Burnham 8H, 8HE Owner's Manual
Commercial Boilers
MULTIPLE - MODULAR
MANUAL
FOR GAS - FIRED BOILER
SERIES 8H / 8HE SIZES 5 THRU 10
This manual must only be used by a qualied heating installer/service technician.
BEFORE installing, read all instructions in this manual and all other information
shipped with the boiler. Post all instructions and manuals near the boiler for
reference by service personnel. Perform steps in the order given. Failure to comply
could result in severe personal injury, death or substantial property damage.
81416022R1 - 3/15
www.burnhamcommercial.com
Price - $5.00
1
IMPORTANT INFORMATION -
READ and save these instructions for reference
Hazard definitions
The following dened terms are used throughout this manual to bring attention to the presence of hazards of various
risk levels or to important information concerning the life of the product.
Indicates an imminently hazardous situation
which, if not avoided, will result in death, serious
injury or substantial property damage.
Indicates a potentially hazardous situation which,
if not avoided, could result in death, serious injury
or substantial property damage.
THIS BOILER HAS A LIMITED WARRANTY, A COPY OF WHICH IS PRINTED ON THE BACK OF THIS MANUAL.
It is the responsibility of the installing contractor to see that all controls are correctly installed and are
operating properly when the installation is complete. The warranty for this boiler is valid only if the boiler
has been installed, maintained and operated in accordance with these instructions.
Indicates a potentially hazardous situation which,
if not avoided, may result in moderate or minor
injury or property damage.
Indicates special instructions on installation,
operation, or maintenance which are important
but not related to personal injury hazards.
DO NOT store or use gasoline or other ammable vapors or liquids in the vicinity of this or any other
appliance.
If you smell gas or fuel oil vapors, do not try to operate the burner/boiler system. Do not touch any
electrical switch or use any phone in the building. Immediately call the gas or oil supplier from a remotely
located phone.
Burner/boiler systems produce steam or hot water in a pressurized vessel by mixing extremely flammable
gaseous, liquid or solid fuels with air to produce combustion and very hot products of combustion.
Explosions, fires severe personal injury, death and/or property damage will result from improper, careless
or inadequate installation, operation or maintenance of fuel-burning and boiler equipment.
2
Improper installation, adjustment, alteration, service or maintenance can cause property damage, personal
injury or loss of life. Failure to follow all instructions in the proper order can cause personal injury or
death. Read and understand all instructions, including all those contained in component manufacturers
manuals which are provided with the appliance before installing, starting-up, operating, maintaining or
servicing this appliance. Keep this manual and literature in legible condition and posted near appliance
for reference by owner and service technician.
These boilers require regular maintenance and service to operate safely. Follow the instructions contained
in the Series 8H/8HE Installation, Operating and Service Instructions.
Installation, maintenance, and service must be performed only by an experienced, skilled and knowledgeable
installer or service agency.
All heating systems should be designed by competent contractors and only persons knowledgeable in
the layout and installation of hydronic heating systems should attempt installation of any boiler.
It is the responsibility of the installing contractor to see that all controls are correctly installed and are
operating properly when the installation is completed.
Installation is not complete unless a pressure relief valve is installed into the specified tapping on the
supply manifold located on top and at rear of appliance - See Section III, Paragraph 33, ‘e’ of the Series
8H/8HE Installation, Operating and Service Instructions for details.
These boilers are NOT suitable for installation on combustible ooring.
Do not tamper with or alter the boiler or controls. Retain your contractor or a competent serviceman to
assure that the unit is properly adjusted and maintained.
Clean boilers at least once a year - preferably at the start of the heating season to remove soot and scale.
The inside of the combustion chamber should also be cleaned and inspected at the same time.
Have Burner and Controls checked at least once a year or as may be necessitated. Do not operate
unit with jumpered or absent controls or safety devices. Do not operate unit if any control, switch,
component, or device has been subject to water.
3
Appliance materials of construction, products of combustion and the fuel contain alumina, silica, heavy
metals, carbon monoxide, nitrogen oxides, aldehydes and/or other toxic or harmful substances which
can cause death or serious injury and which are known to the state of California to cause cancer, birth
defects and other reproductive harm. Always use proper safety clothing, respirators and equipment when
servicing or working nearby the appliance.
These boilers contain very hot water under high pressure. Do not unscrew any pipe fittings nor attempt
to disconnect any components of this boiler without positively assuring the water is cool and has no
pressure. Always wear protective clothing and equipment when installing, starting up or servicing this
boiler to prevent scald injuries. Do not rely on the pressure and temperature gauges to determine the
temperature and pressure of the boiler. This boiler contains components which become very hot when
the boiler is operating. Do not touch any components unless they are cool.
All appliances must be properly vented and connected to an approved vent system in good condition.
Do not operate boilers with the absence of an approved vent system.
These boilers need fresh air for safe operation and must be installed so there are provisions for adequate
combustion and ventilation air.
