4-Pipe Fan Coil Unit With Electric Heater (Rdg100Kn) - Siemens RDG100KN Basic Documentation

Heating and cooling with
auxiliary heater
Electric heating in
heating mode
Digital input "Enable
electric heater
"
K N X
R
Enable electric heater
Caution
4-pipe application with
manual changeover
"Main and secondary"
application
On/Off control
Heating mode with manual selection (P01 = 2)
Y
YE
1
0
½ SDH ½ SDH
½ SDH
W
D
Heating and cooling mode (P01 = 4)
YE
Y
1
0
½ SDH ½ SDH
½ SDH
W
D
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Siemens
Building Technologies
3.6.7

4-pipe fan coil unit with electric heater (RDG100KN)

On 4-pipe applications with electric heater, the thermostat controls 2 valves in
heating and cooling mode by manual selection, heating and cooling mode with
automatic changeover, heating only, or cooling only plus an auxiliary electric
heater. Heating and cooling is factory-set (P01 = 4).
The electric heater is used as an additional heat source when the heating energy
controlled by the valve is insufficient.
The electric heater receives an ON command when the temperature is below
"setpoint" minus "1/2 "dead zone" minus "setpoint differential" (= setpoint for
electric heater).
Remote enabling/disabling of the electric heater is possible via input X1, X2, or D1
for tariff regulations, energy saving, etc.
Input X1, X2, or D1 must be commissioned accordingly (P38, P40 and P42). See
3.9.
The electric heater can also be enabled/disabled via bus.
Do not assign the function to a local input X1, X2 or D1 if the bus input is used.
An electric heater must always be protected by a safety limit thermostat!
The heating or cooling output can be released via operating mode button if P01 is
set to Manual (P01 = 2).
See 3.6.6.
The diagrams below show the control sequence for On/Off control.
YH
w
T[°C]
½ SDH
YH
YC
x x
½ ½
dz dz
w
½ SDC ½ SDC
½ SDH
RDG100KN, RDG160KN, RDG165KN Basic Documentation
Cooling mode with manual selection P01 = 2)
Y
1
0
T[°C] Room temperature
w Room temperature setpoint
YE Control command "El heater"
YH Control command "Valve" (heating)
T[°C]
YC Control command "Valve" (cooling)
SDH Switching differential "Heating" (P30)
SDC Switching differential "Cooling" (P31)
X Dead zone (P33)
dz
w Setpoint differential (P34)
D
YC
w
T[°C]
½ SDC ½ SDC
CE1P3191en
2018-07-03