Bryan Boilers D Series Manual

Installation
Operation
Service Manual
for
Atmospheric Water
Boilers
E-Mail: [email protected] / Internet: www.bryanboilers.com
BRYAN BOILERS
783 N. CHILI AVENUE, PERU, INDIANA 46970
Telephone: [phone] / Fax: [phone]

INSTALLATION INSTRUCTIONS
ATMOSPHERIC
WATER BOILERS
NOTE:
• Please read all of instruction manual before attempting installation.
• Insurance and local or state regulatory codes may contain additional or more stringent requirements
than those contained in this manual. Installation must conform to these codes and any other
authority having jurisdiction.
1.1 BOILER FOUNDATION
Before uncrating, the boiler location should be
prepared. The boiler should set upon a good level
concrete floor. If the boiler is not level or the floor
in good condition, a concrete foundation should
be built, the dimensions larger than the outside
dimensions of the boiler base.
DO NOT INSTALL BOILER ON COMBUSTIBLE
FLOORING. The only exception to this is UL
Labeled F -Series boilers which may be installed
on combustible flooring.
IMPORTANT
If the boiler is installed directly on a concrete floor
where it is important that the floor be kept cool
(such as an upper floor or mezzanine or when
sitting over wiring conduits) set the boiler up on
insulating tile or steel framework so that air may
circulate underneath. For atmospheric gas fired
boilers, it is advisable to build up an insulating
floor under the boiler using high temperature
mineral fiber board at least 1 1/2" thick.
1.2 CLEARANCES
See Table 1 for minimum clearances to wall,
ceilings, or obstructions. The clearances in Table
1 are intended as a general recommendation
only. Local codes must be applied to specific
installations and the minimum clearances
established accordingly. Provisions must also be
made for service, accessibility and clearance for
piping and electrical connections.
Do not obstruct combustion air and ventilation
openings with piping or any other construction. All
boilers must be installed in a space which is large
compared to the boiler. Only UL Labeled F-Series
boilers are suitable for installation on combustible
flooring.
NOTE
ADHERE TO ALL APPLICABLE LOCAL CODES
REGARDING BOILER INSTALLATION AND
CLEARANCES.
1.3 UNCRATING THE BOILER
Uncrate the boiler near its permanent location.
Leave it on the bottom crating until ready to place
it permanently. Leave the plastic shroud on the
boiler until all piping work is complete, cutting
holes in the plastic for access to connections.
Remove the bolts attaching the boiler to the crate
at the underside of the bottom crating. Lift or slide
the boiler off of the bottom crating into position.
Be careful not to tip the boiler up on one corner or
side, which could cause damage to jacket.

MINIMUM CLEARANCES
NOTE: These boilers are intended to be installed in a room which is large compared to the size of the boiler.
They are not intended for alcove installation and are suitable for installation on non-combustible flooring
only.
DIMENSION
D-SERIES F-SERIES1CL-SERIES K-SERIES RV, RW & AB SERIES
WATER/
STEAM
TO 50#
STEAM
OVER
50#
WATER
/STEAM
TO 50#
STEAM
OVER
50#
WATER
/STEAM
TO 50#
STEAM
OVER
50#
WATER
/STEAM
TO 50#
STEAM
OVER
50#
WATER
/STEAM
TO 50#
STEAM
OVER
50#
A 18" 36" 18" 48" 24" 24" 18" 36" 24" 24"
B 24" 24" 48" 96" 48" 36" 48" 24" 48" 48"
CV& CH18" 36" 18" 36" 24" 24" 24" 24" 24" 24"
D 48" 96" 18" 36" 24" 24" 24" 24" 24" 24"
EL& ER24" 24" 18" 36" 24" 24" 24" 24" 32" 32"
1 - F-Series boilers are approved for installation on combustible flooring. Do not install on carpeting.
A - Clearance above boiler
B-Frontofboiler
C
V- Clearance from gas vent, measured vertically above pipe
C
H- Clearance from gas vent, measured horizontally or below pipe
D - From back of boiler
E
L- Left side of boiler
E
R- Right side of boiler
These clearances are general minimum clearances. Local codes may dictate larger clearances.

