Controller pack
Service Manual
90
DHW control functions
SMGB0066 rev.0 - 12/2009
4.4.5. 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.
Parameter Setting
•
P19 Waiting Time for Boiler (default 30 min)
4.4.6. response of the Heat pump to a dHW demand
function
•
Since the heat pump only reads the control signal (mA) once every 20 minutes there can be a delay before the system
responds to the DHW request. In order to improve this response time, the System Controller uses a feature of the heat
pump that when the control signal is set to its highest value, it responds immediately. So if the supply setpoint has to be
increased due to a DHW demand, then the supply setpoint is set to the parameter EP29 (Heat Pump maximum supply
temperature) for a certain time. This time is the Heat Pump Max Time High Setpoint (EP35). When this time period
expires, the Supply Setpoint is set to the normal calculated DHW supply setpoint.
Parameter Setting
•
EP35
Heat Pump Max Time High Setpoint (default 180sec)
note
Engineering Parameters (EP) are only available for service engineers
-
4.4.7. dHW Time Program
function
•
A DHW time program is not provided inside the controller. An external timer can be used by itself or together with a tariff-
switch device. For example, with an external timer it is possible to block DHW loading during daytime periods.
It is possible to use
only a external timer. Operates according to EP24 setting.
1.
an external timer in series with a tariff-switch device. In this case:
2.
if EP24=3 both the external timer and the tariff-switch contacts must be closed to allow DHW loading
if EP24=4 either of the external timer or the tariff-switch contacts can be open to allow DHW loading.
an external timer in parallel with a tariff-switch device. In this case:
3.
if EP24=3 either of the external timer or the tariff-switch contacts can be open to allow DHW loading
if EP24=4 both the external timer and the tariff-switch contacts must be closed to allow DHW loading.
only a tariff switch device. Operates according to EP24 setting.
4.
Depending on the setting of the configuration of tariff/timer input parameter (EP24), DHW loading can be blocked
according to the status of the input (open or closed).
