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Building Technologies
Boiler Sequence Controller RMK770
CE1P3132en
HVAC Products
7 Boiler control
23.04.2009
If the control’s response is too ”hefty” so that it overshoots or starts oscillating, setting
parameters Xp, Tn and Tv must be increased in a stepwise fashion. A new readjust-
ment should be made only after the control action resulting from the previous readjust-
ment is completed.
t
TBo
TBoSetp
31
32
D
11
1. Reduce Xp in steps of about 25% of the previous value.
2. Increase Tv in steps of 2 to 5 seconds.
If this is not sufficient:
3.
Increase Tn in steps of 10 to 20 seconds.
7.8.5
External burner control
The RMK770 delivers a DC 0…10 V signal as a boiler temperature setpoint for an
external boiler temperature controller.
Main menu > Commissioning > Settings > …
or
Main menu > Settings > Outputs > Setpoint comp boiler
…
Operating line
Range
Factory setting
Setpoint at 0 Volt
–150…50 °C
0 °C
Setpoint at 10 Volt
50…500 °C
100 °C
Limit value
0…140 °C
10 °C
Using setting parameters, the DC 0…10 V output can be matched to the receiver of the
heat demand signal. For setpoints below the limit value, the modulating output delivers
a signal of DC 0 V.
7.9
Protective boiler functions
Main menu > Commissioning > Settings > …
or
Main menu > Settings > Boiler > Limitations
Operating line
Range
Factory setting
Boiler temperature max
25…140 °C
95 °C
Boiler temperature min
8…140 °C
10 °C
Optimization min boiler temp
On / Off
On
Boiler return temperature min
---- / 8…140 °C
---- °C
Bypass pump switching diff
1…20 K
6 K
Cons overrun time
0…60 min
6 min
Frost protection (release input off)
On / Off
On
Frost prot boiler pump
On / Off
On
Protective boiler startup
On / Off
On
Protective boiler startup
Pump on / Pump off
Pump on
Delta boiler temp max (stage 2)
0…10 K
1 K
Control action is
too fast
Setpoint compensation
Settings
