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Siemens
RDG400 Basic Documentation
CE1P3182en
Building Technologies
2015-05-20
The QAH11.1 cable temperature sensor for automatic heating/cooling changeover
can be replaced by an external switch for manual, remote changeover:
Contact open
à
heating
mode
Contact closed
à
cooling
mode
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.
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.
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 (4 °F) 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.
Living rooms:
Up to 26 °C (79 °F) for long-term presence, up to 28 °C (82 °F) for short-time
presence
Bath rooms:
Up to 28 °C (82 °F) for long-term presence, up to 30 °C (86 °F) for short-time
presence
The table below shows the relation between parameter, temperature source and
temperature display:
Parameter P51
External temp.
sensor available
Source for display of room
temperature
Output control according
to
Floor temp. limit
function
OFF
No
Built-in sensor
Built-in sensor
Not active
OFF
Yes
External temp. sensor
External temp. sensor
Not active
10...50
˚
C
(50...122
˚
F) No
Built-in sensor
Built-in sensor
Not active
10...50
˚
C
(50...122
˚
F) Yes
Built-in sensor
Built-in limit by
external sensor
Active
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 is displayed during temporary override.
Remote heating/
cooling changeover
External/return air
temperature sensor
Floor heating
Floor temperature
limitation function
Recommended values
for P51:
Dewpoint monitoring