The interior of the venting and air intake systems must be inspected and cleaned before the start of the
heating season and should be inspected periodically throughout the heating season for any obstructions.
Clean and unobstructed venting and air intake systems are necessary to allow noxious fumes that could
cause injury or loss of life to vent safely and will contribute toward maintaining the boiler’s efficiency.
These boilers are supplied with controls which may cause the boiler to shut down and not re-start without
service. If damage due to frozen pipes is a possibility, the heating system should not be left unattended in
cold weather; or appropriate safeguards and alarms should be installed on the heating system to prevent
damage if the boiler is inoperative.
This boiler is designed to burn natural and/or LP gas only. Do not use gasoline, crankcase drainings, or
any oil containing gasoline. Never burn garbage or paper in this boiler. Do not convert to any solid fuel
(i.e. wood, coal). All flammable debris, rags, paper, wood scraps, etc., should be kept clear of the boiler
at all times. Keep the boiler area clean and free of fire hazards.
Float type low water cutoff devices require annual inspection and maintenance. Refer to instructions in
Section V, Paragraph 7 of the Series 8H/8HE Installation, Operating and Service Instructions for inspection
and cleaning instructions.
All Series 8HE cast iron boilers are designed, built, marked and tested in accordance with the ASME Boiler
and Pressure Vessel Code, Section IV, Heating Boilers. An ASME Data Label is factory applied to each 8HE
jacket, which indicates the boiler Maximum Allowable working Pressure (MAWP). Each cast iron section is
permanently marked with the MAWP listed on the boiler’s ASME Data Label. The MAWP for all Series 8HE
Boiler is 50 psi (Water Only).
It is common and acceptable practice to install these boilers in lower pressure systems, below the boiler
MAWP. Therefore, in addition to Safety Relief Valves set for 50 psi, Burnham also offers Safety Relief Valves
set for 30 psi (By Special Order Only).
4
Important Product Safety Information
Refractory Ceramic Fiber Product
The Repair Parts list designates parts that contain refractory ceramic fibers
(RCF). RCF has been classified as a possible human carcinogen. When
exposed to temperatures above 1805°F, such as during direct flame contact,
RCF changes into crystalline silica, a known carcinogen. When disturbed as a
result of servicing or repair, these substances become airborne and, if inhaled,
may be hazardous to your health.
AVOID Breathing Fiber Particulates and Dust
Precautionary Measures:
Do not remove or replace RCF parts or attempt any service or repair work
involving RCF without wearing the following protective gear:
1. A National Institute for Occupational Safety and Health (NIOSH)
approved respirator
2. Long sleeved, loose fitting clothing
3. Gloves
4. Eye Protection
• Take steps to assure adequate ventilation.
• Wash all exposed body areas gently with soap and water after contact.
• Wash work clothes separately from other laundry and rinse washing
machine after use to avoid contaminating other clothes.
• Discard used RCF components by sealing in an airtight plastic bag. RCF
and crystalline silica are not classified as hazardous wastes in the United
States and Canada.
First Aid Procedures:
• If contact with eyes: Flush with water for at least 15 minutes. Seek
immediate medical attention if irritation persists.
• If contact with skin: Wash affected area gently with soap and water.
Seek immediate medical attention if irritation persists.
• If breathing difficulty develops: Leave the area and move to a location
with clean fresh air. Seek immediate medical attention if breathing
difficulties persist.
• Ingestion: Do not induce vomiting. Drink plenty of water. Seek
immediate medical attention.
