Herz pelletfire 20/20, Operating Instructions Manual

Page: 11 / 100

Boiler operation 5
11
Too short and thick wood logs
lead to
an uneven burning
behaviour. Too short and thin
wood reduces the burning time.
→
Only use wood logs according
to specification
It is imperative that all doors are
closed during operation so that no
leak
air can disrupt the
combustion process.
The heating-up time can change
due to the cleaning condition of
the boiler, the local conditions, the
used fuels and the weather
changes (low pressure in the
exhaust system).
The boiler operates according to the principle of
the lower burn-up. The control device controls the
boiler automatically and completely.
5.3 Cold system start up
After a long period of not being used, you should
take particular note of the following points when
starting up the system:
◼
Where the equipment has cooled down, the
boiler requires a proportionate amount of
time to reach temperature if all heat
consumers are switched on during the
heating up process. Therefore, firstly put only
one small heating circuit into operation and
switch the other heating circuits only on when
the boiler has reached its operating
temperature. The first start-up should only be
carried out by HERZ factory customer service
or persons authorised as such.
5.4 Boiler in combination mode
(automatic mode)
If the buffer or heating circuits require heat after
burning of all logs, the operation is automatically
continued with pellets.
In combination mode the boiler works as a
automatically fed system. After power up the
boiler is ready for operational.
The start of the combustion occurs automatically
after heat it requested or at a defined starting
point. When at this time the boiler is filled with log
wood, the ignition of the log wood starts with the
pellet burner. After burning off of the log wood and
if there is a heat request, the boiler starts
automatically in pellets mode.
5.5 Feeding system (pellet)
The fuel is fed from the fuel storage room by the
room discharge system to the burn back
protection device. Fuel passes the hopper first,
afterwards the back burn flap. The back burn flap
gets steered by a spring loaded servo motor. If the
servo motor operates current less, the back burn
flap will close independently. Next the fuel is fed
towards the burning chamber by the feeding
screw. These are then directed to the combustion
chamber via a drop level. The achieved fuel level
is a crucial factor of the boiler heat output and
operating mode.
5.6 Feeding type
The operation of the pelletfire is based on a pulse-
no-pulse ratio, which controls the feeding system.
All the values are to be set via the menu “Fuel
values” (only available in the service area). These
feed values are corrected by the combustion
control system.
5.7 Combustion air control
The supplied combustion air is differentiated
between primary and secondary air. The primary
air is initiated directly into the embers. The
secondary air gets used to actuate the developed
flame to a completely. The air supply is piped via
vents on the burner side (underneath side cover).
The flue gas ventilator is a suction fan and this is
located at the back of the boiler. It generates low
pressure in the boiler. The secondary- and
primary air get sucked out due low pressure.
The ID-fan is time-controlled by the variable-
speed electronic control. The ID-fan speed is
controlled according to the boiler temperature and
rectified by the lambda control.
5.8 Boiler operation
The boiler starts up automatically with its built-in
automatic ignition, when heat is required.
The heat requirement can be controlled by the
weather or by a remote sensor (optional),
depending on any heating circuit. A room
thermometer can also be used to generate a
requirement. The boiler can also be started up by
the requirement of a hot water tank.
The boiler output can be controlled by set up
values and adjusted to local conditions.
The boiler control prevents too low boiler
temperatures to avoid effect on the durability of
the system. Too high boiler temperatures are not
permissible.
Expansion cracks at insulating plates, respectively
burning chamber stones, don´t affect their
capacities and don´t represent warranty claim.