Siemens RDB160BN - 4-Pipe Fan Coil Unit Control; On;Off and Modulating Sequences

Applications
Control sequences
4
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WARNING
An electric heater must always be protected by a safety limit thermostat!
4.3.4 4-pipe fan coil unit
Heating and cooling
In 4-pipe applications, the thermostat controls two valves in heating and
cooling mode. 4-pipe application is the default setting for parameter P01 (P01
= 03).
The diagrams below show the control sequence for 2-position control.
On/Off control
Heating and cooling mode
T[°C
]
Room temperature
W
Room temperature setpoint
V1
Control command 'Valve' (H)
V2
Control command 'Valve' (C)
ΔT
Hysteresis (P10)
X
d
Dead zone (dead band) (P08)
Modulating control
PWM, DC 0…10 V or 3-position
Heating and cooling mode
T[°C
]
Room temperature
W
Room temperature setpoint
V1
Control command 'Valve' (H)
V2
Control command 'Valve' (C)
ΔT
Hysteresis (P10)
X
d
Dead zone (dead band) (P08)
NOTICE
The diagrams only show the PI proportional part of the thermostat.
For detailed information about setting the sequence and the control outputs
refer to chapters 'Applications [➙ 11]', 'Setpoint and sequences [➙ 18]' and
'Control outputs [➙ 20]'.
T
V1
1
0
Y
w
T [°C]
T
V2
X
DZ
V1
100
0
Y [%]
w
T [°C]
V2
X
DZ
X
P
X
P