Siemens RDG100 Documentation page 38

1-speed / 3-speed fan
Control sequence
for modulating fan
(ECM fan)
Note:
Manual operation
(ECM fan)
Fan operation as per
heating / cooling
mode, or disabled
Fan minimum
on- time
Fan operation in
dead zone (fan kick)
38 / 60
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The fan speed thermostat can control a 1-speed or 3-speed fan (selected via
control parameter P53). A 1-speed fan is connected to terminal Q1, a 3-speed fan
to terminals Q1, Q2 and Q3.
RDG160 has a DC 0...10 V output for electronically commutated (ECM) fan
motors. The switching points can be set via parameter P55...P57.
Q [%]
100
100 0
w
S
Y [%] Fan
H
x
XpH
dz
The diagram only shows the PI controller's proportional part.
Fan speed 1 = S
Fmin
Fan speed 2 = half-way between S
Fan speed 3 = S
Fmax
Q [%]
100
Fan III
=
Fan II
=
Fan I
100 0
S
Y [%] Fan
H
Fan operation can be limited to be active with cooling only or heating only, or even
be totally disabled via control parameter "Fan operation" P52.
When fan operation is disabled, the fan symbol on the display disappears and
pressing the fan button has no influence.
This function allows you to use the thermostat on universal applications such as
chilled / heated ceilings and radiator, etc. (see sections 4.7.9 ff).
In automatic mode, a dwelling time of 2 minutes (factory setting) is active. The fan
maintains each speed for at least 2 minutes before it changes to the next speed.
This minimum on-time can be adjusted from 1...5 minutes via parameter P59.
In automatic fan mode and with the room temperature in the dead zone, the control
valve is normally closed and the fan disabled. With the fan kick function, the fan
can be released from time to time at low speed for minimum on-time (see above)
even if the valve is closed.
This function can be used to avoid damage from moisture due to a lack of air circu-
lation, or to allow a return air sensor to acquire the correct room temperature.
RDG100.../RDG110.../RDG140.../RDG160... Basic Documentation
Functions
www.heronhill.co.uk
0 100
S
Y [%]
Fan
C
XpC
and S
Fmin Fmax
0 100
w
S
Fan Y [%]
C
w Room temperature setpoint
Q Fan speed
Y Control demand "Heating"
H
Y Control demand "Cooling"
C
XpH Proportional band "Heating"
XpC Proportional band "Cooling"
X Dead zone
dz
S Switching point fan (P57)
Fan
S ECM fan min. output (P56)
Fmin
S ECM fan max. output (P55)
Fmax
CE1P3076.en
28 May 2009
Fax: 01823 665807