Universal Boiler Works | BF100W4 | Specifications | Universal Boiler Works BF100W4 Specifications

Operating and
Maintenance Manual
Water; ASME Section 4
Ship Date: 1/24/2000
T: (309)932-3088 F: (309)932-2078
ubwl@inw.net www.universalboiler.com
1207 S.E. Second St.
Tel: (309) 932-3088
Fax: (309) 932-2078
, ! W l E R SERIAL #:
A. The Boiler
The Universal Boiler Works, Inc, (UBW) Model
BF, is a 5 pass steel wa&tube boiler of the "0"
type design. It consists of the upper and lower
headers with interconnecting downcomer and
flexible tangent tubes, The tubes are
symmetrically installed to provide uniform gas
side and water side fluid flow.
A11 boiler tubes are a minimum of 1.5 inches:
meter, 0,095" wall through 700 horsepower
kid 2 indiameter 0.105" wall for units
above 700 horsepower. Each tube is fitted with
a f e d at each end, which is press fitbed into
each drum hole.
This method of tube
attachment permits easy replamment of tubes
without the need for welding or d i n g . (See
Figure 1-1)
Multi-bend tangentially mmgd watertubes
form the combustion chamber (furnace) and
convection gas passes.
Specific tube
arrangements and the front and rear walls
provide the means for gas flow direction
without the use of baffles. (See Figure 1-2)
In accordance with the ASME (American
Society of Mechanical Engineers) Code, the
boiler is designed, fabricated, tested, and
inspcted following the mtes of Section W for
(operating at less than 2500 F.)
I Power Boil= (operation at greater
'irran 2500 F. or above 1 60 psig), and stamped
accordingly. The location of the authorized "H"
or "S" stamp is located on the upper header near
the rear ofthe unit.
As a complete package, the pressure vesse1 is
mounted on a 4" high insdated base frame.
This base frame includes the lifting Iugs for
rigging purposes. Over 200 horsepower, the
base is 6").
A series of 11 gauge steel panels, which are
bolted md sealed, provide a gas tight inner
casing of up to 3" W.C. Attached to this inner
casing is a 2.0 inch thick fikrgiass insulation
blanket rated at 2,3000 F.
The outer casing is fabricated of 14 gauge
corrugated aluminized steel panels, underlayed
with 1P2" thick fiberglass blanket insulation. A
2 inch air space between the inner and outer
jackets provides additional cooling of the outer
surfaces of the boiler. (See Figure 1-3 and
Figure 1 4 )
The combustion chamber floor is insulated with
ceramic fiberboard rated at 2,000O F and the
front and rear walls are poured refractory rated
at 2,8000 F, For Section 1 Boilers, the lower
drum is insulated with a 2,3000 F fiberglass
Universal Boiler Works. tnc,
Chptcr I General Description o f Hat Water Boiler
Please refer to Figure 1-5 for a visual
o f the parts and connection points
that cornprlst the boiler. This will help in
understanding your unit before start-up and for
any questions that may arise, for which you
require answers.
Refer to the G e n d
Arrangement drawing fur specific connections
sizes and location dimensions. The General
Arrangement drawing will also depict optional
items that were added in accordance with the
project specifications.
C. Pressure Parts
The BF hot watcr baiIer has two (2) dmm or
headers, one uppw and onc Iowtr. The upper
dnun is supported by the rear down~~mcr,
and rear walls, and steel structm. Tappings for
the water temperature sensing controls arc
Iocated at the front of the upper drum including
the tapping for the primary low water cutoff
control. At the rear of the upper dnun are the
tappings for the safety relief valves. The
conn&on of the bailer water supply to the
system is located at the kont of the upper dnun.
On the top centerline of the upper drum at the
front, is the vent connection. This should be
piped to the expansion tank.
The lower h,sometime r e f d to as the
mud drum contains the drain connection,
located at the rear bottom ctnbrlhe. A drain
valve should be instalIed to this connection by
the installing contractor a d piped to a safe
discharge point. -hD8~h&
NOTE: The Model BF hot water boiler does
not include tappings for fresh water make-up,
Treated water make-up when needed, should be
added via the expansion tank, A tight hot water
system should have a minimal amount of makeup and a water meter is recommended to
monitor the amount of water make-up.
The term wn~rr~ri
covers the olectr icnl or electro.
mechanical devices mounted on the boiler or
furnished loose For field installation. The*
devices work in harmony with the burner
operatinghaintenance manual. Turn refers to
mechanical items such as valves, pressure or
temperature indicating devices, and piped items
responding to the boiler's pressure or
temperature functions.
Regardless of the
component, the authorized boiler operator must
b h i l i a r with all mounted and if furnishad,
*mote mounted items that will affect the
cpmtioa ofthe boiler.
Spceific controls fitrnishod for the project will
be denoted on the General hangement
drawing and on the Bill of Materids list.
refer to Figure 1-5 for cmfrol Iocations.
- This
starts and stops the bmer based on the
sy&m h a n d for d i t i o d heat or
when the demand is satisfied,
. . CQnfml
2. Wieh_Lmlt
This device,
ats0 h o w n as an Excess Temperature
Control, stops the burner when the
normal operating temperature set-point
has been exceeded. Normally the device
is a mechanical manual reset type,
but may be wired to affect a manual
reset via the combustion flame safeguard
control .
3, k h h h u g C
For burners
which oprate on the full modulation
principle, this device positions the
burner from low fire to high fire in
response to system demand. When a
Universal Boiler Works, Inc,
full load is required, this control will
signal the burner to drive to the
maximum firing position and as the
load is satisfied, positions the burner to
less input, eventually driving the burner
to low fire for safe shutdown upon
demand ~tisfhction. Smaller units, 1than 80 horsepow, wilt b standidy
equippod with a control that positions
the burner either at full fire or low fire
and is referred to or hown as a
ow Fire Canb.al. While it is
design4 to respond to the system
demand, it is not designed to position
the bunttr at any pint in betwen high
or low firt.
A probe sensing
safe operating level. In a
device below a
hot water boiler, this device should be a
back up to a system water sensing
device, as a low W r level in a hot
water boiler is very serious and will
affect the longevity of tbe tubs.
b i l e r Trim
I . W e r Water Pressure Gwgg Mechanical indicating device for visual
indication of the internal pressure of the
boiler (waterside).
Mechanical device to indicate the
relative water temperature at the outlet
connection to the system,
3. Brlief Valve(s\
Dependiny upon the
s i x of the boiler. one or more water
pressure relief valves are furnished.