1.4 BOILER CONNECTIONS
1.4.1 GENERAL
Do not run any pipes along the access panel side of
the boiler. Maintain clearances as shown on the
dimensional drawing for servicing of the boiler tubes.
Provide at least 36" from the gas train and burner,
unless a larger dimension is indicated on the
dimensional. All piping should be designed and
installed to avoid any loadings on the boiler
connections or piping.
1.4.2 FLOW CONNECTIONS
The system supply and return flow connections are
shown on the boiler dimensional drawing in this
manual. A gate valve and union should be on the
boiler outlet and inlet lines. This allows the boiler to be
isolated from the heating system for draining and
servicing. Use a tee, nipple, and cap on the boiler
inlet line to allow inspection and cleaning.
1.4.3 SAFETY RELIEF VALVE(S)
A connection is provided in the top of the boiler for the
relief valve. The relief valve discharge piping must be
the same size as the relief valve discharge opening.
Avoid over-tightening as this can distort valve seats.
All piping from relief valve must be independently
supported with no weight carried by the valve.
1.4.4 EXPANSION TANK CONNECTION
A connection is provided in the top of the boiler for
connecting piping to the expansion tank. This piping
should be installed as to avoid air entrapment in the
boilers.
1.4.5 DRAIN CONNECTION
A drain valve must be installed off of the boiler drain
connection, the same pipe size as this connection, to
allow draining of the boiler.
1.4.6 INDIRECT WATER HEATING BOILERS
When the boiler is to be used only for heating potable
(domestic) water or swimming pool water, the heating
system connections discussed above are capped.
The relief valve connections are still required. Water
connections are made only to the indirect heat
exchanger(s), according to the piping drawing
included in this manual. An automatic boiler fill valve
is provided with the boiler. This valve must be
connected to the fresh water system. With some
units, this connection is made to the heat exchanger
at the factory.
1.5 GAS SUPPLY CONNECTION - ATMOSPHERIC BOILERS
The installation must conform completely to the
requirements of the authority having jurisdiction,
or in the absence of such, requirements shall
conform in the U.S. to the current National Fuel
Gas Code, ANSI Z223.1-1984, or in Canada to
the current Installation Code for Gas Burning
Appliances and Equipment (CAN/CGA B149.1-
M91), or Oil Burning Equipment (CSA B139-
M91), and applicable regional regulations for the
class; which should be followed carefully in all
cases.
Drip leg must be installed on gas supply piping.
Consult the local gas utility company for
inspection and authorization of all gas supply
piping and flue connections.
The regulator vent line must be vented to outside
of building on any boiler equipment with electric
gas pilot ignition.
1.5.1 DRIP LEG
A drip leg, or sediment trap, must be installed in
the gas supply line. See Fig. 1.5A. The gas line
must be connected to a supply main at least as
large as the gas train connection at the boiler.
This connection should be made with a union so
that the boiler gas train components and burner
may be easily removed for service.
1.5.2 GAS PIPING LEAK TEST
After completion of the gas piping hookup, the
installation must be checked for leaks, using a
soap and water solution. Disconnect the boiler
and gas train from the gas supply piping during
any pressure testing.

1.5.3 VENTING OF GAS TRAIN COMPONENTS
Gas pressure regulator - The regulator must be
vented to the outside air, using minimum 1/4"
tubing or pipe. The vent line should terminate in a
downward direction to be free of restriction.
Diaphragm gas valves (V48A or V88A) - The vent
line off of these gas valves must be vented to
outdoors, the same as the regulator.
Normally open vent valves - These valves must
be piped to outdoors using pipe no smaller than
that of the valve.
Gas pressure switches - Vent these switches to
outdoors using a minimum of 1/4" tubing or
piping.
FIGURE 1.5A: GAS BURNER CONNECTION
NOTE: USE PIPE COMPOUND THAT IS RESISTANT TO THE ACTION OF LIQUID PETROLEUM GAS. DO NOT
USE TEFLON TAPE.
1.6 ELECTRICAL CONNECTION
IMPORTANT:All electrical connections must
conform to the National Electrical Code and to all
other applicable State and Local Codes. Atmospheric
boilers require a 120 volt, single phase power
connection plus ground. See boiler wiring
diagram and equipment list for details.
Equipment Grounding - The boiler must be grounded
in accordance with the American National Standard
Electrical Code, ANSI/NFPA #70-1981.
1.7 COMBUSTION AIR SUPPLY
IMPORTANT:Positive means for supplying an
ample amount of outside air, allowing complete
combustion of the gas, must be provided.
Movable combustion air dampers, automatic or
manually adjustable, must be electrically interlocked
with the boiler to prevent boiler operation if the
dampers are closed.
Combustion air openings must never be blocked or
obstructed in any manner.
The boiler room must be at a positive or neutral
pressure relative to the outdoors. A negative in the
boiler room will result in downdraft problems and
incomplete combustion due to the lack of air.
WARNING!
Failure to provide an adequate air supply will result in
boiler damage and hazardous conditions in the
building (fire and asphyxiation hazard as well as
equipment damage).
COMBUSTION AIR: Complete combustion of natural
or propane gas requires approximately ten cubic foot
of air (at sea level and 70F) for each 1000 Btu of
boiler input. In reality additional air is required to
achieve complete combustion. Air is also required for
the proper operation of the appliance draft diverter or
barometric damper. The combustion air opening
recommendations below are designed to provide the
air needed for atmospheric gas fired boilers which are
equipped with either draft diverters or barometric

