HDG Compact 25, Operation Manual, Page: 23 / 188

3 Mode of operation – Functional description
23
C
ONTROL MODES
You can choose between four control modes:
• Fixed value :
– constant feed rate and constant combustion air flow rate (also
in emergency operation)
• Combustion control :
– Constant, specified combustion chamber temperature and op-
timal combustion through modification of primary and secon-
dary air and fuel quantity
– No output regulation
– Preferred method of operation with buffer tank
• Control of combustion and power :
– Output supplied is adjusted to heat used with optimised com-
bustion
– Operation without accumulator
• Log wood
– only suitable for emergency operation
HDG H
YDRONIC
The HDG Hydronic is a heating system regulator which is attuned to
the HDG hydraulic systems.
The HDG Hydronic handles the overall energy management for the
heating system and, depending on the version, controls up to three
weather-controlled heating circuits as well as:
• Heating hot water
• Transfer of heat into the district heating grid
• Integration of second boiler
• Solar system for hot water and support of the heating system
HDG H
YDRONIC CONTROL FUNCTIONS
B
ASIC FUNCTIONS OF THE
HEATING CIRCUIT CONTROL
The heating circuit control always operates at a characteristic heating
curve controlled by the outside air temperature. For each heating
system, the characteristic heating curve is used to calculate the
supply water temperature which is appropriate for the current out-
side temperature. Other factors which influence the calculated water
temperature are the steepness of the characteristic heating curve,
the correction for this (parallel shift) and the preset value for the
room temperature.
If the heating circuit control is operating, room temperature will be
adjusted to a preset daytime or night-time value.