6
x
Operation
91
FA ROTEX HeatPumpSolarUnit - Part 2 - 05/2009
[6] - Hysteresis (DT) for water heating
The parameter settings [6-XX] determine the temperature limits at which heating the hot water is started and stopped by the
heat pump (ON temperature and OFF temperature of the heat pump).
If the water temperature falls below the ON temperature of the heat pump (T
HP ON
), heating the hot water with the heat pump
is started.
As soon as the hot water temperature reaches the OFF temperature of the heat pump (T
HP OFF
) or the user target temperature
(TU), heating the water with the heat pump is stopped (the switch unit switches to room heating or the heat pump stops heating).
The following setting options are available:
– [6-00] Start: Temperature difference that determines the ON temperature of the heat pump (T
HP ON
).
– [6-01] Stop: Temperature difference that determines the OFF temperature of the heat pump (T
HP OFF
).
[7] - Step length for hot water
When the water is heated and the target temperature of the hot water (as set by the user) has been reached, the Booster Heater
(EHS) continues to heat the water to a temperature several degrees above the target temperature (OFF temperature Booster
Heater T
EHS OFF
). These additional degrees are defined in the parameter setting of the step length for hot water. The correct
setting prevents the Booster Heater (EHS) from repeatedly switching on and off (fluttering) while maintaining the target temper-
ature of the hot water.
The Booster Heater (EHS) switches on again when the hot water temperature falls 2 °C (fixed value) below the OFF temperature
for the Booster Heater (T
EHS OFF
).
The following setting options are available:
– [7-00] Step length for hot water: Temperature difference above the target temperature of the hot water before the Booster
Heater (EHS) is switched off.
T
Water temperature
T
HP MAX
Maximum water temperature of the heat pump
at the temperature sensor in the hot water
storage tank (55°C)
T
HP OFF
OFF temperature of the heat pump
T
HP ON
ON temperature of the heat pump
T
U
Target temperature for hot water (as set on
user interface on Page 78)
Fig.6-14
View of the control system for water heating with the heat pump
When the integrated temperature control in the Booster Heater (EHS) switches the Booster Heater (EHS) off, con-
trol by the ROTEX HeatPumpSolarUnit only works if this temperature control system has switched the Booster
Heater (EHS) on again.
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