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Building Technologies
Modular Heating Controller RMH760B
CE1P3133en
HVAC Products
10 DHW heating
05.02.2007
In addition, the maintained secondary circuit serves as an additional discharge protec-
tion. But the “Discharge protection“ function remains active because the secondary
pump is controlled based on the primary temperatures on the heating side.
The maintained secondary circuit can only be used in connection with DHW plant types
DHW 3 through DHW 5.
The maintained secondary circuit is activated via configuration of the mixing valve.
Main menu > Commissioning > Extra configuration > DHW > Outputs > Maintained sec temp 3-
pos
> …
or
Main menu > Commissioning > Extra configuration > DHW > Outputs > Maintained sec temp
modulating
Assign terminal
For adapting the control parameters to the type of plant (actuator and controlled sys-
tem), the setting parameters to be used are the same as those used for mixing valve
control. They apply to both 3-position and DC 0…10 V actuators.
Main menu > Commissioning > Settings > …
or
Main menu > Settings > DHW > Controller maint sec temp
Operating line
Range
Factory setting
Actuator running time
1…600 s
150 s
P-band Xp
1…100 K
50 K
Integral action time Tn
0…600 s
60 s
Maintained sec circuit delta
–20…20 K
0 K
The maintained secondary circuit controls to the following setpoint:
Setpoint maintained secondary circuit = DHW setpoint
+
maintained secondary circuit delta
On completion of storage tank charging, the secondary pump will be deactivated and
the mixing valve will fully close. If the secondary sensor is faulty, the mixing valve for
the maintained secondary circuit will be opened.
10.5 Direct DHW heating
31
33
S
60
DHW 6
DHW heating takes place directly via the heat exchanger. Since there is no storage
tank so that charging control cannot be provided, control is permanently enabled.
The setpoint to be delivered by the heat source is made up of the current DHW setpoint
plus the setpoint increase of the heat exchanger.
For specific adaptation of the control parameters to the type of plant (actuator and
controlled system), additional setting parameters are available for direct DHW heating.
They apply to both 3-position and DC 0…10 V actuators.
Main menu > Commissioning > Settings > …
or
Main menu > Settings > DHW > Controller primary circuit
Operating line
Range
Factory setting
Heat exchanger setp increase
0…50 K
10 K
Actuator running time opening
1…600 s
15 s
Extra configuration
Settings
Maintained secondary
circuit delta
Mixing valve function
Settings