damper. Combustion air openings for boilers which
are equipped with forced draft burners may be
reduced to 70% of that required for atmospheric gas
fired boilers. This is because the forced draft boiler is
not equipped with a draft diverter (so no air is required
for draft control).
COMBUSTION AIR OPENINGS - AREA REQUIRED:
Openings directly through outside wall -
One opening within 12 inches of the ceiling plus one
opening within 12 inches of the floor. Each opening
must have a minimum free area of 1 square inch per
4,000 Btu of total input of all air using appliances in
the room.
Example: A boiler room having two boilers with
500,000 Btu input would require two openings
through an outside wall, and each opening must have
at least 250 square inches of free area.
Openings through vertical ducts -
One duct in the ceiling plus one duct terminating
within 12 inches of the floor. Each opening must have
a minimum free area of 1 square inch per 4,000 Btu
of total input of all air-using appliances in the room.
Example: A boiler room having four boilers with
250,000 Btu input would require two ducts, one in
ceiling and one terminating near the floor, and each
opening must have at least 250 square inches of free
area.
Openings through horizontal ducts -
One duct opening within 12 inches of the ceiling plus
one duct opening within 12 inches of the floor. Each
opening must have a minimum free area of 1 square
inch per 2,000 Btu of total input for all equipment in
the room. NOTE: No rectangular duct may have a
dimension of less than 4 inches.
Example: A boiler room having 1 million Btu total
input would require two ducts, one in ceiling and one
near the floor, each opening having at least 500
square inches of free area.
Ventilation Air: In addition to air needed for
combustion, sufficient air must be supplied for
ventilation, including air required for comfort and
proper working conditions for personnel in the boiler
room. In colder climates, provision should also be
made to heat the boiler room, if necessary, for
personnel comfort.
CAUTION
Protection from combustion air contamination: Where
corrosive or flammable process fumes are present in
the vicinity of the boiler room or the air stream for the
combustion air supply, it is essential that suitable
means be provided for their safe disposal. The boiler
room and the combustion air supply must not be
exposed to the fumes. Such fumes include, but are
not limited to, carbon monoxide, hydrogen sulfide,
ammonia, chlorine, and halogenated hydrocarbons.
NOTE: Halogenated hydrocarbons are particularly
injurious and corrosive after exposure to high
temperatures.
1.8 CHIMNEY, FLUE PIPE & DRAFT CONTROL - ATMOSPHERIC BOILERS
CODE COMPLIANCE
The installation must conform to the requirements of
NFPA 54, the National Gas Code (ANSI Z223.1-
1984), Part 7, "Venting of Equipment", or to the
applicable requirements of all local building codes. For
factory-built and listed chimney systems (such as type
B vent), consult the system manufacturer's
instructions for correct installation procedures. Gas
vents may be of any of the construction types listed in
this manual. No portion of a venting system may
extend into or pass through any circulating air duct or
plenum.
MINIMUM SAFE PERFORMANCE
Venting systems must be designed to develop positive
flow adequate to remove flue gases to the outside
atmosphere. Guidelines are provided in this manual
and in the National Fuel Gas Code, NFPA 54, for
sizing and design of flue gas venting system. For
additional reference to good practice in vent design,
refer to the "Chimney, Gas Vent, and Fireplace
Design" chapter of the ASHRAE Equipment
Handbook.
OUTSIDE VENTS AND CHIMNEYS
Outside uninsulated single wall pipe is not
recommended for use in cold climates for venting gas-
fired appliances since temperature differentials may
cause corrosion in such pipe, as well as poor draft on
start ups. When local experience indicates that
condensate may be a problem, provisions should be
made to drain off the condensate in the gas vent or
chimney.

ESTIMATING FLUE GAS FLOW RATE (ACFM)
Flue gas volumetric flow rate in SCFM (standard cubic
feet per minute) and ACFM (actual cubic feet per
minute) can be estimated by using the information in
1.8.1A. Divide the Total Input of appliances
connected to the chimney or vent by 1000. Then
multiply this result times the factor listed in the SCFM
and ACFM table. The ACFM data is required for
determining stack exit velocity and induced draft fan
requirements.
ESTIMATING STACK EXIT VELOCITY
First, determine the ACFM for the stack as described
above. Multiply the total ACFM times the Velocity
Factor from the Velocity Table in Table 1.8.1B for the
stack diameter used. The result is the Stack Exit
Velocity in feet per second.
ESTIMATING STACK EMISSIONS
Table 1.8.1C lists approximate emissions of NOx
(oxides of nitrogen) and CO (carbon monoxide). The
table lists both the concentration, in parts per million
(ppm), and the flow rate, in pounds per hour (PPH), of
each compound: Divide the total input of appliances
connected to the chimney or vent by 1,000,000. Then
multiply this result times the value listed in the table for
PPH emissions.
MANUAL REFERENCES
See Figure 1.8.1 for a graphics listing of applicable
sections of this manual for each section of the vent
system.
FIGURE 1.8.1: VENT DESIGN INSTRUCTIONS - REFERENCE
TABLE 1.8.1A: ESTIMATING FLUE GAS VOLUMETRIC FLOW RATE
Approximate Flue Gas VOLUMETRIC FLOW RATE (Per 1000 Btu/hr Input)
(Multiply factor listed times boiler input in MBH)
BOILER TYPE
SCFM Per
1000 Btu/hr INPUT
ACFM Per
1000 Btu/hr INPUT
APPROXIMATE FLUE GAS
TEMPERATURE AT FULL
INPUT
Water & 15# Steam
Boilers
Before Draft
Control
After Draft
Control
Before Draft
Control
After Draft
Control
Before Draft
Control
After Draft
Control
Atmospheric Gas
(Draft Diverter)
Atmospheric Gas
(Barometric D.R.)
0.250
0.250
0.364
0.280
0.462
0.462
0.546
0.474
480F
480F
350F
430F
150# Steam Boilers Before Draft
Control
After Draft
Control
Before Draft
Control
After Draft
Control
Before Draft
Control
After Draft
Control
Atmospheric Gas
(Draft Diverter)
Atmospheric Gas
(Barometric D.R.)
0.250
0.250
0.364
0.280
0.486
0.486
0.602
0.517
550F
550F
400F
500F

