Boost Of The Flow Temperature Setpoint For D.h.w - Siemens RVA47.320 User Manual

Important
Difference
Note
Important when using a
d.h.w. thermostat
D.h.w. control thermostat
(example)
Benefit
Description
90/166
Siemens Building Technologies
HVAC Products
The contacts of the control thermostat must be suited for extra low voltage (gold-
plated)!
When using a d.h.w. sensor:
The controller calculates the switching points with the respective switching differential
as a function of the d.h.w. temperature setpoint entered.
Sensor / line with a short-
Sensor value available
Sensor / line with a short-
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
When using a d.h.w. control thermostat, reduced operation is not possible.
•
The nominal d.h.w. temperature setpoint (operating line 13) 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 126) must be
minimum of 10 °C (has an impact on the charging time)
•
In that case, frost protection for d.h.w. is not ensured
UEBW >= 10 °C
∆T > 0 °C
SD = 6 °C
UEBW = Boost of the temperature setpoint (setting 126)
TBWw = Nominal setpoint of the d.h.w. temperature (setting on operating line 13)
TRW - SD = setpoint of the thermostat minus the switching differential
TRw = setpoint of the thermostat
4.42 Boost of the flow temperature setpoint for
d.h.w.
•
Efficient d.h.w. heating
To allow the d.h.w. to be heated up, the boiler temperature must be higher than the
d.h.w. setpoint.
Basic Documentation RVA47.320
Description of the heating engineer settings
= fault message
= d.h.w. according to the current setpoint
= no d.h.w.
= error message from the thermostat
70 °C
TBWw + UEBW
TBWw
60 °C
56 °C
TRw
50 °C
TRw - SD
(point of calibration)
CE1P2379E
15.07.2002