HDG Pelletmaster 15, Operation Manual

Page: 23 / 172

3 Mode of operation – Functional description
23
S
OLAR HEATING OF HOT
WATER
/
BUFFER
If the
Hot water tank lower sensor
temperature exceeds
the maximum, or if the temperature of the solar collector is not
sufficient to heat the hot water, the solar buffer pump will switch on
(speed controlled). The buffer tank will now be heated and the sun's
energy can be used for heating. If the maximum temperature of the
hot water tank has not yet been reached, the solar buffer pump will
switch off to establish whether the energy from the sun would be
sufficient to heat up the hot water tank. If this proves to be the case,
the solar pump will switch on again. If not, the solar buffer pump will
switch on again for the preset period.
P
ROTECTING THE COLLECTOR
FROM OVERHEATING
This is only active when solar heating is being used for the hot water
tank or for the combination buffer tank.
If the “protection temperature” for the collector is exceeded, the
solar pump will start, even if the maximum temperature for solar
heating has been exceeded. This protects the collector from
overheating.
S
PEED
-
CONTROLLED SOLAR
AND SOLAR BUFFER PUMPS
The speed of the solar pump is calculated from the temperature
difference between the collector and the tank, multiplied by the solar
pump factor. When the solar pumps start, they run for a configurable
time at maximum speed, before then being adjusted to between the
minimum and maximum pump speed.
D
ISTRICT HEATING CONNECTION
Operating with district heating is very similar to heating hot water. A
measurement of the temperature difference between the heat
source and the district heating transfer station is used to activate the
district heating pump. If operated without a buffer, the boiler supply
temperature is used as a reference. If operated with a buffer, the
temperature at the
Upper buffer tank sensor
is used. District
heating operation must be enabled via a parameter.
The district heating pump must be enabled via the
District
heating available
parameter, or, depending on the hydraulic
system set, may already be active.
The district heating pump is started when the temperature in the
transfer station falls below the
Transfer station preset
temperature
by the amount of the district heating hysteresis.
Priority for district heating can be set via the parameter “priority for
district heating”. For the other mixing circuits, this means that the
supply temperature can be lowered to the “reduced temperature for
district heating priority”.
C
ONTROL OF SECOND BOILER
The oil-fired boiler is activated when the temperature falls below the
maximum enable temperature (for the heating circuits or hot water
tank) for longer than the oil-fired boiler enable time.
If the temperature falls below the enable temperature for heating
hot water, the oil-fired boiler will start. In this mode of operation, the
preset oil-fired boiler temperature is the
Max. oil-fired