CHAPTER4
SfARTING
AND OPERATING
INSTRUCfiONS
(1)
On
a high pressure steam boiler,
this
control should
be
set approximately
10
lbs.
above
the
operating limit pressure
control setting,
if feasible, or midway
between
the
operating limit pressure
and
safety valve setting. The setting on a low
pressure steam boiler
may
be
2 or 3 lbs.
above the operating limit setting, but
must
not
exceed
the
safety valve setting.
(2)
On
a hot water boiler,
the
high
limit
temperature control should
be
5-10•
above
the
operating limit temperature
control setting, but within the limits of
the
design pressure
of
the
pressure vessel.
Inspect
the
modulating control for proper setting.
This control
must
be set
and
adjusted so
that
the
modulating motor returns
to
low fire position
before
the
operating limit control opens.
It
is
further desirable to have
its
low point setting
somewhat below
the
cut-in setting of
the
limit
control so
that burner operates
in
low
fire
posi-
tion
for a brief period
on
each start rather than
immediately driving
to a high
fire
position.
NOTE: The settings
of
all
the
above con-
trols
may
require some readjust-
ment after
the
boiler
is
started
and
running
for
a short period.
The
scale settings
on
the controls
are
relatively accurate, but principal-
ly
are
for
use
as
guides. Final
adjustment should
be
based
on
and
agree with
the
reading of
the
steam pressure gauge or
the
water
temperature thermometer.
Inspect
the
low
water cut-off
and
pump control
as
well
as
the
auxiliary
low
water cut-off (if
equipped with
this
optional device). Normally,
no
adjustment
is
required since these controls
are
pre-set
by
the
original manufacturer. Check
for
freedom
of float movement. Float movement can
be
verified
by
observing
the
level of water
in
the
gauge glass when
the
water supply
has
been
cut
off either
by
lhe stopping of
the
feed
pump
or
by
750-150
the
closing of a valve,
and
the
restarting of
the
pump or opening
of
the
valve when water
is
drained
from
the pressure vessel. The importance
of proper functioning
of
low water controls can-
not
be
over-emphasized. Make sure that
the
con-
trol
and
the
piping
are
level.
The settings of controls relating
to
fuel,
either
oil
or
gas,
are covered
in
subsequent sections.
In
the
event
the
boiler
is
equipped
with
optional
control devices
not
listed here,
be
certain
to
as-
certain that their settings
are
correct. If additional
information if required,
see
your Cleaver-Brooks
local
representative or contact Cleaver-Brooks.
On
initial start-up or whenever
the
boiler
is
placed into operation
from
a "cold" start,
the
manual-automatic selector switch should
be
set
at
"manual"
and
the
manual flame control set
at
"close." After
the
boiler
is
in
operation
and
thoroughly warmed,
the
selector switch should
be
turned
to
"automatic,".so that
the
burner firing
rate
may
be
controlled
by
the
modulating control
in
accordance with
load
demands.
aose
all
power entrance switches (supplied
by
others).
C.
GAS
PILOT
The
gas
pilot should
be
checked
for
satisfactory
performance prior
to initial firing. Follow
the
pilot flame adjustment instructions given
in
Chapter
5.
On
initial starting attempts, several efforts might
be
required
to
accomplish bleeding
time
of pilot
line.
While checking
the
pilot adjustment, ob-
serve whether
the
pilot flame
is
extinguished
promptly when
the
burner switch
is
opened. A
lingering flame
is
indicative of a leaking
gas
pilot
valve
and
a condition requiring correction before
proceeding.
CHAPTER 4-3
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