Control Of Modulating Burners - Siemens Synco 700 Basic Documentation

Recommended values for
modulating burners
Building Technologies
HVAC Products
6.5.4

Control of modulating burners

Main menu > Commissioning > Settings > ... or
Main menu > Settings > Boiler > Burner modulating
Operating line
Actuator run time
P-band Xp
Integral action time Tn
Derivative action time Tv
Modulating burners only modulate above a certain level. For standard forced draft
burners, this level is at about 30 to 40 % of the rated capacity.
When the demand for heat is small, the basic stage cycles. When the demand for heat
increases, the 3-position output or a DC 0...10 V output is used to control the combus-
tion air damper.
At the same time, the amount of fuel supplied will also be increased, typically via an
additional switch on the air damper, or by simultaneous control of the amount of fuel
(gas / air ratio).
P M BV OH Q...
M
SA LK
Basic design of a forced draft burner
BV Fuel valve(s)
ACC Combustion air damper, fixed or motorized
M Fan
OH Oil preheater; located between nozzle and adjustable head with small light-oil burners, separate unit in the
case of large heavy-oil burners
P Oil pump, coupled to fan motor
Q... Flame detector
SA Electromotoric air damper actuator
Z Ignition transformer
The functioning with regard to activation and deactivation of the basic stage corre-
sponds to that of 2-stage burner operation. Release of modulation is analogous to the
release of the second stage.
The parameters used for the release and reset integral are the same as those used for
the 2-stage burner. Compared to the 2-stage burner, the release integral should be
selected smaller however (because in this case, it is not the entire capacity of stage 2
that is switched on, but only the modulating part that is released), and the reset integral
can be selected greater.
Release integral stage 2 or modulation: 10 K×m
Reset integral stage 2 or modulation
Locking time stage 2 or modulation
The locking time of stage 2 or modulation must be matched to the type of burner.
This ensures that the burner will always run in its basic stage for a minimum period of
time.
On burner startup and release of the basic stage, the controller drives the damper
actuator towards the fully closed position for a certain period of time. This ensures that,
after the burner startup sequence (prepurging, ignition, stabilization of flame, etc.), the
Modular Heating Controller RMH760B
6 Boiler temperature control
Range
1...600 s
1...200 K
0...600 s
0...30 s
z
20 K×m
10 min
Factory setting
60 s
20 K
150 s
20 s
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CE1P3133en
05.02.2007