5
LIST OF FIGURES
SECTION 1.0 COMBUSTION, VENTILATION, VENT SYSTEMS ............................. 8
Fig. 1 — 1 Complete Combustion of Natural Gas .......................................10
—2 ConnedSpace,VentilationFromInsideBuilding .....................11
—3 ConnedSpace,VentilationFromOutdoors .............................11
—4 UnconnedSpace,VentilationFromOutdoors .........................12
— 5 Constant Diameter Manifold Vent ..............................................13
— 6 Graduated Diameter Manifold Vent ...........................................14
— 7 Individual Vents .........................................................................15
SECTION 2.0 VENT DESIGN .............................................................................. 16
Fig. 2 — 1 Input vs. Gross Output vs. Net Rating .......................................18
— 2 Recommended Number of Modules ..........................................19
— 3 Input and Dimensional Data ......................................................20
— 4 Tapered Manifold Vent ...............................................................21
— 5 Constant Diameter Manifold Vent ..............................................21
— 6 Dual Takeoff Constant Diameter Manifold Vent .........................22
— 7 Dual Takeoff Tapered Manifold Vent ..........................................22
— 8, 9 Constant Diameter Vent, Back-to-Back .....................................23
— 10 Minimum Installation Clearances ...............................................24
— 11 Free Area of Ventilation Openings ............................................. 24
— 12 Individual Vent Table .................................................................. 25
— 13 Common Vent Table ......................................................... 23 & 27
— 14 Vent Connector Table ................................................................28
— 15 Vent Diameter vs. Chimney Area ............................................... 29
— 16 Area of Masonry Flue Tiles ........................................................30
PAGE
SECTION 3.0 WATER PIPING ............................................................................. 31
Fig. 3 — 1 Water Piping for Parallel Pumping .............................................39
— 2 Water Piping for Primary-Secondary Pumping ..........................40
— 3 Recommended Manifold Piping .................................................41
— 4 Module Water Flow Data ...........................................................42
— 5 Friction vs. Water Flow — Iron Pipe ..........................................43
— 6 Friction vs. Water Flow — Copper Pipe .....................................44
— 7 Equivalent Length of Pipe for 90° Elbows .................................44
— 8 Volume of Water in Pipe ............................................................45
— 9 Compression Tank Selection Table............................................45
— 10 Correction Factor for Compression Tank Selection ...................46
6
LIST OF FIGURES (continued)
SECTION 3.0 WATER PIPING (continued)
Fig. 3 — 11 Net Expansion Factors for Water ...............................................46
— 12 Acceptance Factors for Diaphragm Type Tanks ........................ 47
— 13 Module Data-Water Side ...........................................................47
— 14 Water Piping for Service Water Heater ......................................48
— 15 Service Hot Water Demand, Fixture Units .................................49
— 16 Service Hot Water Flow Rate ....................................................49
— 17 Sizing Factors for Combination Heating/Service Water .............50
SECTION 4.0 GAS PIPING .................................................................................. 51
Fig. 4 — 1, 2 Recommended Gas Supply Piping ................................... 54 & 55
— 3 Gas Pipe Sizing Table ...............................................................56
— 4 Equivalent Length of Fitting & Valves — Gas Pipe ....................56
— 5 Maximum Capacity of Pipe ........................................................57
—6 CorrectionFactorsforSpecicGravity ......................................57
— 7 Support of Piping .......................................................................58
— 8 Moisture and Dirt Trap ...............................................................58
PAGE
SECTION 5.0 CONTROLS .................................................................................. 59
Fig. 5 — 1 Tekmar 261, Two-Stage, EI, for Parallel Piping .........................61
— 2 Tekmar 261, Two-Stage, EI, for Primary Secondary Piping ......62
— 3 Tekmar 263, Two-Stage, EI, for Parallel Piping .........................63
— 4 Tekmar 263, Two-Stage, EI, for Primary Secondary Piping ......64
— 5 Tekmar 274, Two-Stage, EI, for Parallel Piping .........................65
— 6 Tekmar 274, Two-Stage, EI, for Primary Secondary Piping ......66
— 7 Tekmar 268, Two-Stage, EI, for Parallel Piping .........................67
— 8 Tekmar 268, Two-Stage, EI, for Primary Secondary Piping ......68
SECTION 6.0 START-UP AND SERVICE ............................................................ 69
Series 8H/8HE Boilers are NOT suitable for direct installation on combustible ooring.
Refer to the 8H/8HE Installation, Operating and Service Instructions (Part Number 81416021) for Installation
Instructions for Floor Shields that are available and required for combustible oor installations.
7
SECTION 1.0 COMBUSTION,
VENTILATION & VENT SYSTEMS
1.1 INTRODUCTION – The basic principles of combustion
or burning of a gaseous fuel should be reviewed briey
in order for the reader to appreciate the necessity of:
(1) providing adequate ventilation for replacement of
air consumed during the combustion process and the
replacement of air carried out with the products of
combustion, and (2) providing a properly designed vent
system that will effectively convey the gases produced
during the burning process to the outside atmosphere
along with any air diluting the ue gases.
1.2 COMBUSTION – In order for combustion or burning
to take place three things are needed:
1) Fuel-in this case, natural gas or propane.
2) Oxygen-oxygen is obtained from the air which is
approximately 20% oxygen and approximately 80%
nitrogen. Nitrogen is inert and will not burn.
3) Heat-gas will not urn until its temperature is raised
to its ignition point, approximately 1100-1200°F. A
gas burning pilot (open ame) or electrical means
(spark) is used for the initial ignition after which
the ame itself provides the heat needed to sustain
combustion.
If any of the three are taken away, combustion cannot
take place.
Because the mixing of air and fuel is not 100% complete,
more air than is actually needed called excess air must
be supplied to the appliance in order for burning to be
complete. This is shown in Figure 1-1.
If the supply of fresh air is inadequate or is not contin-
ually replenished as it is used up, carbon monoxide (CO)
and Hydrogen (H2) as well as the products of combustion
shown in Fig. 1-1 may be produced. This is undesirable
since carbon monoxide is toxic and some-times lethal
even in small quantities.
In addition to the fresh air required for combustion,
fresh air is also required to dilute the ue products so
that the resultant ue gas temperature is reduced to what
is considered a safe level. Thus, a total of 16 cu. Ft. of
air may be required for each cu. ft. of gas burned, 12.5
cu. ft. for the combustion process and 3.5 cu. ft. for the
dilution process.