TABLE 1.8.1B: STACK EXIT VELOCITY
Estimated STACK EXIT VELOCITY Calculation
(Multiply total ACFM times the velocity factor below velocity in feet per second)
STACK INSIDE
DIAMETER (Inches)
VELOCITY
FACTOR
STACK INSIDE
DIAMETER (Inches)
VELOCITY
FACTOR
STACK INSIDE
DIAMETER (Inches)
VELOCITY
FACTOR
6
7
8
10
12
14
16
0.0849
0.0624
0.0477
0.0306
0.0212
0.0156
0.0119
18
20
22
24
26
28
32
0.00943
0.00764
0.00631
0.00531
0.00390
0.00340
0.00298
34
36
38
40
48
60
0.00264
0.00236
0.00212
0.00191
0.00133
0.00085
TABLE 1.8.1C: ESTIMATING FLUE GAS EMISSIONS
Estimated Emissions (Volumetric Flow Rate Per Million Btu/hr Input)
(Multiply PPH listed times boiler input divided by 1,000,000)
BOILER
TYPE
PARTICULATES NOx CO SOx
PPH per
MBH
PPM PPH per
MBH
PPM PPH per
MBH
PPM PPH per
MBH
PPM
Atmospheric Gas
(Draft Diverter)
Atmospheric Gas
(Barometric D.R.)
N/A
N/A
N/A
N/A
0.115
0.115
70
90
0.120
0.120
75
100
N/A
N/A
N/A
N/A
1.8.2 CLEARANCES
The vent system and draft control devices must
be installed so as to achieve the clearances to
surfaces outlined in Table 1.2.1, Minimum
Clearances chart, in this manual. See also Table
1.8.9 for vent clearances. All clearances must
comply with the National Fuel Gas Code
(NFPA54), and with all
local and state building codes. The clearances
described in this manual are intended to be
general guidelines only, additional requirements
may occur because of local building design
regulations.
1.8.3 PROTECTION AGAINST DOWNDRAFTS
Because of varying wind conditions and proximity
of adjacent structures, the stack termination may
be exposed to severe downdrafts. If this is
anticipated, provision should be made to supply a
stack cap which will prevent downdrafts. The
Breidert type cap will accomplish this.
Downdrafts will cause ignition problems as well
as expulsion of flue products into the boiler room.

1.8.4 BOILER ROOM PRESSURIZATION
The boiler room must be supplied with adequate air
for combustion and for proper operation of draft
control devices (barometric dampers or draft
diverters) as outlined in "Combustion Air Supply",
Section 1.7 of this manual.
WARNING
THE BOILER ROOM MUST BE MAINTAINED AT A
POSITIVE OR NEUTRAL PRESSURE (RELATIVE
TO OUTDOORS) AT ALL TIMES. EXHAUST FANS
OR CONNECTIONS FROM THE BOILER ROOM
TO ZONES OF NEGATIVE PRESSURE (AIR
DUCTS, NEGATIVE PRESSURE ROOMS, ETC.)
WILL CAUSE NEGATIVE PRESSURE IN THE
BOILER ROOM. SUCH CONDITIONS WILL CAUSE
HAZARDOUS OPERATION OF THE BOILER AND
INTRODUCTION OF COMBUSTION PRODUCTS
INTO THE BUILDING AIR.
AND A DRAFT PROVING SWITCH MUST BE
INSTALLED TO PREVENT OPERATION OF THE
BOILER IF THE FAN SHOULD FAIL TO OPERATE.
IT ALSO MAY BE ADVISABLE TO INSTALL AN
AUTOMATIC VENT DAMPER IN THE VENT
SYSTEM TO PREVENT BACKFLOW THROUGH
THE VENT SYSTEM DURING BOILER OFF
CYCLES. SEE FOLLOWING SECTION ON
AUTOMATIC VENT DAMPERS.
IF THE BOILER ROOM MUST BE UNDER A
NEGATIVE PRESSURE AT ANY TIME, AN
INDUCED DRAFT FAN WILL BE REQUIRED.
FURTHER, THE BOILER MUST BE PROVIDED
WITH A "SINGLE ACTING" BAROMETRIC DRAFT
CONTROL - NOT WITH A DRAFT DIVERTER. THE
FAN MUST BE INTERLOCKED WITH THE BOILER
1.8.5 DRAFT CONTROL INSTALLATION - DRAFT DIVERTER
Each atmospheric gas boiler is supplied with a
VERTICAL DRAFT DIVERTER or a BAROMETRIC
DRAFT REGULATOR. THESE DEVICES MUST BE
INSTALLED WITHOUT MODIFICATION. DO NOT
SHORTEN THE COLLAR LENGTH OF A DRAFT
DIVERTER. INSTALL THE BAROMETRIC
DAMPER (IF SUPPLIED) PER INSTRUCTIONS IN
SECTION 1.8.6.
Refer to boiler dimensional for the required distance
from the top of the DRAFT DIVERTER (when
supplied) to the floor. The flue pipe (straight section)
of the diverter must not be shortened or modified in
any manner. The draft diverter must be mounted
directly on top of the boiler as shown in Fig. 1.8.1A.
1.8.6 DRAFT CONTROL INSTALLATION - BAROMETRIC D. R.
FIG. 1.8.6A: BAROMETRIC DRAFT CONTROL
LOCATIONS
FIG. 1.8.6B: BAROMETRIC CONTROL - MG2
BAROMETRIC DRAFT REGULATORS (when supplied)
must be installed such that the minimum distance from
the centerline of the barometric draft control to the top of
the boiler jacket is at least one flue pipe diameter.
Barometric draft controls should preferably be mounted
in the end of a tee as shown in Fig. 1.8.6A. This will allow
better control of minor downdraft conditions.

