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Building Technologies
Boiler Sequence Controller RMK770
CE1P3132en
HVAC Products
7 Boiler temperature control
01.03.2005
In “Auto“ position, the boiler is released and receives its presettings from the boiler
sequence manager.
The boiler is shut down, that is, burner and pumps are switched off.
The boiler is released. The aggregates (shutoff valve, maintained boiler return tempera-
ture with mixing valve, boiler pump) are active, but the burner is still switched off.
The boiler is released and the burner with its stage 1 or basic stage maintains the ad-
justed test mode setpoint.
The boiler is released and the burner with its stages 1 and 2 or basic stage and modu-
lating part maintains the adjusted test mode setpoint.
The boiler is released and the modulating burner operates at the modulation level ac-
cording to the setting made. The burner is switched off when the maximum limit of the
boiler temperature is exceeded.
7.8 Burner
control
If a boiler temperature sensor is configured, control is provided according to that sensor.
Main menu > Commissioning > Extra configuration > Boiler … > Inputs
Operating line
Adjustable values / remarks
Boiler sensor
Assign input
With the programmed types of plant, a boiler temperature sensor is assigned to each of
the 2 boilers. But that sensor can also be removed (---).
Boiler sequence management predefines a boiler temperature setpoint.
Without own boiler temperature sensor, the assumption is made that boiler temperature
limitation is ensured by an external boiler temperature limiter. In that case, control uses
the main flow sensor as the control sensor.
7.8.1 2-position
control of 1-stage burners
For 2-position control with a 1-stage burner, the following variables can be adjusted:
•
Boiler switching differential
•
Minimum burner running time
Main menu > Commissioning > Settings > …
or
Main menu > Settings > Boiler … > Burner
Operating line
Range
Factory setting
Boiler switching differential
1…20 K
6 K
Burner run time min
0…60 min
4 min
The controller compares the actual value of the boiler temperature with the setpoint. If
the boiler temperature drops below the setpoint by half the switching differential, the
burner will be started up. If the boiler temperature exceeds the setpoint by half the
switching differential, the burner will be shut down.
Auto
Boiler Off
Pump on (burner off)
Stage 1 controlled
Stages 1 + 2 controlled
Modulating fixed
Boiler switching
differential