AERCO BMK 3.0 LN Nat. Gas APRIL 2009 - Manual (Page 121)

APPENDIX K
K-3
14. If necessary, adjust the iris air damper
shown in Figure K-2 until the oxygen level is
within the range specified in Table K-1.
15. Once the oxygen level is within the specified
range at 100%, lower the firing rate to 70%.
Figure K-2
Iris Air Damper Location/Adjustment
NOTE
The remaining combustion calibration
steps utilize the Variable Frequency Drive
(VFD) located behind the front door of the
unit. The VFD up (Λ) and down (V) arrow
keys will be used to adjust the oxygen
level (%) at firing rates of 70%, 50%, 30%
and 14% as described in the following
steps. These steps assume that the inlet
air temperature is within the range of 50°F
to 100°F.
16. Locate the Variable Frequency Drive (VFD)
behind the front door of the unit. Refer to the
VFD operating controls shown in Figure K-3.
Figure K-3
VFD Controls and Displays
IMPORTANT
In the following steps, the values
appearing in the right part of the VFD
display for parameters 21, 20, 19, 15
represent the base frequency (Hz) x 10.
For example: a displayed value of 326
corresponds to a frequency of 32.6 Hz.
17. Press the M (Menu) programming key on
the VFD.
18. Using the up (Λ) arrow key, select VFD
parameter 21. The selected parameter will
appear in the left part of the display and the
voltage frequency (Hz) supplied to the
blower will appear in the right part of the
display (see IMPORTANT note above).
19. With the selected VFD parameter display
flashing, press the M key. Code will be
displayed, requesting the valid code to be
entered. Enter code 59 using the arrow
keys.
20. Press the M key again and observe the
frequency shown in the right part of the
display. The oxygen level at the 70% firing
rate should be as shown in the following
tabular listing. Also, ensure that the carbon
monoxide (CO) and nitrogen oxide (NOx)
readings do not exceed the values shown.
Combustion Oxygen Level at
70% Firing Rate
Oxygen %
± 0.2
Carbon
Monoxide NOx
6.0 % <100 ppm <30 ppm