eta TWIN - Page 23

Configuration parameter [Buffer] function block – TWIN
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Explanation of [Flow temp raise]
This parameter applies only for the TWIN pellet
burner and not for the log boiler.
The buffer target temperature [Buffer target] is
increased by this value when the buffer demands heat
from the pellet burner.
Example:
[Buffer target] = 70 °C
[Flow temp raise] = 5 °C
=> The buffer demands 75 °C from the pellet burner.
The pellet burner target temperature is therefore 75
°C.
Explanation of [Enable temperature]
This parameter specifies the minimum boiler
temperature for charging the buffer when burning logs.
Buffer charging can only occur when the boiler has
exceeded this temperature.
Explanation of [... with TWIN]
This parameter specifies the minimum boiler
temperature for charging the buffer during pellet
operation. Buffer charging can only occur when the
boiler has exceeded this temperature.
Explanation of [Buffer bottom off]
This parameter ends charging of the buffer storage
tank by the boiler. As soon as the [Buffer bottom]
temperature sensor in the buffer storage tank has
exceeded the configured [Buffer bottom off] tempera-
ture, charging of the buffer by the boiler is stopped.
Normally, when the boiler is primarily burning
logs, this parameter does not need to be
changed. And the [Full buffer charge with pellets]
parameter remains at its factory setting of [No],
ensuring that the buffer cannot be fully charged during
pellet operation and is able to absorb sufficient heat
when the log boiler is started up in the meantime.
The [Full buffer charge with pellets] parameter
should be set to [Yes] only in exceptional cases
when the boiler is in pellet operation more than 80% of
the time. Then the buffer will be fully charged in pellet
operation and the [Buffer bottom off] can also be set
higher.
Then if the log boiler is to be started up, the TWIN
pellet burner must be manually switched off first. Only
when the buffer charging status is low enough can the
log boiler be started.
Explanation of [Enable difference]
The boiler temperature must be higher than the [Buffer
bottom] temperature by this value in order for the boiler
pump or buffer charging pump to switch on.
Explanation of [Effective buffer volume [l]]
The effective buffer volume is the buffer volume from
the highest point of the buffer to the height of the return
connection to the boiler.
If several buffers are connected in series, the
effective volume of each individual buffer is
added together and the total volume entered in the
control system.
Explanation of [Desired charging time]
This parameter specifies the time that the boiler is
allowed to take to charge the buffer to the required
target temperature [Buffer target].
Only change this parameter if the [Full buffer
charge with pellets] parameter has been set to
[Yes].
Explanation of [Return from consumers]
This temperature is the mean return temperature of all
consumers connected to the buffer. For example:
heating circuits, hot water tanks, external heat
consumers fresh, water modules...
This temperature forms the basis for calculating the
buffer charging status.
Explanation of [Full buffer charge with pellets]
This parameter is used to determine whether the buffer
may be completely charged by the TWIN pellet burner.
If the boiler is operated primarily with logs, the factory
setting [No] remains in effect. Then the load reduction
on startup in the buffer top activates and only this part
is charged. This ensures that the buffer can absorb
enough heat if the log boiler is started up.
With the [Yes] setting, the load reduction on startup is
also switched downwards and the buffer can be fully
charged. Only select this setting when the boiler is in
pellet operation for more than 80% of the time.
If [Yes] is set, the parameter [Buffer bottom off]
must also be adjusted.
Explanation of [Residual heat usage]
This setting specifies how far the boiler is allowed to
cool off after it has burned the wood.
Possible settings:
• [Diff. buffer bottom]: The buffer absorbs residual
heat until the boiler temperature is below [Buffer
bottom], but at most only until temperature [Enable
temperature] is reached.
• [Diff. buffer top]: The buffer absorbs residual heat
until the boiler temperature is below [Buffer top],
but at most only until temperature [Enable tem-
perature] is reached.