supplied with fuel. It is kept at a value that has
Information of importance in the operation
of boilers must be recorded. This section provides
information concerning the type of data that
should be recorded in logs.
1. Steam pressures. Steam pressure is re-
corded by the operator from steam gauges and
shows performance of automatic or manual
2. Steam flow. Actual output of the plant
is recorded by the operator in pounds per
hour to obtain steam flow. This record determines
the number of boilers to operate for greatest
3. Feedwater heater. Feedwater-heater pres-
sure indicates whether proper deaerating
temperature can be maintained in the heater.
Feedwater-heater temperature shows the effec-
tiveness of the feedwater heater. A drop in steam
supply pressure or insufficient venting may cause
low heater temperature.
4. Feed-pump pressure. Feed-pump pressure
indicates effectiveness of the boiler feed pumps.
If feedwater supply fails, the pressure reading
enables the operator to determine whether or not
the difficulty is in the feed pumps. The pumps
are defective when the feed-pump pressure reading
is below normal.
5. Forced draft. Forced draft is an indication
of thickness of the fuel bed. The most satisfac-
tory value varies with different installations and
fuels and is determined by actual trial.
6. Furnace draft. Furnace draft, when used
in connection with forced draft, should be slightly
less than atmospheric pressure to prevent smoke
from leaking into the boiler room and overheating
the furnace lining. If only an induced or natural
draft is used, furnace draft must be sufficient to
cause the quantity of air required for combustion
to flow into the furnace. Operating with a
furnace draft higher than actually required results
in excessive air leakage into the setting with an
accompanying loss in efficiency.
7. Last-pass draft. Last-pass draft shows
actual draft produced by a stack or an induced-
draft fan. Fireman should become familiar with
last-pass draft at various ratings when the boiler
is operating satisfactorily. A decrease in last-pass
draft with- other conditions constant indicates
leaking baffles. An increase in last-pass draft
shows that gas passes are becoming clogged.
8. Percent CO2 flue gas. Percent CO2 flue
gas is a measure of relative quantities of air
been established as most satisfactory for the plant,
fuel, rating, and like factors. In plants not equip-
ped with CO2 recording meters, this value is deter-
mined with a hand gas analyzer. With experience,
you can determine the correct amount of air sup-
plied for a furnace by checking the draft gauges
and from personal observation. In all cases, you
should check values by use of a hand gas analyzer.
9. Flue-gas temperature. Flue-gas tempera-
ture is an indication of the portion of heat leav-
ing the boiler with the flue gases. This heat
represents a direct energy loss in fuel. Abnormally
high flue-gas temperatures at a given boiler rating
are caused by dirty heating surfaces or leakage
of baffles. If the heating surface has a coating of
soot and ash, heat that cannot escape is discharged
to the stack. Leakage through baffles allows the
gases to take a shorter path than intended and
reduces contact of gases with the entire heating
surface. Excessive fouling of the boilers firesides
increases the draft loss while leaking baffles
decreases the draft loss. Either condition raises
the temperature of flue gases above normal.
10. Fuel. Always determine the quality of
fuel being used as this represents a major
a. Pounds of coal. Procedures for deter-
mining the quantity of coal burned depends upon
the means available. You may use scales that auto-
matically dump weighed quantities of coal into the
stoker or pulverizer hoppers. A register indicates
the number of dumps that, multiplied by the
weight of coal discharged per dump, gives the
total. Another weighing method uses traveling
larries equipped with scales so that the weight of
each load can be recorded before it is dumped into
the boiler hopper. In the absence of a weighing
device, the quantity of coal consumed can be
determined by filling and leveling bunkers at given
intervals and recording the coal used from the
report of coal received during a given interval.
Methods for approximating coal burned by count-
ing stoker revolutions are only estimates and are
subject to considerable error when the size of coal
b. Cubic feet of gas. The quantity of gas
used is indicated on a meter. The readings can be
direct or they may necessitate calculation by use
of a meter factor.
c. Gallons of oil. Fuel oil quantities are
determined by use of a measuring stick. Tables
supplied with a given tank are then used to deter-
mine quantity from level of fuel. Tanks may also
be supplied with gauges that can be read directly.