89
DHW control functions
SMGB0066 rev.0 - 12/2009
Controller pack
Service Manual
4
Situation 2:
P10 > dSET_HP
The Heat Pump is used to heat the DHW tank to the temperature DSET_HP. Then
the DHW electric heater is switched on to heat the DHW tank to the temperature
DSET. With slow reductions in DHW temperature, the DHW electric heater is
switched on again when the DHW temperature falls below DSET minus P11. With a
large reductions in DHW temperature (for example, a large draw-off from the tank,
or after a period of DHW blocking), when the DHW temperature falls below DSET_
HP minus P11, the heat pump is again used to heat the DHW tank to DSET_HP
before the DHW electric heater is switched on again.
Parameter Setting:
P10 DHW setpoint
P34 DHW Electric Heater Waiting Time (default 45 min)
EP39 DHW offset for maximum heat pump supply temperature (default 7K)
Engineering Parameters (EP) are only available for service engineers.
note
The electric heater should have its own thermostat set to a higher value than the
DHW setpoint of the System Controller. Please take care about the type of DHW
storage tank fitted and the position of the electric heater.
4.4.4.2. Using the Boiler for dHW loading
Configuration Specific
Applies only to configurations CONF 3,5
function
The boiler may also be used to raise the temperature of the DHW tank if the Heat
Pump is not able to reach the DHW supply setpoint by itself. The boiler will only
start after a time delay defined by parameter P19 (waiting time for boiler) in order to
allow the Heat Pump time to satisfy the DHW loading demand by itself.
Exception: If the installer parameter P10 (DSET) is higher than DSET_HP, this
means the boiler is always needed to heat the DHW tank. In this case the boiler
waiting time (P19) does not apply.
DSET_HP = the maximum temperature to which the heat pump can heat the DHW
tank
= Heat Pump maximum supply temperature (EP29 or EP33) – EP39
Parameter Setting
P10 DHW setpoint
P19 Waiting Time for Boiler (default 30 min)
EP39 DHW offset for maximum heat pump supply temperature (default 7K)
Engineering Parameters (EP) are only available for service engineers.