These valves are shipped loose and
should be piped to a safe point ofdischarge by the installing contractor. The
set point is genera1ly iess than the system
operating pressure, to relieve water p n t i
sure within the bailer when the set
point has been exceeded. Under no circumstances should the setpoint be
altered above the system design nor
above the boiler design pressure. Vdve
sizing and quantity are determined
accordance with the
Additional valves
be added in accordance with the
project specifications.
(Optional) When fumishd, this 6
vice is shipped l ~ o s efor instaktion by
the contractor. This device indicates the
outlet gas temperature of the boiler. It
is normatly laxted in the vertid rise of
the stack to the boiler connection;
approximateIy three feet above the
boiler connection. Provides indication o f
the fireside cleanliness of the boiler.
w W-CuW(Optional)
This device, when required by pject specifications, can be of the inprobe sensing type or an exkmd float
actuated device. Its purpose is to shut
the burner
should the primary low
water cutoff fail.
5, m
1 General Description o f Hot Water Boiler
(Optional) When finished, this valve
is shipped loose for contractor piping
( rear drum connection) and is used
to drain the boiler for waterside inspection or when the unit is to be stored, for
any lengthy period.
6. J n w W a t d 2 m h i u - (Optional)
When an optional float actuated
control is furnished in lieu of the
standard prok control, a drain valve
is furnished. This valve is factory piped
to the bottom of the float housing to
Universal Boil e t Works. Inc.
C h a w I General Oescription of Hot Water Boiler
permit periodic draining of the hwsing
to remove any accumulated sludge.
Locared on the
burncr. provides purge air of the bile<
prior to ignition and following a safe
shutdown. Provides the air required for
E, Burner Controb
The Model BF boiler is design4 Fbt operation
with a forced draft b m e r for natural gas, LP
gas, or light oil. A separate burner mmmt fram
the specific burner manufacturer is included. In
that manual are the descriptions of the various
controls provided in a c c o ~with the
requirmenl of the Undetwfitds IAmratory
W.L) and any specific requirements of the
project, in a c c o ~with the project
specifications. Within the bucner manual, one
will find the Burner hhmgment Combwtiun
Safeguard Conml along with Sm-up
instructions and combustion settings.
For fuel supply connections, refer to the &nerd
hangement drawing and the burner manual.
Folced - Located in the
Control Pmel. This device al1ows
current flow to the fan motor upon
energization of the coil. Overloads are
within the starter to prevent
damage to the motor in the event of
voltage or current spikes.
* .
- For W-
latiom opcnting on a 3 phase powcr
supply, this device is located in the
controI panel for stepdown.voltage of
120 volt single phase supply to the
b w e r and boiler controls.
Located on the burner
position the fuel input valve ad the i-'E
d e t air damper in accordance with
demand requirements.
As a brief aver-view, the package wiI1 contain:
-L '
1. Cantrol-hcatedootkebmeron
smaller units or on the boiler b
extension at the front of the boiler. The
electrical supply for the burner and
contsoIs are to tre made in this panel,
interface connections to system
contmls or shipped loose controls will
h y
7. Gas TTraia Standardly located on
the left side of the bailer, when Each
front of ?heunit. The train for
units operating on gas, as a minimum,
will have a main gas pressure regulator,
shutoff cocks, safety shutdown
be lmted within this panel.
valves, and fuel input valve. Please refer
to the burner manual for specific gas
train components.
Located in the Control Panel to provide
safe start procedure for burner start-up,
burner operation, and safety shutdown.
Flame supervision is via a flame scanner which monitots pilot ignition, main
flame ignition, and flame strength
during operation, It is programmed to
shut the burner fuel supply off in the
event of an unsafe condition.
? - A separate pilot regulator
and pilot safeg shutoff valvc are
h i s h e d on the bmer for gas pilot:
NOTE: Some units operating on oil may
be equipped with direct spark ignition.
Universal Boiler Works, Ine.
m I Omed -ription
and as a minimum will include oil
metering valve, oil pressure regulator.
oil strainer, safety shutoff valves, and oil
pressure gauges. Standard atomization
of oil is via mechanical pssurization.
Air atomization is optional. Pleast refer
to the burner manual for spific oil
components furnished.
F. Other Controis
Specific project requirements may have
included controls not mentioned in this Ocneral
Description section. These items csln include
Ieadflag systems, indoor/outdoor
management interface systems, system pump
interlock, etc. For specific items furnished by
UBW, refer to the Bill of Materials and the
Burner Manual for additional infomation.
2* is important to unthe operation of
device, which will hterhcc with the
boilerhumer, so that all components oprstc as
they have been selected and designed. Do not
attempt to by-pass any control or device during
start-up or during operation in order to e x p l i t e
start-up or continue operation. Each device on
the package has been firmished for a specific
reason of d e t y or infodonal purposes. If a
component is not operatiod, coatact your I
service agency or UBW.
of Hot Water Boiler
Chapter 2
Unloading and Installation
Model BF Hot Water Boiler
A. Unloading
Before any attempt to unload the boiler
from the transport company is made,
perform a visual inspection of the boiler.
Ascertain if any damage has been
incurred during transit. The equipment
has been loaded by UBW and accepted
by the transport company as undamaged.
Once the equipment has been lifted h m
the trailer, my damage that is not filed
against the Transport Company, will be
the responsibility of the rigger or
boiler base frame. (Please refer to figure
2- I ) These lugs have been located for
the specific purpose of lifting the unit
with the use of a spreader bar. A
spreader is needed to prevent damage to
the outside casing.
Refer to figure 2-2 for the correct
placement of the spreader bar and
Smaller units, depending upon the
available equipment, may be unloaded
via a forklift. If a forklift is used,
ascertain its lifiing capabilities and the
use of extended forks.
the boiler will mt be zm~aiiedfor
m e perid of time qfter ddivery, #he
mit sbuId be protected adequately
again#fallen debris, the weather, etc.
extended storage will be neceswty,
proper @-up uf the unit s h d be
provided to prevent o w n piof the
tubes. Make certain thst all s
loose or separate& boxed componenb
ar~dconirob me stored with rite Boiler
or proper& marked arad located, so that
whet1 the items me reyiired they can
easily be reaimed Check that all items
have beet1 received. Report tzry missing
items. Ifems not noted us missing, within
48 kvrrrs of receipt, will twt be replaced
of charge, as we will mmme thai
/he shipment h beet^ received
The Model BF boiler is equipped with
lifting lugs located on each side of the
X)o not attach slings around the b o i k
or to the burner in an attempt to p d
or drag the unit!
