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Benefit
Description
Setting
Effect
Important
Difference
Note
Important when using
a d.h.w. thermostat
242/348
Siemens Building Technologies
HVAC Products
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
0 / 1
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
Sensor value available
Sensor / line with a cut short-circuit
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
Line / terminal with open-circuit
Contact resistance too high
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
Basic Documentation RVP540 / RVP550
Description of the heating engineer settings
Unit
–
= error message
= d.h.w. according to the current setpoint
= error message
= d.h.w. charging ON
= d.h.w charging OFF
= error message from the thermostat
Factory setting
0
CE1P2488en
18.10.2002
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