User Operation / Indication - Siemens RDG20 KN Series Basic Documentation

Return flow temperature
control (P061/P062)
Note
Setting
Note

4.6.5 User operation / Indication

Note
Button lock (P028)
A6V11545892_en--_e
For district heating systems (2-pipe systems), this function is used to increase the
system efficiency. It guarantees that the delta temperature between flow and return
temperature for water does not drop below the defined setpoint selected by P061
for cooling and P062 for heating.
As a result, the water flow and speed are reduced with a consequent reduction of
noise and energy consumption.
●
When the multifunctional input P150, P153 or P155 is set to 14 (Coil return
temperature), the parameters P061 (Setpoint ΔT cooling) and P062 (Setpoint
ΔT heating) are visible.
●
Set P061 or P062 or both to the requested value to activate the return flow
temperature control function
Applications with flow and return temperature sensors, the sensors are wired
directly to the thermostat:
Function
Sensor 1 Flow temperature
Flow temperature and changeover
Sensor 2 Return temperature
1)
(P15x = 12) If the flow temperature value is provided via KNX, the corresponding
multifunctional input setting (= 12) must be removed. (RDG2..KN)
2)
(P15x = 2) The sensor temperature value is used for the changeover function
and flow temperature. If the thermostat receives the flow temperature value from
the bus, the thermostat works according to the flow value provided via bus (bus
has higher priority). (RDG2..KN)
To receive the flow temperature via bus from a Synco device, set the same value
for distribution zone heating / colling (P903...P905) of the Synco device and
thermostats. (RDG2..KN)
For an accurate delta temperature control performance, we recommended using
the same cable type and length for both flow and return sensors.
When the thermostat is set as subordinate (P258 = 0), P005 (scheduler), P028
(keypad), P110 (energy indicator) and P111 (energy indicator range) are invisible
and the subordinate synchronizes the related operation with its manager.
(RDG2..KN)
If the "Button lock" function is enabled by P028, lock or unlock them by pressing
the right button for 3 seconds.
If "Auto lock" is configured, the thermostat automatically locks the buttons 10
seconds after the last adjustment.
P028 can be configured as following:
P028
0 Unlocked
1 Auto lock
2 Manual lock
3 Auto lock operating mode
4 Auto lock setpoint shift
5 Auto lock fan speed
1)
2)
locked
locked
locked
Functions
Additional functions
Multifunctional inputs P150, P153, P155
= 12 (Coil flow temperature)
= 2 (H/C changeover)
= 14 (Coil return temperature)
locked locked locked
locked locked locked
locked
locked
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