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necessary, but the float control should be checked for proper operation. Make any
adjustments which may be required to maintain specified operating levels.
7.2.9 When a considerable volume of steam is issuing from the vent, throttle back the
vent valve until only a plume of vapor can be seen. The water temperature at this point
should rise to within three degrees of saturation temperature of the steam at the
observed deaerator operating pressure. A lower temperature would indicate insulating
pockets of air in the vessel. If this occurs, open the vent valve completely for a few
seconds to purge this air from the deaerator. Return the vent valve to its original
position.
7.2.10 Open steam valve fully.
7.2.11 When water temperature rises to within two degrees of steam temperature, the
system is ready for service. The pump suction valves may be opened and the vent valve
should be adjusted in accordance with Section 7. During operation, stored water
temperature should correspond to that of saturated steam at the deaerator operating
pressure.
7.2.12 Check all valves and float controls to be sure proper water level is maintained.
7.2.13 Some rumbling may occur with a cold tank. This should disappear as
temperature levels increase. Entrapped air is another possible source of rumbling; this
should be eliminated as described in 5.2.9. During operation, stored water temperature
should correspond to that of saturated steam at the deaerator operating pressure.
7.2.14 When proper operating temperature has been achieved, recheck all piping,
flange and manhole bolts, etc. for tightness.
7.3 Initial start-up, hot (steam available)
7.3.1 Open vent valve completely, exhausting to atmosphere.
7.3.2 Open steam valve slowly, gradually bring deaerator up to operating pressure. If
pressure – reducing valve hunts or pulsates, adjust until pressure remains steady.
7.3.3 Gradually admit water to deaerator by partially opening the gate valve in the
water inlet line. The rates of steam and water flow should be carefully controlled to
maintain a positive steam pressure in the vessel. This will be evidenced by a continuous
escape of steam through the vent. Water flow should be manually controlled until it
reaches a point sufficient for the water inlet float valve to maintain a proper level. At
this level, manual control will no longer be necessary, but the float control should be
checked for proper operation. Make any adjustments which may be required to
maintain specified operating levels.
7.3.4 At this stage, refer to Section 5.2.9, (in Initial start-up, cold.
7.4 Venting
Vent valve is furnished with an orifice in its gate. This orifice is sized for minimum
venting. Heavy concentrations of removed gases may require that the valve be opened
wider to permit their release to atmosphere. Water temperatures lower than that of
saturated steam at the deaerator operating pressure would indicate insufficient venting.
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