Table of Contents
Advertisement
Control of the intermedi-
ate circuit pump
Control of the storage
tank charging pump
Siemens Building Technologies
HVAC Products
cases. Incorrect settings only have an impact at extremely low outside temperatures;
these are small however.
The power factor of the variable speed pump at minimum speed is to be set on operat-
ing line 60.
If, with plant types 2–x, 3–x and 4–x, the common flow temperature is not reached, the
speed of the heating circuit pump will not change because speed control only acts on
the heating circuit pump.
The intermediate circuit pump operates at maximum speed until the limit of maximum
return temperature limitation is exceeded. Then, the pump speed is continuously re-
duced, giving the heating water more time to transfer its heat to the storage tank.
The intermediate circuit pump is controlled according to the signal received from the
closest return sensor. The following setpoints and actual values are used:
Plant type Actual value
(sensor)
2–1, 3–1,
B71
2–2
1–3, 1–9
B71
4–9
B72
*
Setting value operating line 176
**
Setting value operating line 177
The d.h.w. flow temperature setpoint should be maintained as accurately as possible,
allowing the storage tank can be fully charged in one go. At the beginning of d.h.w.
heating, the storage tank charging pump starts at minimum speed until the d.h.w. flow
temperature setpoint is reached. Then, the pump speed is continuously increased. Dur-
ing the charging process, the storage tank charging pump reduces its speed only if
there is not sufficient heat available.
The storage tank charging pump is controlled according to the d.h.w. flow temperature
acquired with sensor B3; setpoint is the current d.h.w. temperature setpoint.
Basic documentation RVD240
11 Function block Plant configuration
Setpoint
[Maximum setpoint of the return temperature during d.h.w.
heating*] minus [differential to the primary limit value with
maximum limitation of the secondary return temperature**]
Maximum setpoint of the return temperature with d.h.w.
heating
39/126
CE1P2384en
27.05.2004
Advertisement
Table of Contents