If the unit must be dragged or pulled,
attach cables to the lifting lugs only.
UBW does not recommend &aaaraaarnp
unit for awv wed Gisfmre, If the unit
must be placed into a location other than
lifting into place, we recommend the use
of rollers.
t:rlrrcrs;~lIJullcr Works. Ir~c.-. L'11;bpcr 1 UntuJiny 2k l~~slallrrtwn
ol' kldol 131: 1 lot Wa1c.r t3oilcr
The Mode! BF boiler must be installed
on a level surface. Ir i s recommended
that the unit be placed on a
housekeeping pad to prevent water
splashing during routine floor cleaning.
As a rule of thumb. we recommend that
a quantity o f 10 ctin per boiler
horsepower airflow be available,
whcncver the burner is operating. The
location of bailer room air supply
dampers should provide cross flaw
ventilation. The recommended size of
the openings shouId be i n accordance
with TabIe 2- I .
Model BF boiler is
adequately insulated and has an enciosed
combustion chamber, do not instal1 t i e
boiler on a combustible surface!
Ascertain what the local code
requirement dictates and as well, the
project specifications, for the type of
surface upon which the boiler is to
Make-up air openings may be fixed or
may include a motorized drive for
opedclose operation. Tf the openings are
furnished with an electrical drive, check
the burner electrical wiring diagram ibr
interface connections. The burner must
be started if the air dampers are closed.
Tf the unit is to be installed on a trailer,
piece of equipment, make
certain that the trailer floor is adequately
insulated if the floor is wood. We
recommend that the .floor be covered
with sheet steel or some type of heat
adequate service and maintenance space
is provided. As a minimum, a 30-inch
Although the
as a portable
resistant covering.
Project specification will dictate the
location and orientation of the boiler
within the boiler room. The boiler
should be located in a well-lighted area
and boiler room air supply ducts should
not be positioned near the rear of the
boiler. Cold air hitting directly on the
unit can have an adverse eff'ect on the
D.Air S u ~ ~ i v
Adequate air supply into the boiier room
combustion must be provided.
Ij'ndcr no circumsiancc should the boiler
be operated when a negative pressure
{~acuurn) cxists. We recommend a
siiyntiy positive condition at all times.
space should be allowed at the rear of
the boiler, a minimum of 30-inches at
rhe front of the boiler for burner
sewicing and for each side. Refer to the
General Arrangement drawing far aisle
specifications may require more room.
(See Figure 2-3)
NOTE: Project specifications andlor
local codes may require more service
clearance space than noted above.
To ensure rase uf access to the t itbes,
11ot it~stnlithe unit against a wall or
other su~nortingstructures. This wili
prevent access panel removal. The outer
and inner casings are removable to
provide access lo the tubes from each
sidc of thc boilur. Therc is an access
cioor at the back of the boiler for access
to ~ h ccombustion chambcr, Kecp this in
mind when placing piping, etc. at the
back ofthc unit and alony thc sidcs.
gnd lcakaee of combustible
As an option. access panels located at
the rear of the unit f i r cleaning and
inspecting the convection passes, may
The stack outlet should be fitted with
some means of preventing ingress of rain
as shown in Figure 2-4.
have been M s h e d . Check the general
arrangement drawing if these have been
furnished to ascertain if clearance at the
rear will be adequate for tube surface
F. Connections
Local cdes and project specifications
wilt dictate the requirements for all
interface connections of fuel watts
requirements must be adhered to and
inspected by the authority having
jurisdiction for the installation. UBW is
only noting the location of the
connections fbr reference, along with
other recommendations not con£lichg
with code or specification requirkmmts.
Wfer to the g
d arrangement
drawing for connection locations, sizes
and types.)
or Breacbinq - This
connection is located on the top
centerline of the boiler at the rear.
The specific size and dimensioned
location are noted on the General
Arrangement drawing. If a vertical
stack is furnished, do not allow the
boiler to be the support for the stack.
The stack should be supported 60m
the roof trusses or another means of
stack support should be provided.
1. Stack
Do not permit the stack to slide
pl~stthe boiIer connection so
that it rests on the umer drum.
This will create n backaressure
a ~ i dseriously affect co tn bus don
2. U ~ g l ~ I R e t u r- nThe hot
water supply connection to the
system is located on the upper drum
at the front, and the system return
comction is located at the rear of
the lower drum. For multi~ieboiler
mshlhtions, it is recommended that
balancing valves be i n d i e d in the
return line, to 9insure equal flow to
each boiler, ai the required flow rate.
(See Table 2-2)
- To ensure that entrained
air is not ailowed to accumulate, aa
air vent tapping is located on the top
drum centerline at the front. This
connection should be piped to the
expansion tank San auto air vent
valve can be used, but is not
recommended in Iieu of expansion
tank piping.
3. Air Vent
4. Boiler Drain - For draining the
boiler, a tapping is locatmi on the
bottom drum wntdhe at the rear.
Connect an approved vdve to this
opening and pipe to a safe and
approved discharse point.
NOTE: For Section I hiyh pressure
boilers or as Iocal codes or
specifications may dictate, one quick
opening and one slow opening valve
shall be installed to the boaom drum
drain connection. The valve closest
to the drum shall be the quick open
type, directly into the boiler. For
nlost effecfiveness, we recommend
that the chemicals be introduced into
Unnvrsal h l c r Works. Inc,
the fucd
Chilpicr 2
- Uni-ng
R insr;l~k~Il~ll
ol' kldcl B1: I.Ioc Water Uoilcr
diamctcr larsur h r tach 12
prior tu boi1cr
feet length.
5 . Relief Valvds) - Thest. items are
shipped separate and must be
inounted direct to the boiler withuut
any interveniny shutoff devices. The
Avoid all
connections are located in the rear
top dnrm. Discharge piping shdI
foIlow local code requirements.
outdoors wherc it can be
subjected to freezing, ensure
appropri atc measures prevent
the discharze pipe from
fr'reezing shut.
Improper handling or instabtion of a
relief valve may adverseIy affect the
valve's operatian, multing in serious
damage to property and life.
i Each discharge pipe should
have 36"
Or X" Open drain at
its lowest point.
Observe the following precautions when
installing relief valves.
Refk to Figure 2-5 for a recommeraded
method of safety valve dischaqe piping.
