
to start after HP has been started for Space Heating
DHW by boiler:
• Control to allow heat
DHW by means Boiler
"10.6.2.9