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Siemens Building Technologies
Basic Documentation RVD230
CE1P2383en
HVAC Products
17 D.h.w. heating
27.05.2004
17.3.7 Cold water sensor
Cold water sensor B32 is fitted after the mixing point of cold water return and circulation
return. It should be located as close as possible to the mixing point. he sensor detects
temperature changes on the cold water side, which are then included in the flow tem-
perature control. This improves the control performance considerably.
17.3.8 Plant type 8–4
This type of plant uses a solenoid valve in the primary flow of each heat exchanger.
Output Y1 controls the heating circuit valve and output Y2 the d.h.w. valve. A flow
switch is required in the secondary return of the d.h.w. circuit.
When there is a demand for d.h.w., valve Y2 opens until the setpoint at d.h.w. flow
sensor B3 is reached. Valve Y1 remains fully closed.
If there is a demand for heat from both circuits, the d.h.w. circuit is given priority.