Test Of H-Contacts; Auxiliary Functions; Frost Protection For The Plant; Flow Alarm - Siemens RVL481 Basic Documentation

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25.3.4 Test of H–contacts
The connected H–contacts can be checked on operating line 164. It is always the cur-
rent status that is indicated (contact open, contact closed).
The contacts can be individually selected by pressing
Input Contact
H1 Overriding the operating mode (contact H1)
H3 Operating lock (contact H3)
H4 Minimum limitation of stroke (contact H4)
The contact's status is displayed as follows:
= contact closed
= contact open
25.4

Auxiliary functions

25.4.1 Frost protection for the plant

The plant can be protected against frost. For this purpose, the RVL481 and the heat
source equipment must be ready to operate (mains voltage present!).
The following settings are required:
• The outside temperature at which frost protection shall respond
• The minimum flow temperature that shall be maintained by the frost protection function
0.5 °C 0.5 °C
ON
OFF
OpL 167
OpL167 Operating line 167
TA Outside temperature
OFF Frost protection OFF
ON Frost protection ON
If the outside temperature falls below the limit value (setting on operating line 167 mi-
nus 0.5 °C), the RVL481 will switch the circulating pump on (pump connected to termi-
nal Q1) and maintain the flow temperature at the selected minimum level.
The control is switched off when the outside temperature exceeds the limit value by
0.5 °C.
Frost protection for the plant can be deactivated.

25.4.2 Flow alarm

The fault alarm triggers an error message if the flow or boiler temperature does not
reach the required setpoint band (setpoint ± a defined switching differential) within a
defined period of time – provided there is a demand for heat. This period of time can be
set on operating line 171.
• Plant type 1–x, 3–x, 4–x and 6–x: Decisive is the temperature acquired by sensor B1.
The switching differential corresponds to the neutral zone (±1 °C)
• Plant types 2–x and 5–x: Decisive is the temperature acquired by sensor B1. The
switching differential corresponds to the adjusted switching differential of the boiler (±
0.5 × SD; operating line 94)
Heating and D.h.w. Controller RVL481
25 Function block "Service functions and general settings"
T
A
and .
CE1P2541en
20.05.2008