Aertrim O 2 Sensor Auto Calibration - Watts Aerco Benchmark Series Operation And Service Manual

Benchmark Platinum-Edge: Operation-Service Manual
SECTION 9 – AERTRIM OPERATION
9.4 AERtrim O SENSOR AUTO CALIBRATION
2
AERtrim includes an automatic O sensor calibration feature, which helps maintain oxygen
2
sensor readout accuracy.
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
O % level of 20.9%. If the calculated offset is more than ± 3%, O Warning Service Required
2 2
message is displayed, and the trim function is disabled.
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 calibration can be initiated by enabling the Auto Calibrate Now toggle on the
Controller's Oxygen Sensor screen (Main Menu  Calibration  Input/Output  Oxygen
Sensor).
Auto Calibration is disabled by default but is enabled during AERtrim activation (see Section
9.2, above). Calibration frequency and time adjustments can be modified from the Auto Cal
Freq and the Auto Cal Time setting, available on the Controller's AERtrim Settings screen (go
to: Main Menu  Advanced Setup  Performance  AERtrim  AERtrim Settings).
OMM-0137_D • GF-211 • 7/16/2019 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST Page 122 of 146