P Use only flat jawed wrenches
6 . Electrical - Foliow lucal c d t v and
the National Electric Code w C ) for
an the flats of the valve.
Do not use
a pipe threaded
into the outlet wnnectiorl of
the valve to turn the valve.
"r Avoid over tightening, which
can distort the valve's seating
only a moderate
amount of pipe compomd to
mate threads only.
9 l3ischrrrse pipins rn~~stbe
used if the discharge is
iocated where workers might
be scalded.
3 Ciscl~argepipe dian~eteri i 1 ~ 5 t
be at least equal EO the size of
the safety valve.
> If' discharge pipiiig extends
greater than 17 feet, use a VZ"
cmnection of the mh power supply
connectmns. Power connection
points are provided in the burner
control pami. M e r to the burnerwiring diagram for details.
7, Gas Fuel - If the burner is equipped
to burn gas? the gas trz?in is located
on the left side of the boiler when
facing the burner. (Note: project
specifications may locate the train on
the opposite side, or i~ may have
been shipped not mounted for a
specific ~ocation).Locd codes wiil
govern the supply line connection to
the bdler hit s h d d inchide a drip
and strainer prior to the
connection a~the boiler. Refer to the
hcrner Sas tmir. dzwing fgr vent ! i ~ e
dctai4 of the individual, componcnts.
(NOTE: Do not run the supply line
tli~shtn the side nf the boiler, which
will hamper casins removal)
8. Oil Fucl - Rcfcr. to the burner
manual tbr specific controls and
componellis. It' an integral oil pump
is furnished, this will be Iocated ,at
the burner to which the suction and
return lines are to be connected. If a
remote pump is furnished, project
specifications will note the location
and piping.
local s~ecificat
gpverning code middines for f d
G. Water Treatment
The following layout, marked Hot
Water Generator Room Plan shows
two hat water boilers feeding two
heat i vg zones.
A stand-by pump is shown to pump
either of the two zones. This is possiile
only if the water flow and pipe Friction is
practically the same for each zone.
The expansion tanks are shown
connected to the top of the low water
cutoff (if a float operated control is used,
otherwise connect to the vent connection
on the upper drum) to prevent air
binding in the control or drum. The cold
water make-up line is connected to the
expansion tank header, and make-up
should be treated and softened.
An isometric view is given to show the
piping for Rot water operation in the
180' to 7-40" F ranges. The system
shown describes the popular pump-out
system, with the pumps installed on the
hot water line leaving the boilers. This
system offers the advantages of constant
water pressure in the boilers with the
espansion tank connected to the boilers.
Also, on high friction head systems. the
pump discharge is not imposcd an the
bailers and standard Section IV boiler
units can be used, provided extreme
static head pressure does not exist.
The return water enters the bottom rear
drum of each unit and the hot water
supply take-off is from the top front
drum. The run-out should include an
elbow that moves the shut-off valves off
the boiler centerline. allowing the valves
to be accessed without climbing onto the
A balance cock is shown for each boiler
and must be utilized. It is impossible to
perfectly balance the flow of water
through each boiler simply by piping
design or via the use of gate valves.
Unequal flow will impact the proper
response and load demand on each
Zone threeway valves should be
designed for proper pressure drop to
prevent huntins and they should be of
the slow open md slow close type.
Never allow the vaIves to fully close so
that the flow m y be established t h u g h
each boiler. Should the heating demand
not require the use of more than one unit
for my lengthy period, it is
recommended that the boilers not used
be properly valved out. System pumps
should be interlocked with the burners to
prevent burner operation unless the
pump(s) is operating.
Pressure vesset warranty is subject to
proper water treatment. 1f wwtcr
treatment is not undertaken, pressure
vessel wilrrantv i s voided.
I.:i~ncrwlBoikr Wurka. Inc.
- C'hapcr 2
Unlouding dk l~~sltlllario~~
ol' Mudcl 13F Hot W;llcr b t l c r
h i l e r should be ample sire and not less
Ooequaner inch copper
piping. that is seen often in boiler
installations should be avoided. as it is
easy to plug up such small vent piping,
leading to an unsafe operation of the gas
accessories. 'I'he gas vents shouid be
tminated outside of the building wall
and be equipped with a bug screen type
venl cap. As shown in Figure _C, vents
htom test cocks or vent valves should not
k combined with vents from as
pressre reglators.
safety of a gas-tired boiler
instd!ation is cantrolled 'by the care
taken in the application of gas
accessories to the combustion equipment
on the hoiler. Fi,m_lres A. B and C
describe some of the various
appiications of gas se~.vicesas weii as
some of the details that should be taken
care of, to ensure that a saik and efficient
installation is secured.
Figure A shows an incorrect methad of
connecting gas service to a boiIer. As
show, it is impossible to ch9cl; the piiot
on the boiler without
electrical head to the main gas valve. It
is not recommended that the pilot line be
down-stream fmm the main manual
shut-off vatve,
F i ~ u r e3 shows the correct method of
connection of the pilot line to the main
gzs Fine. With this hook-up, it is possible
to shut-off the main gas valve and run
the burner on pilot only, so that an
eficient, stable flame can be secured by
proper adjustment, After the pilot is
properly adjusted, the operator or server
technician can then open the main gas
vatve and be assured that the boiler will
I:.llshr properiy. Szlme gas cozpanies may
I-eyuire ail additional g u valve ahead of
the pilot connection.
it is exrremcly important that vent piping
from sas regulators. solenoid vent valves
fir check ~ r behinstalied correctly to
prevent the escape of gas into the boiler
room, in the: event oi improper operation
or by failure of a _pas regulator
diaphragm. The gas vents from the
As shown in aH three figures, it is
preferable to run the gas drop (drip or
dirt leg) itII the way to the floor, thus
providing support of the gas piping as
we11 as a dirt pocket, to catch welding
spatter or scale, before it enters into the
gas train components. (@Tote: keep rhe
gas drops behind and away from the side
of boiler to permit removal of side
casing and tube pull from the Sailer)
Keep the gas drop behiad and away kern
the side ofthe boiler to permit removal
of side casing and tube pull from the
The manual shut-off valve should be of
the lubricated plug type or baII type, nd
a cone type brass cock. A Iubricatd plug
valve will not freeze and become
biEcilt to ttiri;. This ~ a l v cshculd be
equipped with a per-nmlelltly attached
handle that indicated whether the valve
is opened or closed.