DO NOT INSTALL A BAROMETRIC DRAFT
CONTROL IN A ROOM SEPARATE FROM THE
BOILER.
The stop and two cover plates are painted in a different
color for easy identification. To remove the stop simply
remove the two screws that hold it to the ring. See Fig.
1.8.6B. To remove cover plates (Item B), bend or break
off the tab that goes through the small hole in the ring.
DO NOT REMOVE THE STOP ATTACHED TO THE
GATE (Item C).
INSTALLATION
Insert the draft control into the collar. The front face of
the control MUST BE PLUMB. The bearing surfaces
MUST BE LEVEL whether the control is on a
horizontal, vertical, or sloping flue pipe. Using a spirit
level, plumb and level accurately. Secure the control in
the collar by tightening the clamping screws. If the
collar is supplied locally, the control may be held in
place by small bolts or sheet metal screws. If the
control has any tendency to sag support it from
overhead.
NOTE: Spill switch provided by others. See wiring
diagram for control point connection.
VERTICAL FLUES
The control is shipped for installation in a vertical flue.
The screw should be left in the top hole of the weight
lever. (Item D)
HORIZONTAL FLUES
For horizontal flues, remove the screw from the upper
hole in the weight lever and insert it in the lower hole.
(Item E)
ADJUSTING THE CONTROL
The control is adjusted to achieve the desired DRAFT
or CO2by adding or removing weights (washer type,
Item F) at the end of the chains. DO NOT MOVE THE
LARGE WEIGHTS ATTACHED DIRECTLY TO THE
GATE (Item G) as they are used only for adjustment at
the factory.
DRAFT should generally be set between -0.02" and -
0.04" w.c. The actual setting must be determined by
taking a CO2reading and a CO reading at the boiler
flue. Reference Table 2.5A for appropriate values.
COMBUSTION READINGS AND DRAFT SETTINGS
MUST BE DONE BY A QUALIFIED BOILER SERVICE
TECHNICIAN.
HIGH DRAFT CONDITIONS
On some installations, because of a high stack, the
draft may be too great to be adjusted using only the
barometric regulator weights. When this occurs, install
a sheet metal baffle through the barometric draft
regulator opening as described in Figure 1.8.6C. The
baffle installation is correct if the gate of the barometric
control is approximately half open while the burner is
operating, and CO2, CO and draft readings are correct.
Barometric
Size (diameter)
Sheet Cut / Form Dimensions
10"
12"
14"
16"
18"
20"
24"
28"
30"
10"
12"
14"
16"
18"
20"
24"
28"
30"
14"
16 3/4"
19 1/2"
22 1/2"
25"
28"
33 1/2"
37"
44"
5"
6"
7"
8"
9"
10"
12"
14"
16"
NOTE THAT THE GATE MUST SWING FREELY
AFTER THE BAFFLE IS INSTALLED.
DO NOT RESTRICT THE BREECHING BETWEEN
THE BAROMETRIC DRAFT CONTROL AND THE
CHIMNEY OR VENT.
CAUTION SHOULD BE USED TO INSURE AGAINST
OVER-RESTRICTING THE FLUE. ALWAYS BE
CERTAIN THAT COMBUSTION IS CORRECT AND A
DRAFT EXISTS AFTER THE BAFFLE IS INSERTED
AND SECURED IN PLACE.
NOTE that the dimension for baffles may vary due to
different types of flue connections and tee sizes.

