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Building Technologies
Boiler Sequence Controller RMK770
CE1P3132en
HVAC Products
7 Boiler temperature control
01.03.2005
Using this setting, the boiler is always maintained at the minimum boiler temperature.
When using this setting, the boiler is operated at the minimum boiler temperature
whenever there is a heat requisition from one of the heat consumers. When there is no
heat requisition, the boiler temperature can drop below the minimum boiler tempera-
ture.
In case of the “Summer setting, the boiler is maintained at the minimum boiler tempera-
ture only when the boiler has identified summer operation. The change to summer
operation takes place at midnight if, previously, the boiler has received no heat requisi-
tion from the heating circuits
for 48 hours. A heat requisition from DHW heating will be
accepted, however.
The boiler also identifies summer operation if, for more than 48 hours, it has received
no valid boiler temperature setpoint from the boiler sequence manager, or when the
composite outside temperature has exceeded the outside temperature limit.
7.9.6
Protection against boiler overtemperatures
To protect the boiler against overtemperatures on burner shutdown because there may
be no more consumers drawing heat, a consumer overrun time can be set for each
boiler.
Main menu > Commissioning > Settings > …
or
Main menu > Settings > Boiler … > Limitations
Operating line
Range
Factory setting
Consumer overrun time
0…60 min
6 min
After the burner has shut down, the overrun time ensures that the heating circuits and
DHW heating still draw heat for that period of time provided they were consuming heat
up to 1 minute before the burner was shut down. In any case, pumps and mixing valves
observe an overrun time of 60 seconds. For more detailed information, refer to section
5.4 “Pump overrun and mixing valve overrun”.
The overrun time also applies to the boiler pumps and shutoff valves (including the
mixing valve for the maintained boiler return temperature).
7.9.7
Pump kick and valve kick
The pump kick is a protective function that is carried out periodically. It prevents pumps
and / or valves from seizing after longer off periods. For more detailed information, refer
to section 5.5 “Pump kick and valve kick”.
7.9.8
Frost protection for the plant with boiler pump
Here, it can be selected whether frost protection for the plant shall act on the boiler
pump. For detailed information about frost protection for the plant, refer to section 5.3
“Frost protection for the plant”.
7.9.9
Frost protection for the boiler
Supervision of the boiler temperature prevents the boiler from freezing up.
When the boiler temperature drops below 5 °C, the burner is switched on; when it re-
turns to a level above SD (minimum boiler temperature plus switching differ-
ential), the burner will be switched off again.
Without boiler shutdown
Automatic boiler shut-
down
Summer