The requirements of local gas utilities,
and figtima! x d e s shou!d be
checked carehlly, S e f m making .the
ti.nai connections ul' the gas service to
the boiler. As a minimum. the gas train
Ilt11icml f3wlcr Works. lac.
Ctwplcr L
Unloadmy & Irisultation ol' Mo&l UF Hot Wil~ctBvilcr
components should be in accordance
with L ~ laicst
111. standards li)r gas l i r d
I. I,iel~tOil Circulating Purrlp
necessary to locate the loop over the
boilers, a check should bc made to insure
that the pumps on the boilers cortld with
stand the suctiurl pressure imposed by
the height of the loop,
Oil pipiny
different types of burners and the
specific burner manufacturers' data
should be consulted. to determine
specific pumping requirements Burners
that operate with mechanical pressure
atomization of oil for combustion must
be known, so that line size is proper fbr
adequate oil supply at high fire.
requirements vary
Mechanical oil atomization generally
utilizes the burner pump to increase the
oil pressure at the oil nozzle, for proper
atomization. Consequently, the oil flow
to the suction side of the pump must be
at least twice the fir in^ rate capacitv
at hiph fire.
The illustration shows the installation of
a light oil transfer pump for a multiple
boiler installation. The drawing depicts
the preferred method over pressurized
supply lines or s d l storage tsnks in the
boiler rmm.
The suction tine between the tank and
the circulating pump should be tested for
24 hours under 100-psig-air pmure; to
insure that it is tight before it is covered.
One oil pump is shown as only one
piimp is usually installed, if oil is a
stand-by fuel. If oil is the primary fuel,
tw*o pumps should be installed in
parallel. If two pumps ate used or if gate
valves are installed in the discharge line,
the pumps should be equipped with
safety relief valves.
The uil loop rovrtl the pump to the
boilers and hack to the tank should be
located in a trench, if possibte I F it is
Per NFPA standards, the pressure
imposed on the suction side of the
boiter-mounted pump may not exceed 3
Therefore, a pressure-reducing vaive
may be required.
By raising
the end of the Imp up one
foot, a positive supply of oil is available
at all times on the suctions of the pumps
at the boilers. If the oil bop is located in
a trench, the end of the loop should be
raised at least one foot above the
elevation of the pumps on the boilers.
This system has a number of advantages
over pressured supply lines or d
storage tanks. These are:
I . Minimum of pressure required in the
oil supply line.
2. Minimum amount of oil storage is
required in the boiler room.
floats switches, pressure
rewlators or relief valves required,
other than noted above.
4. Oil cannot spill out of vents or
ove:tlows that are required on other
J. Electrical
Power Supply to the boiler must be
protected with dual element fbses or
breakers Similar fhes should be
used in branch circuits. Standard oneshot t i ~ s e sare not recommended.
tfnlrrml &~rlcrWorks, Inc.
- Chaplet
1 -Unloading& Irmlldon of M&l BP HOIW u w BoiLr
foR>rmtion in Table 2 4 is inuiudcd as r
widel ine of fuse protection requirements
and thcsc shouici bc confirmed with
project speci Acacions. burner provided.
and shouid bc in accordancc with the
latest NEC (National Electric Code)
requirements and local governing codes.
It is recommended that Emergency
Power Disconnect switches be located at
each entry ~ n t othe boibr room. These
switches should be interlacked with the
boilerburner control circuit.
hfakc sure that all external wiring to stnd
from the control p e l is properly
identified and marked. This is to ensue
that if burner power is disconnected,
oiher power sources are known and
marked, which may remain active within
the panel, even fhough the burner power
has been disconnected.
Check that the wiring diagrams for the
burner and boiler controls are contained
in tam w n h l panei print pocket at dl
times. Reference thae drawings for
external cunnections that rnsy require
inledace wiring with other controls. If
these drawings am not nvaiiable, check
with your local UB W Representative.
Chapter 3
Model BF Boiler
initial Start-Up m d Operation - Hot Water
A. General Preparation for
Before initial burner fwhg is undertaken,
be certain that dl conndons have been
completed and secured. Make certain
that the vent, water, firel, elemid
services are complete and that
interruptions will not occur during the
start-up procedure.
J Motors
connected fbr
4 Fuel-supply
and fUel
J Exhaust ventlbreeching connected
and h e of obstructions?
J Combustion Air Make-up available?
J hterfkce
wiring completed to
external controls or devices?
J Water supply piped?
J Drain and Relief Valves piped?
J Inspection cumple4ed?
J Sufficient Load demands available
for setting combustion and controls?
During fabrication of the boiler, heating
surfaces are subjected to cutting oils,
grease, etc. These must be removed
prior to full operation of the boiler. To
accomplish this, a boil-out of the unit is
recommended. This procedure can be
M e d out dong with the cleaning the
system, and can be accomplished during
the time period to cure the fiont and rear
wall rehctories.
The & system should be cleaned
including the boiler, befbre full
operation of the boiler is p e n m d .
Piping connected to the boiler may
contain oil, grease, or other materials
detrimental to pumps and the boiler.
These irnpwitieq if not removed, will
adversely affect the h d n g d c e s of
the boiler. Chemical cleaning of the
system piping is necessary and the entire
system drained after cleaning. If the
boiler is replacing an existing unit within
m existing system, boil-out of the
system modifications, impurities may be
introduced and it is recommended that
an existing system be reviewed for
C. Refractow Curing
The front and rear walls for the BF unit
are constructed of high temperature
refractory. Before initid firing of the
unit, these should be checked for any
damage that may have occurred during
Universal Boiler Works, Ine. Chpt. 3
- Start-Up & Opemion of the Model BF HW Blr.
debris and wash with a water hose.
h y hairline
cracks should be wash mated with a
lightweight cement mixture.
shipment of the boiler.
Close bwer handhole cover.
e sure that the relief valvds)
To provide longer life of the rehctory,
it is recommended that the refractory be
cured properly prior to full fim
operation. During Eabricaiion and while
the unit was under instdlatioq the
refractory absorbed a goodly amount of
moisture. This contained moisture must
be driven off slowly to prevent rapid
expansion of the material that could lead
to large uacb and eventual overheating
of the extdor s t 4 surfaces. Please
refa to the separate pnxedtm coming
refractory curing.
valve seatt
If the boilelmonlp is to be boiled
out, connect an overflow pipe to
one of the relief valve connection
openings, This pipe should have a
connection fbr
chemicals as needed during the
boil-out period.
a. Fill the boils with
clean water
jua below the upper dnrm
handhole opening,
t m w must be at l&
Boil-out Refer to the water content of
the W e d boiler shown on Table 3-1.
