Maximum Limitation Of The Boiler Temperature; Minimum Limitation Of The Boiler Temperature; Protective Boiler Startup - Siemens Synco700 RMK770 Documentation Handbook

Building Technologies
HVAC Products
7.9.1

Maximum limitation of the boiler temperature

This setting provides maximum limitation of the boiler temperature setpoint. For burner
control, this value represents the switch-off point. In this range, the boiler's switching
differential is calculated downward.
Maximum limitation of the boiler temperature is always active. The only exception is the
wiring test.
TBo
80
70
60
50
40
30 0
20 10
HD Heat demand
SDB0 Boiler's switching differential
TBo Boiler temperature
TBoMax Maximum limit of the boiler temperature
TBoMin Minimum limit of the boiler temperature
TBoSP Boiler temperature setpoint
7.9.2

Minimum limitation of the boiler temperature

This setting provides minimum limitation of the boiler temperature setpoint. For burner
control, this value represents the switch-on point. In this range, the boiler's switching
differential is calculated upward.
The point in time the minimum boiler temperature is maintained depends on the boiler
shutdown setting (see below).
When there is a heat requisition, the minimum boiler temperature is always active.
If a minimum return temperature is required, it must be ensured that the minimum boiler
temperature will be set to a level which lies a few Kelvin above the minimum return
temperature.
7.9.3

Protective boiler startup

To protect the boiler against condensation, a minimum boiler temperature is usually
preset. This ensures that, in normal operation, the boiler temperature will not fall below
a minimum temperature.
Main menu > Commissioning > Settings > ... or
Main menu > Settings > Boiler ... > Limitations
Operating line
Protective boiler startup
To prevent the boiler temperature from staying below the minimum temperature for
unnecessary lengths of time, the amount of heat drawn by DHW heating and the heat-
ing circuits can be restricted until the boiler temperature has again risen above the
minimum limit value. Therefore protective boiler startup generates critical locking sig-
nals but only for the lead boiler (for more detailes information, refer to section 5.6 "Heat
demand and load control").
Boiler Sequence Controller RMK770
7 Boiler temperature control
TBoMax
TBoSp
TBoMin
0 -10 -20
Range
On / Off
SDBo
HD
°C
Factory setting
On
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CE1P3132en
01.03.2005