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Building Technologies
Boiler Sequence Controller RMK770
CE1P3132en
HVAC Products
9 Precontrol
01.03.2005
By configuring the outputs, it is defined whether a primary controller type 1 or type 2 is
used. Without configuration of a mixing valve, type 2 is automatically used. It is also
possible to define a flow temperature boost with the type 2 controller to compensate for
temperature losses in the case of long pipes.
9.2.2
Control of mixing valve
For control of the mixing valve, a 3-position or DC 0…10 V actuator can be used. The
selection is made by configuring the relevant output.
9.2.3
Pump control
The pump used with the primary controller offers the same choices as all the other
pumps. The pump can be monitored as an individual pump or, optionally, a twin pump
can be used as a pump of the primary controller. In that case, the relevant output must
be configured.
For more detailed information about pump control and twin pumps, refer to section 5.8
“Pump control and twin pumps”.
9.2.4
Return temperature limitation primary controller
r
If minimum or maximum limitation of the return temperature is required, a return tem-
perature sensor must also be configured.
Limitation of the return temperature is only possible with primary controller type 1. The
mixing valve of the primary controller can be used for maximum or minimum limitation
of the return temperature, depending on the type of hydraulic system.
31
31
S
57
Y1
B1
M1
B7
31
31
S
58
Y1
B1
M1
B7
Maximum limitation
Minimal limitation
Main menu > Commissioning > Extra configuration > Primary controller > Functions
Operating line
Range
Factory setting
Type of return temp limitation
Minimum / Maximum
Minimum
Main menu > Settings > Primary controller > Limitations
Operating line
Range
Factory setting
Return temperature min*
--- (none) / 0…140 °C
--- °C
Return temperature max*
--- (none) / 0…140 °C
--- °C
* Displayed or hidden, depending on the type of limitation
The function becomes active only if a valid value is set here.
If the return temperature exceeds the limit value, the primary controller’s flow tempera-
ture setpoint will be lowered. When the return temperature returns to a level below the
limit value, the lowering of the flow temperature setpoint will be gradually reduced.
Limitation operates as an I-controller whose integral action time can be adjusted.
Return sensor
Functions
Settings
Maximum limitation of
the return temperature