If the boiler will be d a d with the
system note the &od
amount of
water dative to the required chemicals.
An W i n e solution sbould be used
during the --out
b. Add the cleaning chemicat
wing a pump. Never add the
chemical into the boiler before
adding water.
and add mom water u d l water
begins to flow out the overflow
Chemicals used for b o h u t nre
injurious to eym and skin. Refer to
the M a t d l Safety Dab Sheet for
proper safety
equipment and
protection, and required precamtions.
Always wear eye protection and
rubber gloves when handling boil-out
Remove upper and lower drum
handhole covers and inspect dl
internal surfaces. Remove any
c. Close the upper hmdhole cowr
d. Recheck all b u m controls and
fight the burner. M e sure the
burner is in the manual firing
position and at low fue. Fire
the boiler intermittentIy until
the water reaches the boiling
em When boiling temperature has
been established, hold at this
point for at least five hours. If
Star-Up & Operation of the Model BF HVV Btr.
the rehctory is being cured,
keep the curing process in mind
k. Replace the handhole covers
with new gaskets and attach the
Universal Boiler Works, [nc, Chpt. 3
relief valve(s).
during the boil-out period.
f. During the boil-out period,
open the bottom drain wive
once every hour. Allow this to
remain open for a count of 5,
then close, Add more water
until overflows. Check the
alkalinity periodically. When
the alkalinity M b below 3000
ppm, add more chemical
g. Intermittently, add more water
to d o w an overflow of witer
to c a y off surface impurities.
Continue this process until the
water clears.
h. The time Wod for boil-out
wit1 vary in &tion to ttae size
if the boiler, and as well, if the
dactory is being 4.
Generally, a boil-out should
take no more than 24 hours for
the largest units (300 hp to 800
hp) and las than 12 hours fbr
s d e r units. Cleanliness of
the waterside is c d h m d by
water clarity.
i. Upon completion, shut the
burner off and allow the water
temperature to drop to
approximately 120' F. Drain
the boiler.
j, Remove the handhole covers in
both drums and wash the
waterside surfaces. Inspect the
surfaces and if not clean, repeat
the boil-out procedure.
If the boiler will be placed into
operation shortly after boil-out,
fill the unit with clean treated
water and fire the unit to reach
at least 180°F, If the unit will
not be used right away, prepare
the unit for lay-up storage.
If the boiler and system will be
cleaned jointly, an overflow pipe
may be used, with a shut-off cock,
to check the cleanliness of h
system water.
However, the
addition of the cleaning chemicafs
should be introduced via a shot
f d w or via the expansion tank.
Make sure the boiler relief
valve@) is removed duriug
systedboiler cleaning
Follow the burner firing and
rehctory curing n d o m as
desai'bed for boiler only b i l out.
E. Refractory
The reeactory used in the construction
of the Model SF watertube boiler has
beam chosen for the intrinsically good
insulating properties and longevity and
reduces maintenance andlor repair
To avoid rapid expansion of moisture
contained in the refractory, caused by
immediate full load f ~ n g
the following
refractory curing schedule should be
accomplished. Once the curing process
has been accomplished, normaloperating procedures can be permitted.
Universal Boiler Work, Inc. Chpt. 3
Start-Up & Operation of the Mudel BE W Blr.
Set the burner to the low fire position.
The curing proccss will follow a period
of low fire operation with an increase in
firing rate throughout the curing period.
Hour Q
Hour 2%
Fire for 5 minutes,
dtmatively. (5
on, 10, off, etc.)
Fire for 5 minutes,
minutes, stop for 5
approximately 314
of an hour then
slowly turn down
boil-out is being
continue with the
to low fire.
Note: On units below 150 horsepower,
the cuing time can be reduced by 50%.
This means that during hour 4, the firing
rate may be increased proportionately
throughout the hour.
Note: One the curing process has
begun, it should not be intmpted,
d t d v e ly.
Hour 4:
rate between low
md mid range;
minutes, a d off
for 5 minutes
Continue firing at
the rate noted in
hour 4.
Hour 6;
f i g
rates at mid-point
firing as noted in
Hour 4.
rates to 75% and
continue f i g .
fate to 10% and
Note: Before boilor rehctory
curing is undertaken, the bumex should
Ix properly adjusted for proper fuel
input and keYair ratio.
fuel/& ratio can cause incomplete
mbustion and sooting of the fieside
sudiaces. Refer to the burner mantlaI for
p r o p lwlmr adjustments.
Refer to the burnerhoiler-wiring
diagram, the combustion safeguard
control manual, and the burner marmd
fbr specific refereace to the combustion
safeguard control furnished. A more
detailed discussion is contained in the
technical information booklet covering
the specific combustion safeguard
control. However, the folIowing is an
overview of the burnerhoiler sequence
of operation
The burner and control system are in
starting condition when the following
conditions exist.
Universal Boiler Works,
Inc. Chpt. 3 --Up
Boiler and system are filled with water
and the low water control probes or float
control confirm correct water level. The
aperating limit temperature control and
high limit temperature arc below their
respective cut-off settings, All entrance
switches are closed and power is present
at the line termids of the forced draft
fan starter. Powa must
be p t e m
to the oil pump starter fbr remote oil
pumps far burners operating on oil fuel.
The sequence of operation does not
attempt to corrdate the d o n of the fuel
supply system, system pump inhx1odq
combustion air damper interlack$ atld
p e d n specifically to the action of the
combustion s d e g w d -1.
1. C i i t and Interlock Co&
The burner control circuit is a *wire
system designed fm 120 volt, single
phase, 60 hertz, altemahg current.
Control circuit power is extended to the
combustion d b g u a d terminals Ll and
LZ and simultaneously, to the burner air
inlet damper motor.
The controls used in the inlet circuit vary
depending upon the fud - oil or gas and the specific requhments of
appliwble regulatory budies. Refer to
the wiring diagram to determine the
controls providedThe controls
normally used are:
-Control Power On-Off Switch
-Gas-Oil Switch (Combination
Fuel Units)
-Operating Limit Temperature
-High Limit Temperature Control
-Low Water Cutoff Control
-Low Gas Pressure Switch
t!k Operation of the Model BF HW Blr.
