Siemens RDG400 Basic Documentation page 16

Remote heating/
cooling changeover
External / return air
temperature sensor
Floor heating
Floor temperature
limitation function
Recommended values
for P51:
External temp.
Parameter P51
sensor available
OFF No
OFF Yes
10...50˚C No
10...50˚C Yes
Dewpoint monitoring
16 / 42
Siemens
Building Technologies
The QAH11.1 cable temperature sensor for automatic heating / cooling changeover
can be replaced by an external switch for manual, remote changeover:
X2
M
T °C
The sensor or switch can be connected to input terminal X2 (factory setting) or X1
or D1 (switch only), depending on the commissioning of the inputs (P38, P40, P42).
See also section 4.9 "Multifunctional input".
The thermostat acquires the room temperature via built-in sensor, external room
temperature sensor (QAA32), or external return air temperature sensor (QAH11.1)
connected to multifunctional input X1 or X2.
Inputs X1 or X2 must be commissioned accordingly. See section 4.9 "Multi-
functional input".
Application "Single-duct and radiator" can also be used for floor heating.
The temperature should be limited for 2 reasons: comfort and protection of the
floor. It is only available with application "Single-duct and radiator".
The floor temperature sensor, connected to multifunctional input X1 or X2, acquires
the floor temperature. If the temperature exceeds the parameterized limit
(parameter P51), the heating valve is fully closed until the floor temperature drops
to a level 2 K below the parameterized limit.
This function is factory-set to OFF (disabled).
Input X1 or X2 must be commissioned accordingly (P38 or P40 = 1).
See section 4.9 "Multifunctional input".
Living rooms:
Up to 26 °C for long-term presence, up to 28 °C for short-time presence
Bath rooms:
Up to 28 °C for long-term presence, up to 30 °C for short-time presence
The table below shows the relation between parameter, temperature source and
temperature display:
Source for display of room
temperature
Built-in sensor
External temp. sensor
Built-in sensor
Built-in sensor
If the thermostat is used for chilled ceiling, dewpoint monitoring is essential to
prevent condensation. It helps avoid associated damage to the building.
A dewpoint sensor with a potential-free contact is connected to multifunctional input
X1, X2 or D1. If there is condensation, the cooling valve is fully closed until no
more condensation is detected, and the cooling output is disabled temporarily.
The condensation symbol
The input must be commissioned accordingly (P38, P40, P42).
See section 4.9 "Multifunctional input".
RDG400 Basic Documentation
Functions
X2
T
M
QAH11.1 3076Z03
Output control according
to
Built-in sensor
External temp. sensor
Built-in sensor
Built-in sensor + limit by
external sensor
is displayed during temporary override.
Contact open heating mode
Contact closed cooling mode
Floor temp. limit
function
Not active
Not active
Not active
Active
CE1P3182en
19 Jun 2009