Aertrim Auto Calibration - Watts Aerco Benchmark OMM-0117 Operation And Maintenance Manual

Benchmark 5000-6000 Operation & Maintenance Manual
SECTION 6 – AERTRIM OPERATION

6.4 AERtrim AUTO CALIBRATION

AERtrim includes an automatic sensor calibration feature, which helps maintain oxygen sensor
readout accuracy. This feature is disabled by default but may be enabled during AERtrim
activation. Calibration frequency and time adjustments are located in the Auto Cal Freq, and
the Auto Cal Time setting in the O2 Trim menu (see Section 6.5 for details).
Auto Calibration occurs only when the unit is in STANDBY Mode. For example, if the time
and day for an auto calibration passes, the controller will wait for the boiler to cycle off and go
into standby mode before executing the sensor calibration function. If desired, a manual
calibration can be initiated by the user, by enabling the AUTO CAL NOW menu item.
When sensor calibration occurs, the controller starts the O Cal Purge for 40 seconds (55
2
seconds on the BMK 6000) in order to remove residual combustion fumes. Once purged the
controller reads the oxygen level of ambient air used for purging and calculates a calibration
offset between -3 and +3. The offset is applied to correct the sensor reading to the expected air
% level of 20.9%. If the calculated offset is more than ± 3%, "O
O Sensor OOR Maintenance
2 2
Required" will be displayed, and the trim function is disabled. (OOR is used throughout this
manual for Out Of Range)
OMM-0118_B • GF-203 • 5/9/2019 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST
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