1.3 VENTILATION – Fresh air requirements for the heating
plant will vary with the space in which the plant is located
as described and illustrated in succeeding paragraphs.
Reference to free area of air inlets is made in the text
since louvers, grilles, or screens are sometimes used at or
in the inlet and these have a blocking effect. This must
be taken into consideration in order to obtain proper
quantities of fresh air. If the free areas of these devices
are not known, it may be assumed that wood louvers will
have 20-25% free area and metal louvers and grilles will
have 60-75% free area.
For installation in boiler rooms with ventilation air
provided from inside of building having adequate
inltration from outdoors, each opening shall have a free
area of not less than one (1) square inch per 1000 Btuh
of the total input rating of the heating plant and other
fuel burning appliance in the boiler room. See Figure
1-2.
For installation in boiler rooms with ventilation air
provided directly from outdoors, each opening shall have
a free area of not less than one (1) square inch per 4000
Btuh of the total input rating of the heating unit and other
fuel burning appliance in the boiler room. Each opening
should be equipped with a screen covering whose mesh
should not be less than ¼ inch and each opening should
be constructed so that they cannot be closed. See Figure
1-3.
Normally, if the boiler is installed in an unconned space,
an adequate amount of ventilation air will be supplied by
natural inltration. If however, the unconned space is
of unusually tight construction, air from outdoors will be
needed. A permanent opening or openings with a total
free area of not less than one (1) square inch per 5000
Btuh of the total input rating of the heating plant and
other fuel burning appliances in the unconned space
is necessary. If ducts (minimum rectangular area of 3
square inches) are used, they must be the same crosssectional area as the free area of the opening to which
they connect. Screening to cover the openings to the
outside should not be smaller than ¼ inch mesh and
each opening should be constructed so that they cannot
be closed. See Figure 1-4.
Adequate combustion and ventilation air must be
provided to assure proper combustion.
The importance of adequate and proper ventilation
cannot be overemphasized. It must also be
understood that venting and ventilation must always
be considered together. They are both part of the
same system and must balance each other.
If exhaust fans are utilized such as for make-up
air, the make-up air should not be drawn from the
same space that is the source of combustion air for
the heating plant unless adequate provisions are
made to supply additional outside air so that the
space surrounding the heating unit is not under a
negative pressures (less than outdoor pressure).
Blowers should not be used to forcibly provide
ventilation unless controlled to a point where static
pressure in the space in which the heating plant is
located is equal to the outdoor pressure.
8
(continued)
Excess pressure resulting from larger than
necessary volumes of fresh air will cause excessive
dilution of the ue products resulting in low ue
gas temperatures. If lowered below the dew point,
condensation of the moisture in the ue gases
will occur and, if continued over an extended
period of time, will corrode vents, drafthoods, heat
exchangers, and burners.
There are certain elements known as halogens
(uorine, chlorine, bromide, iodine and astatine)
which are utilized in many commercial products
(refrigerants, solvents, spray can propellant, etc.).
If these products must be used near the heating
plant, extra precaution must be taken to obtain
uncontaminated air from the outside, otherwise
severe corrosion will occur in the boiler and vent
system.
When an existing boiler is removed from a
common venting system, the common venting
system is likely to be too large for proper venting
of the appliances remaining connected to it.
1.4 VENTING – As pointed out before, venting is the
process of removing of the ue products. There
are basically two types of venting: atmospheric
(or gravity) and power venting. Further discussion
will be limited to atmospheric vent systems since
it is, by far, the most commonly used and the most
applicable to the Series 8H/8HE modular boilers. The
atmospheric system is composed of numerous parts
and it is necessary to understand the function and
operation of each part in order to properly design the
system.
Do not alter boiler draft hood or place any
obstruction or non-approved damper in the
breeching or vent system. Flue gas spillage can
occur. Unsafe boiler operation will occur.
1.4.1 DRAFTHOOD – The ue outlet of a heating appliance
such as the Series 8H/8HE module cannot be
connected directly to the vent system for the following
reasons:
a) The amount of air drawn thru the combustion
chamber would vary with the height of the vent
pipe. Hence, there would be little or no chance
of maintaining the same air ow rate thru the
appliance for the variety of installation conditions
which invariably are encountered.
b) There would be no way to compensate for variable
wind conditions encountered at the terminal of
the vent. If wind conditions created a negative
pressure at the vent terminal, this negative pressure
would tend to increase the ow thru the vent
system – this phenomena is referred to as updraft.
If the wind created a positive pressure at the
terminal, the ow through the vent system would
be retarded or reversed – this condition is referred
to as downdraft.
c) There would be no avenue of escape for the ue
gases in case the vent became blocked.
d) Flue gases, if undiluted, could reach temperatures
which would create a potential re hazard if the
ue gases were to strike ammable surfaces.