FIG. 1.8.6D: SUGGESTED BAFFLE
DIMENSIONS
Fig. 1.8.6C: BAROMETRIC CONTROL WITH BAFFLE
FOR CONTROL OF EXCESSIVE DRAFT
1.8.7 ACCEPTABLE VENT TYPES
TYPE B GAS VENTS
Type B gas vents may be used with listed water
boilers and low pressure (15 psig) steam boilers
when provided with a factory supplied draft
diverter. Type B gas vents may also be used
(subject to local approvals) with UL listed and
labelled, atmospheric gas-fired CL series water
boilers and low pressure steam boilers and K-
series water boilers when equipped with a
correctly installed barometric draft control. Type B
gas vents may not be used on high pressure
steam boilers (over 15 psig) or any other Bryan
boilers not specified above. Type B gas vents
should preferably bear the U.L. label. Installation
of these vents must comply with the vent listing,
with the vent manufacturer's instructions and with
complete adherence to the codes and clearances
as outlined previously.
SINGLE-WALL METAL PIPE
Single-wall metal pipe must be of galvanized
sheet or other approved noncombustible
corrosion resistant material, with minimum
thickness per Table 1.8.7, from the National Fuel
Gas Code. Single-wall metal pipe should be
insulated to prevent excessive heat in the boiler
room and to avoid ignition and spillage problems
as well as corrosion from excessive
condensation.
MASONRY, METAL AND FACTORY BUILT
CHIMNEYS
Installation of factory built vents and chimneys
must comply with the vent listing, with the vent
manufacturer's instructions and with adherence to
the codes and clearances as outlined herein.
Masonry or metal chimneys must be built and
installed in accordance with nationally recognized
building codes or standards.
MASONRY CHIMNEYS FOR RESIDENTIAL
APPLICATIONS MUST BE LINED WITH FIRE-
CLAY FLUE LINING (KX C315) OR THE
EQUIVALENT WITH THICKNESS NOT LESS
THAN 5/16 INCH OR WITH A LINER OF OTHER
APPROVED MATERIAL THAT WILL RESIST
CORROSION, SOFTENING OR CRACKING
FROM FLUE GASES AT TEMPERATURES UP
TO 1800F.
EXISTING CHIMNEYS SHOULD BE
INSPECTED FOR UNSAFE CONDITIONS,
SUCH AS DETERIORATED MASONRY AND
EXCESSIVE SOOT OR OTHER BLOCKAGE OR
POTENTIAL BLOCKAGE. SEE ALSO SECTION
1.8.9.
EXISTING CHIMNEYS MUST BE PROPERLY
SIZED FOR THE FLUE GAS LOADING TO BE
USED. THAT IS, IF AN EXISTING CHIMNEY IS
USED FOR A SMALLER TOTAL INPUT THAN
ITS ORIGINAL DESIGN, A LINER OR VENT IS
REQUIRED. THE USE OF A PROPERLY SIZED
GAS VENT OR LINER WILL PREVENT
DETERIORATION OF THE CHIMNEY DUE TO
THE EXCESSIVE CONDENSATION WHICH
RESULTS ON OVERSIZED SYSTEMS.

WARNING
UNDER NO CIRCUMSTANCES SHOULD THE FLUE PIPE BE CONNECTED TO THE CHIMNEY OF AN
OPEN FIREPLACE
.
TABLE 1.8.7A
WATER BOILER & STEAM BOILERS TO 50 PSIG
TABLE 1.8.7B
(STEAM BOILERS OVER 50 PSIG)
Diameter of
Connector, Inches
Minimum Thickness,
Inch (Gauge)
Diameter of
Connector, Inches
Minimum Thickness,
Inch (Gauge)
6 to 10 0.023 (24) 14 and less 0.053 (16)
10 to 12 0.029 (22) 14 to 16 0.067 (14)
12 to 16 0.034 (20) 16 to 18 0.093 (12)
16 + 0.056 (16) 18 + 0.123 (10)
1.8.8 VENT CONNECTORS (HORIZONTAL RUNS)
CONSTRUCTION
Vent connectors may be of any of the acceptable
constructions listed in this manual.
AVOID UNNECESSARY BENDS
The vent connector must be installed so as to
avoid turns or other construction features which
create excessive resistance to flow of flue gases.
JOINTS
Vent connectors must be firmly attached to draft
diverter outlets or boiler flue collars by sheet
metal screws or other approved means. Vent
connectors of Type B vent material must be
assembled in accordance with the vent
manufacturer's instructions. Joints between
sections of connector piping must be fastened
using sheet metal screws or other approved
means.
SLOPE OR VENT CONNECTOR
The vent connector must be installed without any
dips or sags and must slope upward at least 1/4
inch per foot.
LENGTH OF VENT CONNECTOR
The vent connector must be as short as possible
and the boiler close as practical to the chimney or
vent.
The horizontal run of an uninsulated vent
connector to a natural draft chimney or vent
servicing a single appliance must not be more
than 75% of the height of the chimney or vent
above the vent connector.
The horizontal run of an insulated vent connector
to a natural draft chimney or vent servicing a
single appliance must not exceed 100% of the
height of the chimney or vent above the vent
connector.
SUPPORT OF VENT CONNECTOR
The vent connector must be supported in
accordance with the vent manufacturer's
instructions and listing and with all applicable
codes. Support should also be independent of the
boiler or the draft diverter (when used). The vent
connector must be: supported for the design and
weight of the materials employed, maintain
clearances, prevent physical damage and
separation of joints, and to prevent sagging of the
vent connector.
Supports should usually be overhead hangers,
and of load bearing capacity appropriate for the
weight involved.
LOCATION
When the vent connector used for an appliance
having a draft hood must be located in or pass
though a crawl space or other area difficult to
access or which may be cold, that portion of the
vent connector must be of listed double wall Type
B gas vent material, or of material having
equivalent insulation qualities. Single wall metal

