IC-SA-1511 (02/2014)
V/LNV Series Manual
4-1
CHAPTER 4
Adjustments
4.1 — Overview
While each burner is tested at the factory for correct operation before shipment, variable conditions such
as burning characteristics of the fuel used and operating load conditions may require further adjustment
after installation to assure maximum operating efficiency.
Prior to placing the boiler into initial service, a complete inspection should be made of all controls,
connecting piping, wiring and all fastenings such as nuts, bolts and setscrews to be sure that no damage or
misadjustments occurred during shipping and installation.
A combustion efficiency analysis made during the initial start-up will help to determine what additional
adjustments are required in a particular installation.
4.2 — Combustion Adjustment on Gas and Oil
Efficient combustion cannot be properly judged by flame appearance, although it may help in making
preliminary settings.
The proper settings of air-fuel ratios must be determined by flue gas analysis. Combustion gas analysis
indicates the air to fuel ratio and the degree of complete combustion. Instruments are available to measure
carbon dioxide (CO
2
), oxygen (O
2
), and carbon monoxide (CO). At no time should CO
2
measurements alone
be used to indicate proper excess air levels. Only O
2
measurement can definitively show whether sufficient
air has been provided for combustion.
4.2.1 — Stack Temperature
Net stack temperature is obtained by subtracting the ambient temperature from the flue gas temperature. A
high net stack temperature indicates wasted heat. Stack temperature should be as low as possible without
causing flue gas condensation.
Stack heat loss can be reduced by decreasing either the temperature or the volume of the flue gas, or both.
Flue gas temperature is reduced by improving heat transfer or by reducing excess combustion air. A certain
amount of excess air is necessary to complete combustion. More efficient burners require minimum excess
air.