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Building Technologies
Boiler Sequence Controller RMK770
CE1P3132en
HVAC Products
6 Boiler sequence management
01.03.2005
If required, a boiler can be locked depending on the outside temperature.
Main menu > Commissioning > Settings > …
or
Main menu > Settings >
Boiler … > Operation settings
Operating line
Range
Factory setting
Outside temp lock limit value
---- / 5…30 °C
---- °C
If the composite outside temperature (refer to subsection 10.6.1 “The composite and
the attenuated outside temperature”) exceeds the limit value, the relevant boiler will be
locked, or only released again with low priority (see below under “Priorities“).
The boiler sequence manager keeps faulty boilers released. As long as the fault is
pending, function block “Boiler“ keeps the boiler switched off. When the fault is rectified,
the boiler will be put back into operation. The boiler sequence manager then decides if
and which boiler will have to be switched off.
As a result of the evaluation of the different settings and functions, the boilers are as-
signed different priorities for the switch-on sequence.
•
Priority 1 is always assigned to the fixed lead boiler (with no restriction)
•
Priority 2 is assigned to all the other boilers (with no restriction)
•
Priority 3 is assigned to the backup boilers
•
Priority 4 is assigned to the boilers with locking by the outside temperature
•
Priority 5 is assigned to the boilers with (conditional) manual locking (release input)
•
Priority 6 is assigned to the boilers with (unconditional) manual locking (release in-
put)
The boiler released first is always the boiler with the highest priority. If several boilers
have the same priority, they are released according to their order of changeover.
Then, the procedure is repeated with the next higher priority.
or
Main menu > Boiler sequence manager > Boiler sequence order
Operating line
Adjustable values / remarks
Address number lead boiler
1
Address number 1st lag boiler
2
Address number 2nd lag boiler
3
The “Boiler order“ menu shows the boiler order currently used.
6.3.3
Boiler sequence order
Normally, as the demand for heat increases, another boiler is switched on, whereby
only the first burner stage (x.1) is released first, followed by the second stage (x.2) or
modulation. Also refer to subsection 6.3.6 “Switching boilers on and off”.
Output stage
1 2
3
4
5
Boiler release
1.1 1.1+1.2 1.1+1.2+2.1 1.1+1.2+2.1+2.2 1.1+1.2+2.1+2.2+3.1
Boiler sequence with 4 boilers and 2-stage burners as an example. Lag boilers with
great setpoint increase.
Locking of boiler
depending on the
outside temperature
Boiler fault
Priorities
Diagnostic choice
boiler order
Standard
Example