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Building Technologies
Basic Documentation LMV27...
CC1P7541en
9 Connection to load controllers
17.12.2018
Shifting multistage operation (OPEN pin 3 / CLOSE pin 2)
Using a simple thermostat, a modulating burner can be operated in shifting 2-stage
mode. In that case, there must be a firm connection between terminal CLOSE and the
live conductor (
L),
and terminal OPEN must be connected to the thermostat or the load
controller.
If OPEN is inactive, the active CLOSE terminal drives the burner to low-fire.
If OPEN becomes active, priority is given over terminal CLOSE so that the output is
increased by driving the burner to high-fire.
LMV...
7546z203e/0913
X5-0
3
L
ON/OFF
Load controller (LR) (OPEN)
Load controller (LR) (CLOSED)
Load controller (LR) (ON/OFF)
Figure 62: Shifting multistage operation (OPEN pin 3 / CLOSE pin 2)
Parameter 205 is needed to interchange usage of the load controller contacts for
multistage operation. In that case, the burner switches to the third stage when input
Stage 2
is active (load controller OPEN). This has no impact on modulating operation.
No. Parameter
205
Function
Load controller contacts multistage
0 = standard
1 = stages interchanged
Modulating
Standard
Stages interchanged
X5-03 pin 1
ON / OFF
Low-fire
Low-fire
X5-03 pin 2
Close
Signal Close
Signal Close
X5-03 pin 3
Open
Signal Open
Signal Open
2-stage
Standard
Stages interchanged
X5-03 pin 1
ON / OFF
Stage 1
Stage 1
X5-03 pin 2
Close
Stage 2
Stage 1
X5-03 pin 3
Open
Stage 2
Stage 2
3-stage
Standard
Stages interchanged
X5-03 pin 1
ON / OFF
Stage 1
Stage 1
X5-03 pin 2
Close
Stage 3
Stage 2
X5-03 pin 3
Open
Stage 2
Stage 3