Dhw Tank Functions - Fujitsu WATERSTAGE 112 Maintenance Document

Heat Pump, Split System, Single Service, 3 phase

6.3.9 DHW Tank Functions

DHW charging at the nominal setpoint temperature
(1610) always takes place in two stages. In the first
stage, only the heating pump heats the DHW tank.
The power supplied during this time is at its peak.
Then, when the heat pump is no longer able to supply
Charging Control
Line no. Programming line
5020 Flow setpoint boost
5024 Switching differential
5030 Charging time limitation
Flow setpoint boost :
The DHW demand made to the generator is
comprised of the current DHW setpoint plus the
adjustable setpoint boost.
Switching differential :
If the DHW temperature is lower than the current
setpoint minus the differential set here, the DHW
charging process is launched.
It ends when the temperature reaches the current
setpoint.
Information:
Forced charging is triggered on the first DHW
release of the day.
Charging is also launched when the DHW
temperature is within the differential, and as long as
it is not less than 1K above the setpoint.
Charging time limitation
During charging, the room heating (depending on
the charging priority defined on line 1630 and on
the hydraulic circuit) may be stopped or insufficient.
Therefore it is often advisable to limit the charging
process timewise to enable heating.
Maintenance Document 1394-1
enough heat to reach the setpoint value, it switches
on the DHW tank auxiliary if authorised. The auxiliary
will be cut off when charging is complete.
While the DHW tank charging process via the electric
auxiliary is finishing, the heat pump resumes heating.
If "- - -" has been selected the charging time
limitation will be deactivated. The DHW will be
heated to the nominal setpoint, even if the room
heating has not received enough power in the
meantime.
If a value between 10 and 600 is selected, charging
will be suspended after the time period set in
minutes, and will remain suspended over that time
before resuming. The generator power remains
available in the meantime to heat the room. This
cycle is repeated until the DHW nominal setpoint
has been reached.
Information:
When the room heating is stopped (summer mode,
economy function, etc.), DHW charging remains
active, regardless of the setting.
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