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Siemens Building Technologies
Basic Documentation RVP540 / RVP550
CE1P2488en
HVAC Products
Description of the heating engineer settings
18.10.2002
4.228 Type of d.h.w. demand
•
Possibility of using a d.h.w. storage tanks equipped with a control thermostat
Defines the type of d.h.w. control (via d.h.w. sensor or control thermostat).
Setting range
Unit
Factory setting
0 / 1
–
0
By making this setting, the controller takes into account the signal fed to it by the d.h.w.
sensor connected to terminal B3. Entry:
0:
Sensor: the temperature measured with the sensor connected to terminal B3 is
used for the control of the d.h.w. temperature.
1:
Control thermostat: the switching status of the control thermostat connected to
terminal B3 is used for the control of the d.h.w. temperature.
The contacts of the control thermostat must be suited for extra low voltage (gold-
plated)!
When using solar collectors, the use of temperature sensors is
mandatory
(acquisition
of temperature differential between collector and storage tank).
For the transfer of heat from one storage tank to another (d.h.w. partial diagrams7
through 10 or auxiliary function 3), temperature sensors
are required
as well (acquisi-
tion of temperature differential).
When using a d.h.w. sensor:
The controller calculates the switching points with the respective switching differential
from the d.h.w. temperature setpoint entered.
Sensor / line with a short-circuit
= error message
Sensor value available
= d.h.w. according to the current setpoint
Sensor / line with a cut short-circuit = error message
When using a d.h.w. control thermostat:
The controller takes into consideration the switching statuses of the control thermostat.
Line / terminal with short-circuit
= d.h.w. charging ON
Line / terminal with open-circuit
= d.h.w charging OFF
Contact resistance too high
= error message from the thermostat
When using a d.h.w. control thermostat, reduced operation is not possible.
•
The nominal d.h.w. temperature setpoint (operating line 26) must be equal to or
higher than the setpoint adjusted on the control thermostat (thermostat is calibrated
at switch-off point)
•
Boost of the flow temperature setpoint (setting on operating line 776) must be mini-
mum of 10 °C (has an impact on the charging time)
•
In that case, frost protection for d.h.w. is not ensured
Benefit
Description
Setting
Effect
Important
Difference
Note
Important when using
a d.h.w. thermostat
