Controller pack
Service Manual
76
System configuration, settings and control system
SMGB0066 rev.0 - 12/2009
dHW Storage
•
The System Controller can be used in a system which has a DHW storage tank, with either a diverting valve or pump.
If the system has a separate DHW pump, then a hydraulic separator or buffer tank has to be used to ensure proper
hydraulic balancing of the system.
The DHW system type is selected by an installer parameter (P1)
Buffer Tank or Hydraulic Separator
•
When a hydraulic separator or buffer tank is used in CONF 1 & 2, the system will contain a secondary pump on the
distribution side of the separator/buffer. In this case it is necessary to set installer parameter P2 to 1.
In bi-valent systems (CONF 3,4,5) a hydraulic separator or buffer tank is always needed.
4.1.7. Principle of bi-valent or mono-energetic operation
function
•
Bi-valent and mono-energetic systems use an auxiliary heat source (boiler or electric heater respectively) in addition to
the heat pump.
At higher outdoor temperatures, the heat pump can provide all the heating requirements of the system, and it is not
necessary to switch on the auxiliary heat source. However at lower outdoor temperatures, the electric heater or boiler is
used to provide the increased heating demand. The changeover point for bi-valent or mono-energetic operation is called
the balance point. A +/-0.5K control differential is applied to the switching between the operating modes.
Outdoor temperature (TEXT) > Balance Point (BP)+0.5K, the boiler or electric heater is not used. (Exception is that the
boiler can be used for DHW loading.)
Outdoor temperature (TEXT) < Balance point (BP)-0.5K, the system controller determines whether to switch on the boiler
or electric heater depending on the heating requirements. Refer to the sections on Boiler Control and Electric Heater
Control for more details.
Installer Parameters
•
P15 Maximum Outdoor Temperature for Boiler/Electric Heater Operation = Balance Point (BP) (default 0°C)
P14 Minimum Outdoor Temperature for Heat Pump Operation (CONF 3,4,5 only) (default -20°C)
note
Parameter P15 can be set to OFF, in which case the boiler or electric heater is allowed to operate at all outdoor
-
temperatures
Parameter P14 can be set to OFF, in which case the heat pump is allowed to operate at all outdoor
-
temperatures.
Configuration Specific
•
CONF 2 Mono-Energetic Systems
-
The electric heater is used to “top-up” the energy required for the system. The System Controller tries to ensure that
the heat pump is always running when the electric heater is used, but there may be some circumstances where the
electric heater is providing all the energy for the heating system.
Heating Zone
Heat Pump Capacity (kW)
Heat Demand (kW)
Electric Heater
Heat Pump
Only
Heat Pump
20ºC
P15
-20ºC Outside Temp
Heat Pump operates
on it’s own down to the
balance point (installer
parameter
P15
)
Heat Pump plus
Electric Heater
operate together