To overcome all of the deciencies outlined above,
an AGA listed vertical to vertical type of drafthood is
furnished with each Series 8H/8HE boiler, see insert
of Fig. 1-5. The inlet opening of the drafthood is
connected to the ue outlet of the boiler, and the exit
or outlet opening of the drafthood is connected to the
riser portion of the vent connector. The inlet and exit
diameter and the stem height of the drafthood are a
function of boiler size since they were determined
only after extensive testing and after certication by
the American Gas Association and by the Canadian
Gas Association. Therefore, THE DRAFTHOOD
MUST NOT BE ALTERED IN ANY MANNER.
1.4.2 VENT CONNECTOR – see Fig. 1-5. The vent
connector is that portion of the vent system which
connects the exit (outlet) of a drafthood of an
individual appliance to the manifold vent (breeching)
servicing two or more boilers. If there is a horizontal
run in the vent connector, this horizontal run is
known as a lateral. Since the vent connector may
enter the bottom or the side of the manifold vent,
the vent connector rise is the vertical distance from
the drafthood outlet to the lowest level at which
the connector enters the manifold. A slip joint or
drawband, as illustrated in Fig. 1-5, will facilitate
installation of connectors as well as replacement
of parts in that portion of the system should it ever
become necessary.
1.4.3 MANIFOLD AND COMMON VENTS – see Figs.
1-5, 1-6. A manifold vent or breeching is a horizontal
extension of the vertical common vent. The common
vent, which is sized to handle the total load when
all modules are operating, can be of masonry
construction, single-wall metal pipe, or type B Gas
Vent Pipe – consult local codes. A UL Listed vent
cap should be installed, if possible, at the exit of the
common vent to assure full vent capacity and freedom
from adverse wind effects.
Total vent height is the vertical distance between
the exit of the common vent and the exit or outlet
of the drafthood. Regardless of the calculated total
vent height required for capacity, all vents must be
correctly terminated a sufcient distance above the
roof surface and away from nearby obstructions,
see Figs. 1-5 and 1.6. This is to avoid adverse
9
wind effects or pressure areas which may reduce
or impede vent ow. This does not imply that
terminations at these locations will assure proper
venting in every instance. Because winds uctuate
in velocity, direction, and turbulence, and because
these same winds impose varying pressures on the
entire structure, no simple method of analysis or
reduction to practice exists for this complex situation.
Manifold vents may be run horizontally or sloped
upwards toward the common vent. Slope should not
exceed ¼” per foot unless required otherwise by local
codes. Regardless, minimum vent connector rise as
determined for each appliance must be maintained.
Manifold vents may be of constant diameter (Fig. 1-5)
in which case they are of the same size as the common
vent or its equivalent. Manifolds may also be tapered
(Fig. 1-6) for the actual input to a particular section of
the manifold. Difference in operating characteristics
between properly sized constant diameter manifold
vents or tapered manifold vents are negligible and
choice is usually dictated by convenience and cost.
1.4.4 INDIVIDUAL VENTS – Economics thru the use
of smaller vent pipe and the elimination of ttings
could dictate the use of an individual vent system for
each module (see Fig. 1-7) rather than a combined
vent system. If the individual vents are of the proper
diameter and the total vent height is a minimum of
5 ft., the systems are self venting and more reliable
than a combined vent system since, in the latter, it is
impossible to anticipate all contingencies.
1.4.5 VENT AND CHIMNEY MATERIALS AND
CONSTRUCTION – The materials of construction for
vents and chimneys include single-wall metal, various
multi-wall air and mass insulated types as well as
masonry, which could be precast or site constructed.
In many instances, national or local codes will govern
what type may be used. Where choice is possible,
many advantages can be listed for the UL Listed
double wall metal type B vent:
1) warm up is faster with type B vents than vents
having greater mass
2) type B vents permit closer clearance to
combustible material than single wall metal vents
unless special precautions are taken with the latter
3) type B vents are less prone to condensation and
corrosion than single wall metal vents
4) type B vents are lightweight, easy to handle and
assemble
Manufacturer’s instructions relative to installation
of their product should be followed as long as they
comply with the National Fuel Gas Code and/or local
codes. Some items to consider are:
1) support of lateral runs so that vent pipe does not
sag
10
COMPLETE COMBUSTION OF NATURAL GAS
FIGURE 1-1
CONFINED SPACE, VENTILATION AIR PROVIDED
FROM INSIDE OF BUILDING
FIGURE 1-2
CONFINED SPACE, VENTILATION AIR PROVIDED
FROM OUTDOORS
FIGURE 1-3
11
2) support of common vent where it passes thru a
ceiling or roof
3) clearances to combustible material – use of
thimbles
4) restops
5) ashing and storm collars
6) guying or bracing of common vent pipe above roof
7) securing and gas tightness of joints
8) lightning arrester if top of metal vent is one of the
highest points on the roof
9) proper termination of vent connection at masonry
chimney – vent should enter chimney at a point
above the extreme bottom of chimney – vent
should be ush with inside of chimney and sealed
(see Fig. 1-5)
10) never connect a gas vent to a chimney serving a
replace unless the replace has been permanently
sealed
11) never pass any portion of a vent system thru a
circulating air duct or plenum.
