Mode Of Operation With Outside Sensor; Mode Of Operation Without Outside Sensor; Frost Protection For The House Or Building; Mode Of Operation With Room Temperature Sensor - Siemens RVD110 Basic Documentation

Siemens Building Technologies
HVAC Products

11.8.1 Mode of operation with outside sensor

Frost protection for the plant operates in 2 stages:
1. If the outside temperature falls below 1.5 °C, the heating circuit pump will be
switched on for 10 minutes at 6-hour intervals.
2. If the outside temperature falls below –5 °C, the heating circuit pump will be
switched on to run continuously.
The frost protection stage active at a time will be deactivated when the outside tem-
perature has exceeded the limit value by the switching differential of 1 K.

11.8.2 Mode of operation without outside sensor

Frost protection for the plant operates in 2 stages:
1. If the flow temperature (sensor B1) falls below 10 °C, the heating circuit pump will
be switched on for 10 minutes at 6-hour intervals.
2. If the flow temperature falls below 5 °C, the heating circuit pump will be switched on
to run continuously.
The frost protection stage active at a time will be deactivated when the flow tempera-
ture has exceeded the limit value by the switching differential of 1 K.
11.9

Frost protection for the house or building

Frost protection for the house or building makes certain that the room temperature will
not fall below a certain level. It compares the room temperature with the frost protection
setpoint. If the room temperature drops below that level, the controller will maintain a
room temperature equivalent to the frost protection setpoint plus the switching differen-
tial of 1 K, provided both the controller and the heat source are ready to operate (mains
voltage present) and a room temperature sensor or room unit is connected.
The frost protection setpoint is to be set on the end-user level (operating line 3). This
function cannot be deactivated.

11.9.1 Mode of operation with room temperature sensor

The controller compares the room temperature with the adjusted frost protection set-
point. If the room temperature falls below that setpoint, the controller will activate the
heating circuit pump and maintains the flow temperature at that setpoint plus the
switching differential of 1 K.
With the room temperature sensor, frost protection for the building has priority over the
ECO function.

11.9.2 Mode of operation without room temperature sensor

Based on the flow temperature, the controller continuously determines the relevant
room temperature.
If the relevant room temperature falls below the adjusted frost protection setpoint, the
controller will switch the heating circuit pump on and controls the flow temperature such
that the relevant room temperature will lie above the frost protection setpoint by the
amount of the switching differential of 1 K, provided the heating curve slope is correctly
set.
Without the room temperature sensor, frost protection for the building has no priority
over the ECO function.
Basic Documentation RVD110, RVD130
11 Function block Space heating
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CE1P2381E
27.05.2004