Siemens LMV 5 Series, Technical Instructions, Page: 225 / 374

LMV Series Technical Instructions
Document No. LV5 ‐ 1000
SCC Inc. Page 17 Section 7
AZL Says “ Measurement not Successful ” When Measuring the Delay Time for O2 Trim
When setting the low fire point or the high fire point on the O
2
control curve, the AZL measures
what is called the “delay time” (Tau time). The delay time is defined as the length of time it
takes a change in the air damper position to be detected by the O
2
sensor. This time is longer at
low fire and shorter at high fire due to gas velocity. If an error occurs while trying to measure
this delay time, the AZL says “ Measurement not Successful ”.
To troubleshoot this, check the following:
1) Verify that OptgMode is set to “man deact” using the following menu path:
Params & Display > O2Contr/Alarm > Gas/Oil Settings > OptgMode
2) Verify that LowfireAdaptPtNo is set to 2 (combustion curve point 2) or higher if desired. By
default, this parameter is set to “X” (undefined). The menu path for this parameter is:
Params & Display > O2Contr/Alarm > Gas/Oil Settings > Control Param >
LowfireAdaptPtNo
3) If both of the above parameters are set correctly, then it is possible that the O
2
readings on
the ratio control curve were set incorrectly. When setting each point on the O
2
control
curve, the LMV5 will prompt with the message “When value stable continue w ENTER”.
Pressing ENTER then sets the %O
2
for the ratio control curve. If ENTER is pressed too early
before the O
2
value has stabilized, a non ‐ representative O
2
value will be entered for the
ratio control curve. If this is the case, go back into the O
2
control curve and at each point
wait to get a stable reading before pressing ENTER to ensure that the O
2
reading is
representative of the current air damper position. 30 ‐ 60 seconds is not too long to wait
once the arrow (>) turns into a colon (:) indicating that the actuators have stopped moving.
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