pipe used as a vent connector must not pass
through any floor or ceiling.
CHIMNEY CONNECTION
In entering a passageway in a masonry or metal
chimney, the vent connector must be installed
above the extreme bottom to avoid stoppage.
Means must be employed which will prevent the
vent connector from protruding so far as to
restrict the space between its end and the
opposite wall of the chimney. A thimble
or slip joint may be used to facilitate removal of
the vent connector. The vent connector must be
firmly attached to or inserted into the thimble or
slip joint to prevent the vent connector from falling
out.
DAMPERS
Manually operated dampers must not be placed
in the vent connector. This does not exclude the
use of fixed baffles, locking quadrant dampers
which are welded in a fixed position, or automatic
vent damper (when properly installed and
interlocked with the boiler gas controls).
USE OF THIMBLES
Vent connectors made of single wall metal pipe
must not pass though any combustible wall
unless they are guarded at the point of passage
by ventilated metal thimbles not smaller than the
following: 4" larger in diameter than the vent
connector, unless there is a run of not less than 6
feet of vent connector in the open, between draft
diverter outlet and the thimble, in which case the
thimble may be 2" larger. For unlisted appliances,
or for barometric provided with barometric
dampers, the thimble must be 6 inches larger in
diameter than the vent.
SINGLE WALL METAL VENT PIPE USED TO
VENT STEAM BOILERS OPERATING OVER 50
PSIG MUST NOT PASS THOUGH WALLS OR
PARTITIONS CONSTRUCTED OF
COMBUSTIBLE MATERIAL.
1.8.9 CHIMNEY & VENT CONSTRUCTION (VERTICAL SECTION)
INSTALLATION OF FACTORY BUILT SYSTEMS
Listed gas vents and factory built chimneys must be
installed in accordance with their listings and the
manufacturer's instructions. Vents and venting
systems passing through roofs must extend through
the roof flashing, roof thimble or roof jack.
INSTALLATION OF MASONRY OR METAL
CHIMNEYS
Masonry or metal chimneys must be built in
accordance with nationally recognized building codes
and standards.
INSTALLATION OF SINGLE WALL GAS VENTS
Single wall metal pipe may be used only for runs
directly from the space in which the appliance is
located through the roof or exterior wall to the outer
air. A pipe passing though a roof must extend without
interruption though the roof flashing, roof jack, or
thimble. Single wall metal pipe must not originate in
any unoccupied attic or concealed space. Additionally
it must not pass through any attic, inside wall,
concealed space or through any floor. Minimum
clearance must be maintained between the single wall
metal pipe and any combustible surface as outlined in
Table 1.8.9.

EQUIPMENT TYPE
MINIMUM REQUIRED DISTANCE FROM COMBUSTIBLE MATERIAL
Listed Type B Vent Single Wall Metal
Pipe
Factor Built Chimney
UL Listed F-Series Water or 15 psig
Steam with Draft Diverter as listed
6" as listed
UL Listed CL-Series Water or 15 psig
Steam with Draft Diverter or Barometric as listed
6" as listed
UL Listed K-Series Water with Draft
Diverter or Barometric
as listed 6" as listed
UL Listed K-Series 15 psig Steam with
Draft Diverter
as listed 6" as listed
UL Listed K-Series 15 psig Steam with
Barometric
not permitted 18" as listed
Unlisted Water and 15 psig Steam
Boilers
not permitted 18" as listed
All Steam Boilers over 15 psig
Regardless of Draft Control
not permitted 36" as listed
When a single wall metal pipe passes through an
exterior wall constructed of combustible material,
it must be guarded at the point of passage by a
ventilated thimble as described under "Use of
Thimbles" in Section 1.8.8 of this manual.
Alternatively, a non-ventilating thimble not less
than 18" above and 6" below the roof (with the
annular space open at the bottom and closed at
the top) may be used.
INSPECTIONS OF CHIMNEYS
Before connection of a vent connector to a
chimney, the chimney passageway must be
examined to ascertain that it is clear and free of
obstructions. Cleanouts must be constructed
such that they will remain tightly closed when not
in use. Tee fittings used as cleanouts or
condensate drains must have tight fitting caps to
prevent entrance of air into the chimney at such
points. When an existing masonry chimney is
unlined and local experience indicates that vent
gas condensate may be a problem, an approved
liner or another vent must be installed. When
inspection reveals that an existing chimney is not
safe for the intended application, it must be rebuilt
to conform to nationally recognized standards,
relined with a suitable liner, or replaced with a gas
vent or chimney suitable for the appliances to be
attached.
SUPPORT OF CHIMNEYS AND VENTS
All portions of chimneys must be adequately
supported for the design and weight of the
materials employed. Listed factory built chimneys
must be supported and spaced in accordance
with their listings and the chimney or gas vent
manufacturer's recommendation. THE GAS
VENT OR CHIMNEY MUST BE SUPPORTED
INDEPENDENTLY OF THE BOILER TOP OR
DRAFT DIVERTER.
1.8.10 MARKING OF GAS VENTS
In those localities where solid and liquid fuels are
used extensively, gas vents must be plainly and
permanently identified by a label reading:
"This gas vent is for appliances which burn gas
only. Do not connect to incinerators or solid or
liquid fuel burning appliances."