12
UNCONFINED SPACE—TIGHT CONSTRUCTION
VENTILATION AIR PROVIDED FROM OUTDOORS
FIGURE 1-4
CONSTANT DIAMETER MANIFOLD VENT OR BREECHING
FIGURE 1-5
TWO THROUGH EIGHT MODULES
13
GRADUATED DIAMETER MANIFOLD VENT OR BREECHING
FIGURE 1-6
TWO THROUGH EIGHT MODULES
14
FIGURE 1-7
INDIVIDUAL VENTS
TWO THROUGH EIGHT MODULES
15
SECTION 2.0 VENTS
Inspect existing chimney before installing boilers.
Failure to clean or replace perforated pipe or tile
lining will cause severe injury or death.
2.1 Vents, or breeching ducts, are generally less exible
in design location than are water pipes, gas pipes
or electrical lines. To avoid conicts for a given
location, design and layout the vents in this section
before proceeding to other sections of this manual.
2.2 Obtain a scaled drawing of the boiler room. Note the
oor size, ceiling height, exterior walls, and chimney
location, if provided.
2.3 Determine the input required to the system. It is
recommended that the heating load be determined by
an accurate calculation of the heat loss of the structure
using methods contained in the ASHRAE Guide. If
service water is to be added capacity as described in
paragraph 3.13 of this manual. The boiler capacity
so obtained is net rating to input. Record the input
required on the boiler room drawing.
2.4 Using Figure 2-2 for the input found in 2.3 above, nd
the number of modules recommended. Those module
combinations shown represent the best selection for
lowest rst cost. Other combinations may be selected,
within the following guidelines:
1) Modules using a sequencing control system, such
as Tekmar described in Section 5.0, should not
vary by more than one size.
2) Modules using a combined vent system should not
vary by more than one size.
3) The combined vent sizing procedures in this
section are based on a maximum of eight modules
using a common vent system. If it is desired to
serve more than eight modules with a common
vent system, the specic requirements should
be referred to the BURNHAM COMMERCIAL
Application Engineering Department.
Refer to Figure 2-3 for individual module inputs.
2.4.1 Sketch on the boiler room drawing the approximate
location of the modules. Figures 2-4 thru 2-9 show
several layouts that can be used depending on the size
and shape of the boiler room and chimney location,
if provided. Refer to Figure 2-3 for dimensional data
on individual modules. Select the layout which best
ts the boiler room. Bear in mind that for combined
vent systems it is desirable to keep horizontal laterals
as short as possible. On a combined vent system for
which a xed chimney is provided, it is desirable to
place the rst module close to the chimney.
2.4.2 If the factory fabricated water manifolds are to be
used, 805H, 806H, and 807HE modules should be laid
out with 28½” module spacing and 808HE, 809HE,
and 810HE modules should be laid out with 40”
module spacing. If an 807HE and an 808HE module
are to be connected to a common manifold, use the
longer manifold with 40” spacing. Otherwise, any
module spacing that allows at least 1 inch jacket –tojacket spacing if acceptable, pending local or state
code requirements that may require greater module to
module spacing.
2.4.3 Refer to Figure 2-10 for minimum clearances around
modules to combustible materials and for service
access. CAUTION: Local re ordinances may be
more restrictive and should be complied with.
2.5 One of the serious errors made in layout of a boiler
room is the failure to provide sufcient ventilation
air. Insufcient ventilation air will cause incomplete
combustion, poor ignition, accumulation of soot in
the boiler, or the production of toxic gases. Many
service calls for dirty boilers, nuisance lock outs,
noisy ignition, or obnoxious odors are traceable to
insufcient ventilation air. Use Figure 2-11 at the
input desired to nd the recommended free area of the
ventilation opening required. Reference to Figures
1-2 thru 1-4 should be made in order to understand
the types of installations described in the headings
of Figure 2-11. Record the free ventilation area
required on the plans of the boiler room and sketch
the openings like those shown in gures 1-2 thru 1-4
respectively.
2.6 Individual vents as shown in Figure 1-7 are highly
recommended if the job site conditions allow.
Individual vents are particularly useful in boiler rooms
having a low ceiling height. Individual vents are
easy to design and in many cases result in the lowest
installed cost. They also are the most dependable in
operation and less susceptible to condensation than are
combined vents. To size individual vents, use Figure
2-12 with the vent height available, the lateral length,
size of module and type of vent pipe.
