4
x
Parameter settings
39
FA ROTEX HPSU compact 308 - 02/2012
[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
).
>
<
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
main control unit (HPR1))
Fig. 4-5
View of the control system for water heating with the heat pump
[7] - Step length for hot water
If the hot water is heated and the set value temperature of the hot water (as set by the user) is reached, if the backup heater
(BUH) is installed and a booster request is received, the backup heater heats the hot water further to a temperature that is a few
degrees above the set temperature (OFF temperature of the booster request T
BOH OFF
). These additional degrees are defined in
the parameter setting of the step length for hot water. A correct setting for this value prevents repeated on and off cycles of the
backup heater (BUH) while retaining the set temperature of the hot water.
The backup heater (BUH) turns back on due to a booster request if the hot water temperature falls 2 °C (fixed value) below the
OFF temperature of the booster request (T
BOH OFF
).
If the temperature controller integrated into the backup heater (BUH) turns the backup heater (BUH) off, control
is carried out by the HPSU compact only if that temperature control turns the backup heater (BUH) back on.
The following setting options are available:
– [7-00] Step length for hot water: Temperature difference from the set temperature of the hot water, before the backup heater
(BUH) is turned off due to a no longer present booster request.
