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Siemens Building Technologies
Basic Documentation RVD110, RVD130
CE1P2381E
HVAC Products
11 Function block Space heating
27.05.2004
11.10 Pump control
11.10.1 Pump overrun
Pump overrun can be set for both the heating circuit pump and the d.h.w. pumps (oper-
ating line 72). Setting 0 deactivates pump overrun.
11.10.2 Pump kick
The pump kick function is activated for 30 seconds every Friday morning at 10.00.
If several pumps need kicking, they are activated one after the other in the order of Q1,
Q3 and Q7.
The kicks are separated by pauses of 30 seconds. The pump kick is always activated. It
can be interrupted by signals as a function of the heat generating equipment or the con-
sumers.
With plant types no. 2 and 7, the pump kick of pump Q1 is not executed if d.h.w. pump
Q3 runs.
The pump kick function can be deactivated on operating line 56.
11.10.3 Protection against overtemperatures
In the case of shifting and parallel d.h.w. priority, the pump cycling function is active
with plant types no. 2 through 8.
If, during d.h.w. heating, the common flow temperature exceeds the flow temperature
called for by the heating circuit, the heating circuit pump will be repeatedly switched on
and off . An on / off cycle takes 10 minutes (fixed). The switching ratio is determined by
comparing the setpoint or actual value of the flow temperature with the room tempera-
ture setpoint. The following limit values are used:
•
The minimum on time is 3 minutes. If the calculation produces a shorter on time, it is
extended to 3 minutes
•
The maximum on time is 8 minutes. If the calculation produces a longer on time, the
pump will run continuously
Pump cycling is used as a protection against overtemperatures, but is not a safety func-
tion.
This protection against overtemperatures will be activated if a maximum limit value of
the flow temperature has been entered.
The limit value of the heating circuit is used (setting on operating line 95).
If the flow temperature exceeds the maximum limit value of the flow temperature by
7.5 °C, the heating circuit pump will be deactivated. When the flow temperature has
dropped below that limit, the pump will be activated again for a minimum of 3 minutes.
Switching off of the pump is used as a protection against overtemperatures, but is not a
safety function!
11.11 Maximum limitation of the room temperature
The room temperature can be limited to a maximum value, in which case a room tem-
perature sensor is required (sensor or room unit).
The limit value is generated from the nominal room temperature setpoint plus the value
entered on operating line 74.
When the limit value is reached, the heating circuit pump will remain deactivated until
the room temperature has again dropped below the setpoint.
Maximum limitation of the room temperature acts independent of the setting made for
the room authority.
Cycling of pump
Switching the pump off
