Air Pressure Switch Terminal X3-02; Input Gas Pressure Switch-Min - Siemens LME71 Series Basic Documentation

Behavior in the event gas
pressure switch-min fails
(terminal X5-01 pin 2 and pin
3)
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10.2.3 Air pressure switch terminal X3–02
Input for connection of an air pressure switch. Air pressure is anticipated when the fan
is switched on. If there is no air pressure signal, the system initiates lockout. The air
pressure switch must have an NO contact.
If no air pressure switch is required (e.g. when firing on oil), a wire link to the fan output
must be fitted (terminal X3-02 pin 1 to terminal X2-01 pin 3).
Caution!
The OEM must check to see whether the burner can be operated without air
pressure switch. This may necessitate a special approval, depending on the
type of application.
"L" for air pressure switch (LP)
Air pressure switch (LP)
Figure 15: Air pressure switch terminal X3-02

10.2.4 Input gas pressure switch-min

If gas pressure switch-min fails, safety shutdown is triggered and startup prevented
until gas pressure switch-min closes again. During start prevention, the yellow LED is
lit, and the safety circuit is active. The LME7 is in phase 90.
Basic Documentation LME7...
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24.07.2020