new boilers, expansion movement should be
checked to see that no binding or interference
When burning oil, prevent incomplete
combustion in the furnace: Unburned oil is
deposited on the cooler surfaces in the back of
the unit, such as the economizer and air heater,
and this creates a potentially dangerous
When the steam drum reaches about 25 psig,
close the vent valves on the boiler drum. Check
the steam pressure gauge now to be sure that it is
Ease up on the stem of the main steam stop valve
to prevent any serious expansion stresses. If
there is no steam on either side of the main steam
stop valve, gently lift and reseat it to make sure
that it is not stuck. Open the drain valve on the
boiler side of the main stop valve.
Observe the water level carefully to ensure that
no water is carried over into the superheater.
Maintain a normal water level in the drum by
blowing down or feeding water as may be
Operate the vent and drain valves in the
superheater headers and economizer by
following the manufacturers instructions. In
general, drain valves in the superheater inlet
header are closed first, followed by the drains in
the superheater outlet header. In any case, the
superheater outlet header drain and vent valves
must not be completely closed until enough
steam flow through the boiler outlet valve is
Check for leaking gasket joints. If a leaking
gasket is discovered, shut down the boiler and
tighten the joints.
If the gasket still leaks, drop the pressure again,
replace the gasket, and repeat the lighting off
Before cutting in the boiler, proceed as follows:
1. Open all drain valves between the boiler and the
header, especially the drains between the boiler
and the two stop valves.
2. Warm up the steam line between the boiler and
the header by backfeed through the drip line or
by means of the bypass valve.
When the steam line is thoroughly heated and at
header pressure, open the bypass valve.
When the boiler pressure almost reaches line
pressure, open the bypass line around the main
steam stop valve to equalize pressures and
temperatures in the piping; then slowly open the
main steam stop valve. As the boiler reaches line
pressure and is actually steaming, slowly raise
the nonreturn valve stem to the full open
After the boiler is on line, close all superheater
Inspect the entire boiler, and close any drain
valves that are not discharging condensate.
Close the economizer-recirculating valve when
an adequate continuous feedwater flow is
Close the drain valve at the nonreturn valve.
Close the bypass valve around the nonreturn
A boiler with a pendant (nondrainable)
superheater has a slightly different operation.
Superheaters of this type trap condensate in the
loops that must be boiled off before the firing
rate can be increased and the steam flow started.
Maintain a constant firing rate. The strength of
thick steam drums may be impaired by
excessive temperature differentials between the
top and the bottom of the drum, if the proper
firing rate is not maintained. Tubes may start
leaking at rolled seats and the superheater tubes
On boilers generating saturated steam, follow
the above instructions for removing air and
Success in operating boilers depends largely upon
the operators performance. No fixed set of rules can be
established to fit all conditions. Consequently, the
operator must see and interpret all prevailing operating
conditions and, if necessary, take action to control,
modify, or correct them. To be able to do this, the
operator must be thoroughly familiar with the
characteristics and standard operating procedures for
the boiler for which the operator is responsible. This
section acquaints you with some of the basic operating
procedures that generally apply to most, if not all,