Mode Of Operation Without Outside Sensor; Frost Protection For The Heating Circuit Flow; Flow Alarm; Heating Circuit And D.h.w. Circuit With Storage Tanks - Siemens RVD230 Basic Documentation

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23.3.3 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 activated for 10 minutes at 6-hour intervals.
2. If the flow temperature falls below 5 °C, the heating circuit pump will be activated
and runs continually.
When active, the respective frost protection stage will be switched off when the flow
temperature has exceeded the limit value by 1 K.

23.3.4 Frost protection for the heating circuit flow

In addition to frost protection for the plant through activation of the heating circuit pump,
frost protection for the heating circuit flow is active. This frost protection is single stage
and will be activated when the heating circuit flow drops below 5 °C. The switching
differential is 2 K; switching off takes place at >7 °C. Frost protection for the heating
circuit flow generates a demand for heat (flow temperature setpoint) of 10 °C and, after
reaching the switch-off criterion, will be active for a minimum of 5 minutes.
With plant types 0–x, there is no frost protection for the heating circuit pump; these
types of plant are used for d.h.w. heating only.
23.4

Flow alarm

23.4.1 Heating circuit and d.h.w. circuit with storage tanks

The purpose of this function is to detect bottlenecks in the heat supply of the district
heat network.
The flow alarm triggers an error message when the flow temperature in the
• heating circuit
• precontrolled or common flow
• the d.h.w. circuit
does not reach the setpoint band (setpoint ± switching differential of 3 °C) within a
defined period of time when there is demand for heat. This period of time can be set on
operating line 143. The flow alarm can be deactivated by entering --:-- .
The flow alarm becomes inactive as soon as the setpoint band is reached.
The flow alarm appears on the display as ERROR and, on operating line 50, with an
error code.
The correlation between sensor, plant type and error code is the following:
Control
Primary controller
Common flow
Heating circuit controller
Heating circuit
controller
D.h.w. controller
Basic Documentation RVD230
23 Function block Device functions
Plant type
5–x, 6–x, 7–2
2–x, 3–x
1–x
3–x, 7–2
x–2, x–7, x–8, x–10, 2–12
Sensor Error code
B1 120
B1 120
B1 121
B12 121
B3 123
CE1P2383en
27.05.2004