An alternate method is to completely dry a clean
boil (by blowing hot dry air though the boiler) and
then purge the air from the boiler and pressurize
with 5 psig nitrogen. Be aware that all metal
surfaces which are not completely dry are
vulnerable to corrosion, particularly if oxygen is
present.
2. If a boiler has been down for repairs and is to
be laid up, it should be operated to pressurize with
steam and then drained and pressurized with
nitrogen as in step 1.
3. All connections must be blanked or tightly
closed.
Note: Operating boilers must be removed from
service to minimize adherence of boiler water
suspended solids on boiler metal surfaces. Refer
to previous instructions for boiler washdown.
RETURNING IDLE BOILER TO SERVICE
After wet lay-up
To start an idle boiler after wet lay-up, use the
following procedure:
1. If the boiler was pressurized with nitrogen,
disconnect the nitrogen supply source and vent
the boiler.
2. Using the blowdown valve, drain the boiler
partially and make up with feedwater so as to
dilute the chemical residuals to operating
concentration levels.
3. After the boiler water concentrations and the
water level are returned to proper operating
conditions, the boiler can be started in the normal
manner.
After Dry Lay-Up
To start an idle boiler after dry lay-up, use the
following procedure:
1. Disconnect the nitrogen supply source and vent
the boiler in a safe manner - external to the
building and away from air intakes. Then
thoroughly purge the boiler of nitrogen with dry air.
2. The boiler was to have been cleaned before the
lay up procedure. So it is necessary only to fill the
boiler with properly treated water. Then proceed
with start-up.
Summary of Contents for Forced Draft Steam Boilers
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