Benchmark 5000-6000 Operation & Maintenance Manual
SECTION 6
– AERTRIM OPERATION
OMM-0118_B
•
GF-203
•
5/9/2019
Technical Support
•
(800) 526-0288
•
Mon-Fri, 8 am - 5 pm EST Page 82 of 148
AERtrim Activation Instructions
1. Record the following information from the unit you wish to activate:
•
The unit’s
Alpha
– Year – Serial Number
, found on the unit’s code plate. For
example, for a unit built in 2017: N-17-0355.
•
O
2
Trim ID
, found in the
O2 Trim Key
in the C-
More Controller’s
Configuration
Menu
(item 33 in Section 2.6).
•
Fixed ID
, found in the
Fixed Key
in the
Configuration
Menu (item 34 in Section 2.6).
2. Contact AERCO Sales Administration with the recorded information. They will provide you
with a license key.
3. Once you have obtained the license key, navigate to the
O
2
Trim Key
in the
Configuration
menu and enter the key. The
O
2
Trim Menu
and AERtrim should automatically enable. If
the display does not change to the
O
2
Trim Menu
, something is wrong with the values
provided to obtain the key, or with the key itself. Double check your numbers and Contact
Sales Administration for another key.
4. The target O
2
%, O
2
upper range, and lower range are at default values but can be changed
as needed. However, you must enable the
Adjust O2 Trgts
option in the O
2
Trim menu
before you can change these settings.
6.3 OPERATION DETAILS
During operation, the AERtrim system will add or subtract a limited amount of voltage to the
value sent to the combustion air blower. The amount of voltage trim depends on the error
between the desired O
2
% (SP-setpoint) and the current reading of the O
2
sensor (PV-process
variable) and also on high and low limits of blower voltage. The total amount of corrective
voltage trim is limited by the controller to insure safe and reliable operation of the system.
The AERtrim system has a rolling active/inactive operation based on 4 hours on / 10 hours off
sequence. Since this is a trim function and not an active control function, the trim activity can
make adjustments in the blower voltage calibration values on the 4/10 schedule to effectively
control the air/fuel mixture without continuous operation of the sensor. This method achieves
the objective for long term efficiency of boiler operation while maximizing the sensor life in the
boiler environment. The 14 hour cycle insures that the 4 hour on period will be active for any
hour of the day every four days as shown below.
Figure 6-2:
Active O
2
Sensor Cycle Coverage Chart
