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Building Technologies Basic documentation LMV37.4... CC1P7546en
HVAC Products 9 Electronic air-fuel ratio control 01.12.2009
9.3.2 Running speed / maximum curve slope
The time required to modulate from low-fire to high-fire is 32 seconds.
In connection with the actuator’s ramp in the basic unit, the following maximum position-
ing angles or speed changes between 2 curvepoints can be covered:
Type of actuator Positioning speed Positioning angle
Electromotoric actuator 5 s / 90° 31°
VSD 5 s / 100% 40%
10 s / 100% 20%
20 s / 100% 10%
No. Parameter
522
Ramp up
523
Ramp down
The setting also acts outside the running position (refer to subsection
Running speed).
VSD
Between the ignition time (P0) and the low-fire point (P1), a speed differential of up to
40% can be set for the VSD, independent of the selected ramp. This means that the pe-
riod of time from ignition to low-fire can vary between 4…16 seconds (5 to 20 seconds
ramp).
Error
code
Diagnostic
code
Meaning for the LMV37.4... system
84 Bit 0
Valency 1
VSD: Curve too steep in terms of the ramp rate
Bit 1
Valency 2..3
Fuel actuator: Curve too steep in terms of ramp speed
Bit 2
Valency 4..7
Air actuator: Curve too steep in terms of ramp speed
The parameterized curve is steeper than permitted with the selected actuator speed.
9.3.3 Entering the running position
The burner is ignited when ignition position
P0 is reached. When entering operating pha-
se
60, the actuators follow the defined curves until the low-fire position is reached
(20% or parameter 545).
9.3.4 Running position
As demanded by the load controller, the actuators are driven along the defined 20% and
100% curves. Point of ignition
P0 can only be reached via the curve setting.
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