-High Qas Pressure Switch
-Proof or Closure Valve End
Controls used in the running interlock
circuit are:
Blower (Forced Draft Fan) Motor
St a r n
Combustion Air Proving Switch
With the programmer energized, the
f *Purged Period
When the burner control switch is placed
in the on position, power is routed
through the limit controls and the limit
proving circuit, intend to the
combustion safeguard control is proven,
provided that dl limits are made- W
the limits proven mi if supplied, the gw
fuel valve md switch proves that the gas
valve is cIosed (M valve h r l o c k
circuit), the fbrced draft -fan
Internal circuitry provides power to the
burner air inlet damper motor and the air
damper drives to high airfIow position.
Depending upon code requirement$ the
damper will go to the fill open position
and if n high fire position switch on the
damper has been furnish4 the switch
must be made before the combustion
control will allow the damper to return
low fire position for sid for ignition.
Provided that the damper has proved f i I l
airflow and the running interlocks have
been proven closed (combustion air
interlock closed) the combustion
safkguard must sense that the damper
has returned to the low fire start position,
Universal Boiler Works, Inc. Chpt. 3
- Start-up 8Z
This is accomplished via the low fire end
switch on the damper motor. When this
switch closes the combustion safeguard
will begin the sequence for ignition.
Operation of the Model BF
KW Blr.
has retimed to low fire and the
demand h a been satisfied, the operating
limit control will open and the burner
will turn off and commence a short post
air purge period,
Ignition Perid
Upon proof that the dampw motor is at
low fire (damper at minimum airflow),
internal circuitry of the combustion
safeguard energizes the ignition
The burner's ignition
transformer is energized and the p a
solenoid valve is opened md the pilot
f l m e is ignited.
When the f l m e detector senses a
sufficiently stmng pilot h e witbin a
10-second period, the main fud vdves
are energized and main flame is ignited.
The flame scamex must detect main
flme within a 15-second trial period so
that the combdon w e a c e rmry
proceed. If flame is not sawxi, the
will cause an
at has been
comp1eted, the f o r d draft fan will shut
off automatically and the c 0 m W o n
Bafeguarcl will await the next signal: for
load demand and restart the above
sequence autornaticaIIy.
The combustion safeguard coatrol will
prevent start-up or ignition if the pre
ignition or sirflow i n t d o c b open. The
controls lockout switch must be
manually depressed following a safety
shutbwa A b r t coot down period is
necmsary before the swit~hbutton a m
be depressed and @on
automatic shutdown of the fuel vdires
and cycle the burner to the off position
and energize the atarm circuit.
Automatic Lord Response
When the main flme has been
established, the combustion safeguard
places the damper motor into the auto
~ n s ethe boiler's modulating
temperature and Iimit controls.
Depending upon the position of the
modulating temperatwe control the
burner wilI modulate fiom low to high
fie in response t o system demand.
As the hating demand becomes less, the
damper motor will automatidly drive to
a lower firing rate and eventualtlly, as
demand becomes satisfied, burner will
return to the low fire position. When the
The cause for loss of flame or my
unusual condition should be investigated
and corrected before a m q h g to
Please note that the combustion
sdkguard control is a solid state device
with no moving parts.
attempt to by-pass the control nor
attempt to repair if found to be
defective. Tampering with the control
or bypassing the sequence can lead to
injury. If the control does not respond
properly contact your l o d saledservice
representative or Univwsal Boiler for
Chapter 4
Model BF Hot Water Boiler
Boiler Controls, Operation and Adjustments
B. Control Purpose
This chapter pertains to the controls furnishad
on the boiler. Please refer to the burner manuai
for control settings pertinent to the s p i f i ~
burner furnished with the boiler Boiler d
burner controIs must be ptoperfy set f;w &a aad
reliable operation of the pcrcbge
The controls selected for the boiler are fbr the
safe and reliable operation of the boiler.
Tampring with, improper setting or bypassing
the controls could lead to seriously waf&
conditions, and will void the wmm@ of the
coatrot and boiler. Each device has a spcific
purpose in proper operation or serves as a safety
device to prevent equipment or personal injury, -
The specific project may inelude controls not
listed in this e m . Please rcfwtw?heBiIl of Materials for controls -that m
y be installed:
external to the boiler. Other devices may
interface with the boilerlbrttner controls - and
their operation-,.and,:
,adjustments;. ~ e n-:.-,c :: ~ ~ .
?This cbntrol isan auto.,?:+.
-9pah,interke with the opmting-mntmls-of+~~.
open or closure switch to permit. the'
~ . boiler
and burner. Refer to the individud
boilerhmw start sequence to ooc~r. Via a .
items inc1uded.a~an ,&du~.to.fhk *&i<
.- :
sensing element located in t
k upper dnrm;-the
control switch will close when water
temperature Mls below the corrtrols' "on" setA. Controls, General
point When water temperature reaches the
controls' "off' setpoint, the controls switch will
The controls furnished with the Model BF boiler
open to shut the burner off.
standardty incIude:
Operating Limit Temperature
Excess Temperature
Burner Positioning
Low Water Cutoff
Water Temperature Gauge
Pressure Gauge
Pressure Relief Valve
Individual manufacturer's catalogue cut sheets
are included at the end of this chapter for these
"-t gauges and
relief valve are pre-set and
~ ~ u i no
r eadjustments.
- Sometime referred to as
the High Limit Control, this device is 'provided
as a safety controt to discontinue aperation if the
operating limit control fails to open. NormaIIy
the control i s a mechanical reset device although
it may have been wired to affect a manual reset
via the Combustion Safeguard Control. This
controls' set-point is always set above the setpoint of the operating limit control but below the
maximum operating temperature limits of the
sys tern.
Burner Positioning - This control responds to the
positions the burner firing
system demand and
Untverual Bo~lerWorks. lnc.
Chapter 4 Model BF Hot Wlitur Boiler Controls, Adjustment. Opration
rate accordingly, On units from 80 horsepower
and above, the control is a modulating t y ~
while on units below 80 horsepower tho control
i s z hlghllow positioning control as a standad.
for desired owrating tempnture,
The /
operating r a n g for this control 1s 110-240 ( '
degrees, with and adjustable differential from 5 .
When heat is required, this control wilI affect
the relative firing rate of the burner, depending
Adjustable Direrential This is the temperatum
difference between the on off operation of the
control. For example, if the open switch set
point is 190 and the differential is 25, the switch
will close when the temperahue drop to 175.
to 30 degrees F.
upon the heat requirement in the system.
