HELIX VX-399 Installation, Operation & Maintanance Manual page 36

!
WARNING
Fire, explosion, asphyxiation and electrical shock
hazard. Read this instruction and understand all
requirements, including requirements of authority
having jurisdiction before making adjustments. Failure
to follow these instructions could result in death or
serious injury.
2. Perform combustion test on HIGH fire using calibrated
combustion analyzer. Adjust CO2 to within specifications
by rotating the Throttle Screw, counterclockwise
increase CO2 level, clockwise
See Figure 9-3 and 9-6.
After adjusting CO2 to correct level, verify:
(1) CO PPM level is in specified range and
(2) flame signal is in specified range. See Appendix A
page 76.
CO2 level, CO PPM level, and flame signal for HIGH fire
are given in the following tables.
High Fire Combustion - 399 MBH
Gas
Min.
Natural Gas 9.2
Propane 10.0
3.
Switch to LOW fire in boiler System Test. On user
interface push Enter. "HIGH power" starts flashing.
Scroll down to "Low Power". Push Enter. "Low Power"
stops flashing and becomes solid. Boiler is now locked
in LOW fire.
Adjust Offset Screw slowly and
in small steps, no more than 1/8
of a turn each time. See Figure 9-3 and 9-6.
Perform combustion test on LOW fire using
calibrated combustion analyzer. Adjust CO2 to within
specifications by turning Offset Screw, clockwise
increase CO2 level, counterclockwise
CO2 level. After adjusting CO2 to correct level, verify
(1) CO PPM level is in specified range and
(2) flame signal is in specified range.
CO2 level, CO PPM level, and flame signal for LOW fire
see following tables.
9 - START UP PROCEDURE
to decrease CO2 level.
CO
2
CO
Max.
9.8 <200ppm
11.0 <200ppm
to decrease
FIGURE 9-3 Throttle Screw Location - 399 MBH
to
Throttle Screw
to
36
P/N 240010943, Rev. C [09/07/2016]