2.7 Combined vents will perform satisfactorily if strict
design procedures are followed. Referring to Figures
2-4 thru 2-9, note that a connector rise F of at least
one foot is required. A connector rise F of three feet
is desirable. Thus, to make the desired connector rise
and have space for the manifold vent, the minimum
boiler room ceiling height must be equal to:
32½” Module Height
+ ) Drafthood Height
+ F Minimum Connector Rise
+ CV Manifold Diameter
+ 6” Clearance
= Minimum Ceiling Height
If the minimum ceiling height above is not available,
common vents will not perform satisfactorily and
should not be used.
16
2.7.1 If the minimum ceiling height is available, proceed
to size the common vent CV in Figure 2-13. Enter
the left hand column at the desired total input and
move right to the column corresponding to your
H, least total vent height, and read the diameter of
the common vent. If more than one elbow is used,
increase CV by one pipe size for each elbow more
than one. Proceed to size the connector rise diameter
CN by entering Figure 2-14 at H available and move
right to the column headed F. On the line for available
connector rise move right to the CN columns headed
by the module sizes selected in 2.4 above. Read the
connector diameter(s). Record these sizes on the
plans of the boiler room.
2.7.2 If a tapered or graduated manifold vent is desired, use
the same procedures above for sizing the intermediate
manifold diameter but for the total input of the
modules served by intermediate tapered or graduated
manifold vent.
2.7.3 Within Figure 2-12 are several entries of NR.
This means that the combination involved is
not recommended. The most common reason
for a combination to be designated NR is that
condensation inside the vent pipe is likely to occur.
This is particularly true of single wall vent pipe.
Combinations outside the shaded area in Figure 2-13
are also not recommended for single wall vent pipe.
Additionally, single wall vent pipe should not be
used with ve or more modules because the dilution
from the unred modules plus the lower surface
temperature of single wall pipe makes condensation
and the resulting corrosion very likely.
2.8 If a masonry chimney is desired, the minimum cross
sectional area of the chimney is found in Figure 2-15
as a function of the vent diameter. Figure 2-16 shows
the area of standard chimney tiles by size.
2.9 The following is an example of the recommended
design procedures.
Example: A 3 story apartment house needs a total
boiler capacity including service water hating, of
1,849,500 Btu/Hr net rating. The boiler room is in
a one story added portion of the building, of noncombustible construction, similar to Figures 1-6 or 1-7
and is 20 feet long, 10 feet wide with a clear ceiling of
12 feet. No chimney is provided. Select and size the
vent system.
1) Refer to Figure 2-1 to convert net rating to input.
Input = 1,849,500 x 1.44 = 2,663,280 Btuh = 2,663
MBH.
2) From Figure 2-2 nd the closest recommended
module combination having an input of 2663
MBH. It is found that an input of 2710 MBH is
the closest size and is composed of ve 809HE and
one 808HE modules.
3) Sketch approximate module locations on the boiler
room plans using minimum clearances recommended in 2.4 above. In this case there is space to
lay-out the ve modules in line along one wall on
40” centers with ample service clearances, front,
rear, and sides, per Figure 2-10.
4) Determine the ventilation areas required from
gure 2-11. It is a conned space but outdoor air
is readily available through vents in the exterior
wall. Use the equation for Conned with Outdoor
Vent:
MBH Input = 2,710. = 677.5 sq. in.
4.0
of free ventilation area required.
5) Select the type of vent system – individual or
combined.
For an individual vent system use Figure 2-12 to
determine the vent size(s). In this example, the
height of drafthoods above the oor = 32½” +
33½” = 66” = 5½ feet. The least total vent height
is calculated from the drafthood up to the top of the
vent pipe which must be at least two feet above the
roof.
12 Ft. Ceiling Height
- 5½ Ft. Drafthood Height
+ 2 Ft. Ceiling Thickness
+ 2 Ft. Vent Extension
= 10½ Ft. total Vent Height, H
Enter Figure 2-12 at H = 10 Ft. and move right to
L = O Ft. Move right to 809HE column and nd
8” diameter for type B pipe and 10” for single
wall pipe. Continue to the right on the same line
to 809HE column and nd 9” diameter for type B
pipe and 10” for single wall pipe. Mark these sizes
on the drawing of the boiler room. If no more
than two 90° elbows are used in the system, no
corrections are necessary. The design is complete.
6) If a combined vent is desired such as in Figure 1-5,
use Figure 2-13 to nd the common vent size, CV.
Enter Figure 2-13 at 2710. MBH input. Move
right to the column H = 10 Ft. and nd common
vent diameter CV = 26” for type B pipe and single
wall is not recommended. Enter Figure 2-14 at H
= 10 Ft. and move right to F = 3 Ft. Move right
and nd connector diameter CN of 12” in the
809HE column and 12” in the 810HE column.
Calculate minimum ceiling height.
32½” Module Height
+ 33½” Drafthood Height, D
+ 36” Desired connector Rise, F
+ 26” Manifold Diameter, CV
+ 6” Clearance
= 11’2” Minimum Ceiling Height
A twelve foot clear ceiling height will work. With
only one elbow, no correction is necessary. The
design of a constant diameter manifold vent is
complete. Mark these vent and connector sizes on
the drawing of the boiler room.
