Benchmark Platinum-Edge [II]: Operation-Service Manual
SECTION 9
– AERTRIM OPERATION
OMM-
0137_E • GF-211 • 12/13/2019 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST Page
128
of
153
Once the system operational stability conditions are met, the AERtrim system will execute the
following steps:
1. Lock the fire rate at the current position that needs adjustment to the air/fuel ratio.
2. The
Demand
LED will flash once per second
to indicate that the trim function has started.
3. Check the oxygen levels inside the combustion chamber:
•
If oxygen levels are within the set range, AERtrim releases control.
•
If oxygen levels are outside the set range, AERtrim will adjust Blower Voltage to bring
the boiler back to the Target O
2
value.
This process repeats until the target oxygen range is achieved or the unit reaches the allowable
blower voltage limit.
9.4 AERtrim O
2
SENSOR AUTO CALIBRATION
AERtrim includes an automatic O
2
sensor calibration feature, which helps maintain oxygen
sensor readout accuracy.
When sensor calibration occurs, the controller starts the O
2
Cal Purge for 40 seconds (55
seconds on the BMK5000 & 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
2
% level of 20.9%. If the calculated offset is more than ± 3%,
O
2
Warning Service Required
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
control on the
Controller’s
O2 Sensor
screen
(
Main Menu
→
Calibration
→
Input/Output
→
O2 Sensor
).
Auto Calibration
is disabled by default but is enabled during AERtrim activation (see Section
9.2, above). You can also use the
Calibration Frequency
,
Time
and
O2 Offset
parameters to modify calibration frequency and time of day and enter an offset to the O
2
reading
from the
O2 Sensor
screen.
9.5 AERtrim MENU VALUES and DEFAULTS
There are three AERtrim screens, available from
Main Menu
→
Advanced Setup
→
Performance
→
AERtrim
.
•
AERtrim Settings
: To enable AERtrim, set the
AERtrim
parameter to
Enabled
. You
can then adjust the
O2 Offset
,
Settle Time
,
Trim Gain
and
Trim Iteration
Limit
parameters to values appropriate for the unit, per the tables below.
•
O2 Trim Parameters
: Choose a
Valve Position
and then set the
O2 Target
,
Upper
and
Lower Limits
for the valve position. You can then repeat this for all other
valve positions, per the tables below
•
AERtrim Status
: Displays the current status of AERtrim operation.
For more information, see the
Edge Controller Manual
(OMM-0139, GF-213), Section 6.6.1.
