CHAPTER2
The suggested general procedure for cleaning a
boiler is:
(1) Refer to Fig. 2-4 to determine water
capacity.
Have
sufficient
cleaning
material
on
hand to complete the job.
(2) When dissolving chemicals, the
fol-
lowing procedure is suggested. Warm
water should be put into a suitable
con-
tainer. Slowly introduce the dry chemical
into the water stirring
it
all times until the
chemical
is
completely dissolved. Add
the chemical slowly and in small amounts
to
prevent excessive heat and turbulence.
(3)
An
over-flow pipe should be attached
to
one
of
the top boiler openings and
routed to a safe point
of
discharge. A
relief
or
safety valve tapping
is
usually
used. .
(4) Water relief valves and steam safety
valves must be removed before adding
the boil-out solution
so
that neither it nor
the
grease that
it
may carry
~ill
con-
taminate these valves. Use care in remov-
ing and re-installing valves.
Refer to Section
Min
Chapter 7 for valve instal-
lation instructions.
(5) All valves in the piping leading
to
or
from the system must
be
closed
to
prevent
the cleaning solution from getting into
the system.
(6) Fill the pressure vessel with clean
water until all tubes are covered. Add the
cleaning solution and then fill to the top.
The temperature
of
the water used
in
this
initial fill should be at ambient tempera-
ture.
750-150
THE
PRESSURE VESSEL
(7)
The
boiler should then be fired inter·
mittently at a low rate sufficient
to
hold
the solution
just
at the boiling point. Boil
the water for at least five hours.
Do not
produce
steam pressure.
(8) Allow a small amount
of
fresh water
to
enter the boiler to create a slight over-
flow that will
carry
off
surface impurities.
(9) Continue to boil and overflow until
the water
clears. Shut the burner down.
(10) Let the boiler cool to 120oF
or
less.
!WARNING
Be sure
to
drain the
hot
water
to
a safe
point
of
discharge
to
avoid
scalding
or
.
other
serious
per-
sonal
Injury
or
death.
(11) Remove the hand hole plates and
wash the waterside surfaces thoroughly
using a high pressure water stream.
(12) Inspect the waterside surfaces.
If
they are not clean, repeat the bailout.
(13)
After
closing
the
openings
and
reinstalling the safety
or
relief valves, fill
the boiler and fire until water
is
heated
to
at least 180°F to drive
off
any dissolved
gases that might otherwise corrode the
metal.
CHAPTER 2·9
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