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Building Technologies
Basic Documentation LMV27...
CC1P7541en
7 Basic unit LMV27
17.12.2018
7.3.9
Gas / oil pressure switch-max / oil pressure-max or POC
contact, start release oil X5–02
Input for connection of a pressure switch-max for gas or oil: The pressure switch must
have an NC contact, which means that the contact opens when the adjusted maximum
pressure is exceeded. If the plant does not require a pressure switch-max, a wire link
must be fitted between pin 2 and 3.
Caution!
The OEM must check to see whether the burner can be operated without
pressure switch-max. This may necessitate a special approval, depending on
the type of application.
LMV...
Bild 279e/1010
X5
-0
2
Pmax/POC
Protective earth (PE)
Pressure switch-max or POC
“L” for pressure switch
Figure 20: Gas pressure-max / oil pressure switch-max or POC X5-02
The connection facility can also be used as POC (proof of closure) (refer to chapter
Sequence diagrams
).
No. Parameter
237
Gas: Input pressure switch-max / POC
1 = pressure switch-max
2 = POC
3 = pressure switch valve proving
4 = not uses
Note
If the input is used for POC or pressure switch, pressure switch-max can be included
in the safety loop. In that case, pressure switch-max must not be fitted between the
valves, but downstream from them.
Gas pressure switch-max
In all types of gas trains, the maximum gas pressure is monitored from phase 40. If the
maximum gas pressure is exceeded, the system initiates lockout.
Error
code
Diagnostic
code
Meaning for the LMV27
14 0
POC
open
1 POC
close
21
0
Pressure switch-max: Maximum gas pressure exceeded
POC: POC open (software version
V02.00)
1
POC close (software version
≤
V02.00)
During the safety times, the signal from pressure switch-max is only assessed after a
certain period time has elapsed in order to ignore the pressure shocks that occur the
moment the valves open.
No. Parameter
229
Gas: Time to respond to pressure faults in the first and second safety time