750-392
CBEX-DE
4-13
Startup, Operating, and Shutdown: All Fuels
On ignition failure, the flame failure light will glow and the blower will purge the boiler of unburned fuel vapors
before stopping. After ignition failure, wait a few moments before resetting the lockout switch.
After main flame ignition, the burner should be set on manual control at its low-fire setting (with manual flame
control at “close”) until the boiler is properly warmed. Close the steam header.
In the case of a steam boiler, close the vent valve when the steam begins to appear.
A hot water boiler must have a continuous flow of system water through the vessel during the warm-up period.
The entire water content of the system and boiler must be warmed prior to increasing fuel input.
If the flame at low-fire provides insufficient heat to reach normal operating pressure or temperature after 30 min-
utes, gradually increase the firing rate manually in small increments until an increase is noted in pressure or tem-
perature.
After the boiler is thoroughly warmed, turn the manual flame control to high fire. At this point a combustion anal-
ysis should be made, with instruments, and fuel flow regulated as required. Refer to the combustion setup
instructions in the Hawk controls manual. After making the high-fire adjustment, manually decrease the firing
rate, stopping at each combustion curve point to analyze combustion gases, and adjust as required.
To properly perform the testing and adjusting, it is necessary that the burner be allowed to fire at a maximum
rate long enough to achieve desired results.
4.9.1 — Operating
Normal operation of the burner should be with the controls in automatic mode. Manual mode is provided for ini-
tial adjustment of the burner over the entire firing range. When a shutdown occurs while operating in manual at
other than low-fire, the damper will not be in a closed position, thus allowing more air than desired to flow
through the boiler. The hot flame to cool air cycling subjects the pressure vessel metal and refractory to undesir-
able stresses.
With the controls in AUTO, the burner will operate on a modulating basis according to the load demand.
The burner will continue to operate with modulated firing until the operating limit pressure or temperature is
reached, unless:
1. The burner is manually turned “off.”
2. A low-water condition is detected by low-water level control.
3. The electrical or fuel supply is interrupted.
The burner and control system is designed to provide a “pre-purge” period of fan operation prior to establishing igni-
tion spark and pilot flame. Do not attempt to alter the system or take any action that might circumvent the “pre-
purge” feature. Failure to follow these instructions could result in serious injury or death.
!
Warning
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