17
7) If a tapered or graduated manifold vent is desired,
such as in Figure 1-6 the horizontal and vertical
portion of the vent serving ve modules is also
complete with 6) above. However, to size the
manifold vent at an intermediate position such as
CV3 in Figure 2-4, use Figure 2-13 for the MBH
Input of the modules served by that position of the
manifold vent. The Input MBH of each module
can be determined from Figure 2-3. In this case
CV3 serves two modules having an input of
920 MBH. Enter gure 2-13 at an input of 920
MBH. Move right to H = 10 Ft. and nd CV3
= 14” diameter. Mark this vent diameter size on
the drawing of the boiler room. Thus a graduated
manifold vent design is complete. It is possible
with this procedure to reduce the manifold vent
size after each module. However, from a practical
standpoint, the cost of ttings may offset the lower
cost of smaller vent pipe.
2.10 All of the above procedure is based on data found
in the ASHRAE Guide, 1975 Equipment Volume,
Chapter 26. The basic chimney equation is expressed
as follows:
(di)² (∆PB)
I = 4.13 x 10
5
x M x (KTm)
0.5
where: I = Operating heat input, BTUH
di = Inside diameter of the common vent or
manifold vent
M = Mass ow input ratio, lb. of products per
1000 BTU of fuel burned. A value of 1.60 was
used based on 5.3% CO2 after dilution. An
additional 15% dilution was added for each
unred module.
∆P = Pressure difference or loss in the system
acting to cause ow, inches of water. Use
0.537 inches water per 100 Ft. of pipe.
B = Sea level barometer used —29.92” Hg
K = Resistance loss coefcients, dimensionless.
Tm = Temperature in vent system at average
conditions, °Fabs.
The serious Engineer should become familiar with the
above basic equation and the range of the variables that
may be encountered. The tables in Figures 2-12 thru
2-14 should not be extrapolated. If system conditions
do not fall within the limit of the tables, vent sizes must
be calculated using the chimney equation above as
described in the ASHRAE Guide.
18
RELATIONSHIP OF INPUT, GROSS OUTPUT, AND
NET RATING FOR SERIES 8H/8HE MODULES
FIGURE 2-1
Total
Input
MBH
Recommended Number of Modules
805H 806H 807HE 808HE 809HE 810HE
Total Input
MBH
Recommended Number of Modules
808HE 809HE 810HE
504 2
567 1 1
630 2
655 1 1
680 2
750 1 1
820 2
870 1 1
920 2
965 1 1
1010 2
1090 2 1
1160 1 2
1230 3
1280 2 1
1330 1 2
1380 3
1425 2 1
1470 1 2
1515 3
1570 1 3
1640 3 1
1690 3 1
1740 2 2
1790 1 3
1840 4
1885 3 1
1930 2 2
1975 1 3
2020 4
2100 4 1
2150 3 2
2200 2 3
2250 1 4
2300 5
2345 4 1
2390 3 2
2435 2 3
2480 1 4
2525 5
2610 3 3
2660 2 4
2710 1 5
2760 6
2805 5 1
2850 4 2
2895 3 3
2940 2 4
2985 1 5
3030 6
3070 3 4
3170 1 6
3220 7
3265 6 1
3310 5 2
3355 4 3
3400 3 4
3475 2 5
3490 1 6
3535 7
3630 1 7
3680 8
3725 7 1
3770 6 2
3815 5 3
3860 4 4
3905 3 5
3850 2 6
3995 1 7
4040 8
FIGURE 2-2
19
Boiler
Model
805H 252 20 10 7 24-13/16 16-1/8 7" dia. x 15 ft. 11.9 680
806H 315 23-3/4 11-7/8 8 27-13/16 18 8" dia. x 15 ft. 13.9 770
807HE 340 27-1/2 13-3/4 9 27-13/16 18 8" dia. x 15 ft
808HE 410 31-1/4 15-5/8 9 30-13/16 20 8" dia. x 15 ft 17.9 950
809HE 460 35 17-1/2 10 33-1/2 22 10" dia. x 15 ft 19.9 1040
810HE 505 38-3/4 19-3/8 10 33-1/2 22 10" dia. x 15 ft 21.9 1140
Input
(MBH)
(1) Specialbaserequiredforinstallationsoncombustibleooring;adds4-3/4"toboilerheight(oortojackettoppanelis37-1/4").
(2) Gas connection size: 1 NPT
(3) Maximum Allowable Working Pressure: 50 psi (Water Only)
(4) Items shown in hidden lines supplied by installer.
"A' "B" "C" "D" "E"
Dimensions (inch)
Recommended
Chimney Size
(Round)
.
Water
Content
(Gallons)
15.9 870
Weight (LB)
Approx.
Shipping
FIGURE 2-3
20
FIGURE 2-4
FIGURE 2-5
21
FIGURE 2-6
FIGURE 2-7
22
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