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Siemens Building Technologies Basic Documentation LMV5... CC1P7550en
HVAC Products 19 Addendum 4: LMV52... with O2 trim control and O2 module 13.08.2004
19.6.2 Checking the O2 content (20.9 %)
Every time the burner is started up, the measured residual oxygen content is compared
with the O
2 content of the ambient air at the end of prepurging.
For that purpose, the prepurging time of the LMV52... must be param-
eterized such that the combustion chamber and the flueways will be
completely purged.
Normally, this value reads 20.9 %, but it can be parameterized in the case of plants that
operate with enriched air. This test detects offset errors of the measuring cell. For this
reason, the correct setting of the air’s O2 content is safety-related.
Parameter: O2 Content Air
If the O
2 content lies outside the tolerance band of ±2 %, one of the following reactions
will take place, depending on the parameterization of «O
2Ctrl/Guard»:
Parameter: O2Ctrl/Guard (auto deact / man deact / O2-guard / O2-control /
conAutoDeac)
man deact
(auto deact):
O2 trim controller and O2 monitor are deactivated. No O2 test will be
made.
O2-guard / O2-
control:
O2 trim controller / O2 monitor is / are activated. If the test is nega-
tive, safety shutdown will take place, followed by a repetition if possi-
ble, otherwise lockout.
conAutoDeac: O2 trim controller and O2 monitor are activated. Option is «automatic
deactivation». If the test is negative, both the O2 trim controller and
the O2 monitor will be deactivated. The burner will be started up with-
out O2 trim control.
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