104/232
Building Technologies
Boiler Sequence Controller RMK770
CE1P3132en
HVAC Products
7 Boiler control
23.04.2009
7.2.2 Boiler
hydraulics
The following pumps are usually present:
•
One boiler pump per boiler
•
The main pump for all boilers
It is also possible to use a boiler pump as a mixing pump or a combination of mixing
pump and main pump.
A
B
T
31
3
2S
6
2
T
31
3
2
S
6
3
T
313
2S
64
T
T
31
3
2S
6
5
T
Boiler pump
Boiler mixing
pump
Main pump
Boiler mixing pump and
main pump
•
Plant types K1.x and K2.x use 1 main pump
•
Plant type K3.x uses 1 main pump and 1 mixing pump
•
Plant types K4.x, K5.x and K6.x use 1 boiler pump
By assigning an output to boiler pump A, a boiler pump is activated for the boiler. In
terms of configuration, no difference is made between boiler pump and mixing pump.
The function of this pump can be selected: Boiler pump or mixing pump.
Optionally, a twin pump can be used in place of the boiler pump. In that case, in addi-
tion to boiler pump A, boiler pump B in the extra configuration must be assigned an
output.
The single pump or twin pump can be monitored with a fault input and/or a flow switch.
For more detailed information, refer to section 5.8 “Pump control”.
If, in addition, a main pump shall be configured, this must be done on the “Boiler se-
quence manager” block.
Boiler pump B for boiler twin pumps.
T
313
2S
66
T
T
313
2S
67
T
313
2
S
68
T
In most cases, every boiler can be hydraulically decoupled by using a shutoff valve.
In the case of plant with a mixing valve for minimum limitation of the return temperature,
this function is performed by the mixing valve. If the boiler is not released, the mixing
valve is driven to the fully closed position so that the boiler is hydraulically decoupled
from the plant.
Shutoff valve for hydraulically decoupling the boiler from the system.
With the plant types using shutoff valves, the shutoff valves are configured to terminals
with changeover contact so that both an open and a close contact are available.
Often, the shutoff valve is controlled “parallel“ to the boiler pump (common output), or
the boiler pump is controlled parallel to the shutoff valve, but activated only when the
shutoff valve is fully open.
Definition of pumps
Boiler pump B
Shutoff valve
Shutoff valve