Siemens AEROGYR RWI65.02 Manual page 7

Preheating time
Disabling of fan speed II at
low outside temperatures
Fixed preset damper
position
Periodic pump run
(pump kick)
Forced runup and
rundown time for fans
Supervision
Siemens Building Technologies
Landis & Staefa Division
This function prevents freeze-ups of the hot water heating coil at low outside tempera-
tures (especially in plants that use on/off dampers).
The period of time preheating is active can be adjusted from 0 s to 10 min.
When the plant is switched on, first, only the hot water circulator (Q13 / Q14) is activated
while the hot water valve (Y10) is fully open.
To protect the plant, fan speed II is disabled when outside temperature are very low. At
what outside temperature this function is activated depends on the value set (adjustable
from −50 °C to +150 °C). To prevent the controlled system from oscillating at greatly
varying outside temperatures, the RWI65.02 operates with a fixed hysteresis of 2 Kelvin.
This function is used in connection with outside air handling to save energy
(predominently in rooms with low occupancy levels).
The damper sequence (Y30) with operating action « / » is not implemented as a control
sequence. During plant operation, the damper is preset to a fixed position. The fixed
value of the manipulated variable for the air dampers is adjustable from 0 to 100 %
(Y30 minimum limitation).
•
For the hot water pump (DIL switch no. 8 must be in position «Hot water heating
coil»).
To avoid damage during plant off times, there are three setting choices available:
-
the pump is permanently activated;
the pump is activated for 30 s at 24-hour intervals after the last operation, or
-
the pump runs continuously when the outside temperature is below 5 °C; the
minimum pump running time (adjustable from 0 s to 30 min) is maintained
-
the pump is periodically activated, that is, the pump is activated for 30 s after the
last operation according to the selected time (adjustable from 5 min to 24 h)
•
For the chilled water pump.
To avoid damage during plant off times, it is possible to select periodic pump run. If
this function is enabled (selectable), the pump will be activated for 30 s every after-
noon at 15.00.
•
Forced runup.
The fan is always started via the first speed. If the second speed is selected right from
the start, the first speed is first activated.
Switching to the second speed takes place only when the set time has elapsed
(adjustable from 0 to 5 min).
•
Rundown time.
When switching down from the second to the first speed, the RWI65.02 deactivates
the second speed, and the first speed is activated only when the preset time has
elapsed (adjustable from 0 s to 5 min).
•
In plants that use hot water heating coils:
-
continuous checkback signals on the operational status of the plant and on the
status of the hot water circulator, based on the signals received from supervisory
elements such as flow switch and overload protection
-
continuous supervision of risk of frost
-
switching on and off depending on the selected alarm priority («A» or «b»)
•
In plants that use electric heater batteries:
-
continuous checkback signals on the operational status of the plant and, especially,
on that of the electric heater battery, based on the signals received from supervisory
elements such as flow switch, overload and overtemperature protection
-
switching on and off depending on the selected alarm priority («A» or «b»)
CM2N3204E / 1.1999
7/20