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Building Technologies
Boiler sequence controller RMK770
CE1P3132en
HVAC Products
9 Precontrol
23.04.2009
Main menu > Commissioning > Settings > …
or
Main menu > Settings > Primary controller > Limitations > Pulse limitation
Operating line
Range
Factory setting
Meter input
---- / 1…4
----
Type of limitation
Absolute / Scaled
Absolute
Limit value
5…4000 pulses/min
75 pulses/min
Integral action time Tn
0…255 min
60 min
The meter input is an input of function block “Meters“ that is used for pulse limitation.
Only inputs configured to a terminal can be selected.
There are 2 types of limitation:
•
Absolute:
Limitation becomes active when the limit value is crossed
•
Scaled:
The limit value is fixed at 75 pulses/min. It can be changed, but the change
has no impact.
If fewer than 5 pulses/min are received, fault status message ”No pulse signal meter
1” (or meter 2, 3 or 4) will be delivered after 20 seconds.
From the limit value, pulse limitation starts throttling the actuating device (mixing valve).
This setting takes effect only with absolute limitation. In the case of scaled limitation,
the limit value can be changed, but the function works with 75 pulses/min (fixed value).
The setting determines the rate at which the flow temperature is reduced:
•
Short integral action times lead to faster reductions
•
Long integral action times lead to slower reductions
9.8.5
Pump overrun and mixing valve overrun
To protect the boiler against overtemperatures after the burner has shut down (when
there are no more heat consumers drawing heat), an overrun time for the consumers
can be set on the boiler controller.
When the burner shuts down, the overrun time ensures that the heating circuits and
DHW heating still draw heat for that period of time, provided they needed heat up to 1
minute before the burner was shut down. In any case, pumps and mixing valves have an
overrun time of 60 seconds.
With primary controller type 1, the mixing valve maintains the former setpoint during the
overrun time and the pump runs; with primary controller type 2, only the pump runs during
that period of time.
9.8.6
Pump kick and valve kick
The pump kick is a protective function that is carried out periodically. It prevents pumps
and/or mixing valves from seizing after longer off periods.
For more detailed information, refer to section 5.5 “Pump kick and valve kick”.
9.9
Text designation
If desired, the primary controller can be assigned specific text. In that case, the selected
text appears on the menu and the info display.
Main menu > Commissioning > Settings > …
or
Main menu > Settings > Primary controller
Operating line
Range
Factory setting
Primary controller
Max. 20 characters
Primary controller
Settings
Meter input
Type of limitation
Limit value
Integral action time Tn
Primary controller