Relative to the demand, this control will signal
the burner firing rate at low fire or high fire or
somewhere in between. On full modulation
operation. the contrul wilt pennit the burner to
be positioned relative to tracking the demand
rate of the system r e q u i m When dtmaad
is dsfied, the control will sigd tbe burner W
drive to the low fire psition before 9bWown.
Minimum Set Point Under no circumstances
will UBW accept a control set point below 160
and a differential
than 20 d e w at this
set point
Low Water Control This &vice is b h b e d to
prevent burner operation if a low water Ievel
occurs in the boiler. N o d l y a hot water
has no operating water level as the boiler must
be &lf
at all times for safe opmtbn
However this control if fUrnishad as a
device, if for wme reason water f b w is'
prevented a d water is removed from the unit by
some means during operation It is not however
a device that p r o w sufficient flow through the
Minimrn D
~ - UBWnRco~ Wt
the difkmtid be no less t b n 10 degrtp for the
opatiog Limit oonml. A m w e r # i f f a
may interfen with proper circdati& through
the boiler to keep the btgt transfer rates p p r -
The device [stmdardly] is an h t e d probe
while a float actuated control is optional. When
s probe is fumishd, concot cdwtivity of b
water permits continuity between the sensing
probe and ground. So long as this conductivity
permits current path completion, the control will
permit burner operation to begin or to continue.
When the required operstjxig
temperature of the system has been verified, turn
the dial on thc
to the ofset
point. Verify the designed return water
temperature and be certain that the differential is
not greater nor less than noted atibve. The
control set point should IR approximately 10
degrees above the system required t e m p t u r e ,
that is, if the system is to maintain 200 degrees
F.,set the operating limit control @ 210 degrees
H g L L h l This control should be set at a
minimum OF 20 da b m the operating
C. Operation and Adjustment
limit control. NOTE: For a 30 psi relief valve
setting, this control must not be set above 2400
Refer to Figure 4-1
Owrating Limit Control - Honeywell L4008
Series is the standard control, Refer to the
systt m temperature requirements for the project
CotltCal For full modulating burnet
operation, this control positions the dpmpcr (
Unlvrrsal Boilcr Works. Inc
Chapter 4 Mode! BF Hot Water Boiler Controls. Adjustment. Owration
[n normal owration, the burner will shut down
whenever the tempcrarure reaches setting A.
The switch in the opratiny limit control wilt
o p n . When the tempemure drops to 8 (setpoint minus differential), the operating limit
control switch closes and the burner is cycled
on. At this set-point, the modulating control will
position the burner's damper motor at low fire.
If the toad demand exceeds this low fire set
point, the modulating control will signal the
damper motor to drive the burner toward more
fuel input. As the demand increases, the
modulating control will move toward point D
and the burner wilt respond to fire at an
motor tiom minimum fire to maximum rate. It's
- tting is relative to the set point of the operating
u r n i t control.
There are two adjustments required; one for the
set point (temperature to be maintained in the
system); one for the modulating range or span in
which the burner will modulate between low
and high fire. Please note that the operating
limit control must be set higher than the set
point of the modulating control, to prevent the
boiler from turning off at high fire or prior to its'
low fire position.
Example: Desirad system temperature to be
maintained is 1800 F. Turn the controls' dial to
the 180 degree mark and turn the proportioning
range adjustment wheel (located on the side) to
20, This setting mjmvides,
a modulating range between 170 and 190. With the opmting limit
control set at 200°, this allows the burner to
' drive .to$he, l o w : h positionfor:propetr
iutoff as the t e m p m e nears this set point .,,;
increased mte to its maximum rate. Whenever
the load demand changes, the firing rate will
change accordingly,which is commonly refared
to as rnodulatedfiring.
Never set the O-ng
Limit Controb set:point?;
at the same setting as the ModuIating Control or-below the set point of the Modulating Control.
Set points and throttling ranges may have to be
readjusted after the initid settings to provide
proper system controt, and the above is noted as
a guide only. Consideration must be given to
system three-way valves and Building or Energy
Management Systems. Proper interface must be
accomplished so that the boiler is not turned off
inadvertently at high fire.
Figure 4.1 depicts the relationship between the
operating limit controt and the modulating
control. The burner will be on whenever the
temperature is below point I3 and off whenever
the ternprature is above Point A. The gap
between Points A and B represents the on-off
of the operating limit control.
Point D represents the maximum firing rate of
In the event temperature drops
further. from this set point, either the load,.l
the rating of the bumerhiler, . or
i n ~ ~ c i e fuel
n t flow has marred.
the burner.
Although a gap is shown between B and C,these ,.
points may well coincide if required by load
conditions. When set as shown, the burner wiH
tK in a Iow fire position upon restart and wiIl
fire at that rate for a short period of time before
falling temperature requires an increase in the
f i n g rate. From the illustration one can see that
this recommended operation will not be
achieved if setting C overlapped point B. In that
event, upon a restart, the burner would drive to a
higher firing rate immediately.
When firing a cold boiler, it is recommended
that the burner be kept under manual flame
control until normal operating temperature is
approached. The fuel input may be increased
gradually via the manuaI flame control and the
manual auto switch in the manual position.
Univenal Boilcr Works. Inc.
Chawr 4 Modcl BF Hot Water Boilur Con(m*, Adjustment, Opcrath
required above these points, consult with the
:a1 Boiler Inspctor and UBWNniversal.
The reason why a boiler should not optrate
above 240 degrees -ins
to the set-point o f
the operating rimit control. It is against code to
have the excess water t e m p h l r t control set
higher than 250 degrm. At this set-point, tht
operating limit controt d i f b m h t is H c i e n t
for proper operation.
When initially mng a newly installed boiler or
when bringing an idle boiler on tine with
operating boilers, the idle boiler m u # be
pressequal to the system and elk boilers before adding it to the system.
We recommend.that a ~ o r n e t ebe
r btdled:~.~
, in the retun -line+i:koindicate.. .return.,
water, . ,.
temperature. if
Vat-have not a.
instaIled, it will k U c u I t .tu..ascertain. p r o p: I* . . , .
flow into ~ . b o i l ~ P h ~ ~ .,,.-.:%L.
~ .a:,;.~ ..,;,~ .......
.:,:: , ,
. .~ ~ .
.-c temperatwe,d i ~ ~ ; ~ : t h e ;>' s. u :*~ ..
and returnmater:' . - , . .
When the idle boiler has been bmught on line, .
make certslin that:the air vent kutili;tedrto.expel. *
any entrained air within,the uppc drum,
. .:,.
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