CleaverBrooks 4WI, Руководство по эксплуатации, обслуживанию и запасным частям

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750-211 (revised 2009)
Promethean Boilers, Model 4WI Manual 5-3
5.2 — Control Settings: Steam and Hot Water
1.
The operating pressure control of a steam boiler should be set slightly above the highest desired steam pressure,
but at least 10% lower than the setting of the safety valve.
2.
The temperature operating control on a hot water boiler should be set slightly above the highest desired water
temperature and within the limits of the pressure vessel.
Inspect the high limit control for proper setting.
FIGURE 5-2.
Steam Controls and Hot Water Controls
3.
On a high pressure steam boiler, the high limit control should be set approximately 10 psig above the operating
limit pressure control setting, if feasible, or midway between the operating limit pressure and the safety valve
setting. The setting on a low pressure steam boiler may be 2 or 3 psig above the operating limit setting, but must
not exceed the safety valve setting.
4.
On a hot water boiler, the high limit temperature control should be 5º F to 10º F above the operating limit tem-
perature control setting but within the limits of the design pressure of the pressure vessel.
Inspect the modulating control for proper setting.
The control must be set and adjusted so that the modulating motor returns to low-fire position before the operat-
ing limit control opens. It is further desirable to have the modulating control’s low point setting somewhat below
the cut-in setting of the operating limit control so that the burner operates in low-fire position for a brief period on
each start rather than immediately driving to a high-fire position.
Inspect the low-water cutoff and pump control as well as the auxiliary low-water cutoff (if equipped with this
optional equipment). Check for freedom of float movement. Float movement can be verified by observing the level
of water in the gauge glass when the water supply has been cut off either by stopping the feed pump or by closing
the feed valve. Restarting the pump or opening the valve should result in feed water entry. If not, secure the boiler
immediately and determine the cause. The importance of proper functioning of low-water controls cannot be over-
emphasized. Be sure that the control and the piping are level.
The settings of controls relating to fuel, either oil or gas, are covered in subsequent sections.
NOTE: The settings of all the above controls may require some readjustment after the boiler is started and running
for a short period. The scale setting son the controls are relatively accurate, but are principally for use as guides. Final
adjustment should be based on and agree with the reading of the steam pressure gauge or the water temperature ther-
mometer.