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Building Technologies Boiler sequence controller RMK770 CE1P3132en
HVAC Products 6 Boiler sequence management 23.04.2009
On the basis of the plant’s layout, the number of boilers required for heat generation in
the summer are usually known (e.g. for DHW heating). If the “Summer operation“ state
is active in the boiler sequence manager, the number of boilers released can be limited.
Main menu > Commissioning > Settings > … or
Main menu > Settings > Boiler sequence manager > Summer operation
Operating line Range Factory setting
Number of boilers released 0…6 6
6.3.5 Sustained mode
When there is no demand for heat, there is no need for the boiler sequence to provide
heat. In that case, depending on the types of boiler used in the boiler sequence, all
boilers can be switched off or are maintained at a minimum temperature level. With
certain types of plant, it is important however to have heat available as quickly as
possible. For that purpose, a sustained mode can be defined. If there is no heat re-
quest, the temperature of the lead boiler is maintained at the adjusted sustained mode
setpoint. In that case, only the first stage of the lead boiler is released.
The minimum temperature of the relevant boiler is maintained depending on the pa-
rameter setting made, independent of the sustained mode setpoint.
Also, it can be selected whether or not a main pump – if installed – shall run during
sustained mode. If released in sustained mode, the main pump practically always runs.
Main menu > Commissioning > Settings > … or
Main menu > Settings > Boiler sequence manager > Sustained mode
Operating line Range Factory setting
Release main pump Yes / No No
Sustained mode setpoint ---- / 8…140 °C ---- °C
The binary control input for the boiler sequence release can interrupt sustained mode.
6.3.6 Switching boilers on and off
Based on the demand for heat and the current main flow temperature, the boiler se-
quence manager releases 1 or several boilers.
Main menu > Commissioning > Settings > … or
Main menu > Settings > Boiler sequence manager > Control parameters
Operating line Range Factory setting
Upward sequence integral 0…500 K×min 200 K×min
Downward sequence integral 0…500 K×min 50 K×min
Upward sequence delay 0…255 min 5 min
Shortened upward seq DHW
0…100%
0%
Additional boilers are released only if, for a certain period of time, the main flow tem-
perature stays below the neutral zone about the setpoint. The criterion used for switch-
ing on the second burner stage is a temperature-time integral.
TFlw
TFlx
TiDly
t
3132D04
Summer operation
Switching boilers on
Switching on via the
temperature-time integral
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