This label must be attached to the wall or ceiling
at a point near where the gas vent connector
enters the wall, ceiling or chimney.
The authority having jurisdiction must determine
whether their area constitutes such a locality.
1.8.11 VENTING MULTIPLE APPLIANCES ON A COMMON VENT
COMMON GAS VENT
When two or more openings (for vent connectors)
are provided in a chimney or gas vent, the
opening should be at different levels. They should
never be opposite one another.
When two vent connectors enter the same gas
vent or chimney, the smallest of the two should
enter at the highest position possible.
PRESSURIZED VENTS OR VENT
CONNECTORS
DO NOT CONNECT THE FLUE OF AN
APPLIANCE VENTED BY NATURAL DRAFT TO
A VENT SYSTEM WHICH OPERATES UNDER
A POSITIVE PRESSURE.
SOLID FUEL APPLIANCE VENTS
Gas appliances must not be vented to a vent or a
chimney which serves a solid fuel burning
appliance.
1.8.12 VENT AND CHIMNEY TERMINATIONS
HEIGHT ABOVE ROOF AND OBSTACLE
WATER BOILERS AND LOW PRESSURE
STEAM BOILERS: No less than 3 feet above the
roof and no less than 2 feet above any parapet or
obstacle closer than 10 feet from the vent outlet
(Reference NFPA 211).
HIGH PRESSURE (OVER 15 PSIG) STEAM
BOILERS: No less than 10 feet higher than any
portion of any building within a distance of 25 feet
from the vent (Reference NFPA 211).
MINIMUM HEIGHT ABOVE DRAFT CONTROL
Chimneys and gas vents must extend at least 5
feet above the highest connected draft diverter
outlet, barometric draft control or any appliance
flue outlet.
CLEARANCE FROM AIR INLETS
The vent or chimney must terminate no less than
3 feet above any forced air inlet within a distance
of 10 feet. It must terminate no less than 1 foot
above, or 4 feet below, or 4 feet horizontally from,
any door, window or gravity air inlet into a
building.
CLEARANCE FROM PUBLIC WALKWAYS
The vent exit of a mechanical draft system must
be at least 7 feet above grade when located next
to public walkways.
PROTECTION OF BUILDING MATERIALS
FROM POSSIBLE CORROSION OR
DISCOLORATION FROM FLUE PRODUCTS
The products of combustion from gas or oil
contain potentially corrosive gases and high
temperatures. For this reason, the chimney or
vent exit must be designed to prevent exposure
of the building materials to the flue products.
Failure to do so may result in deterioration or
discoloration of building materials.
VENT SUPPORT
The gas vent or chimney must be securely
positioned and supported. Guy wires or other
reliable means must be used to prevent
movement of the vent.
PROTECTION AGAINST BLOCKAGE OR
OBSTRUCTION
The chimney or vent exit design must prevent any
possibility of blockage by snow or by any other
obstruction.
FIG. 1.8.12B: LOW RESISTANCE STACK CAP

VENTILATING HOODS AND EXHAUST
SYSTEMS
Ventilating hoods or exhaust systems may be
used to vent atmospheric gas appliances. When
these are used, however, such mechanical
exhaust devices must be electrically interlocked
with all appliances on the vent system. The circuit
must prevent the operation of any appliance on
the system if the hood or exhaust system is not in
operation.
STACK CAPS
EVERY GAS VENT MUST BE SUPPLIED WITH
AN APPROVED VENT CAP WHICH WILL
PREVENT THE ENTRANCE OF RAIN OR
OTHER PRECIPITATION INTO THE VENT.
FAILURE TO PROVIDE SUCH A CAP MAY
CAUSE SEVERE BOILER CORROSION OR
COMBUSTION PROBLEMS OR BOTH.
Listed gas vents must be terminated with a listed
cap, approved for use with the particular gas
vent.
Listed vent caps or roof assemblies must have a
rated venting capacity no less than the vent.
Single wall vents must terminate in an approved
cap which does not obstruct the exit. The
preferred type of cap for natural draft vented
atmospheric boilers is the Briedert Cap. This is
because of the protection this cap provides
against wind generated downdrafts.
Where there is no concern of high winds or
turbulence at the vent exit, a low resistance
conical cap may be used. See Fig. 1.8.12B for
typical dimensions. The diameter of this type cap
should be twice the vent diameter. The cap must
be securely positioned on the vent such as to
provide a clearance of one vent diameter above
the vent exit.
1.8.13 AUTOMATIC VENT DAMPERS
ONE APPLIANCE ONLY
An automatic vent must be installed such that it
serves only one appliance vent - that to which is
properly interlocked.
LISTING REQUIREMENTS
Automatic vent dampers, if used, must be of a
listed type.
INSTALLATION
The damper installation must comply with
Appendix I, J, or K of the National Fuel Gas
Code, NFPA 54. The installation must also
comply with the automatic vent damper listing,
the damper manufacturer's instructions and all
applicable local or state building codes.
AUTOMATIC VENT DAMPERS MUST BE
INSTALLED ONLY BY QUALIFIED SERVICE
TECHNICIANS. FAILURE TO PROPERLY
INSTALL A VENT DAMPER WILL CREATE A
SEVERE HAZARD.
PERFORMANCE TEST
The damper must be tested after installation to
assure its proper and safe operation.
AUTOMATIC VENT DAMPERS MUST BE IN
THE OPEN POSITION AT ANY TIME THE
APPLIANCE MAIN GAS VALVE IS ENERGIZED.
1.8.14 SIZING OF CHIMNEY AND VENT
IMPORTANT
The flue system calculations which follow in
Section 1.8.15 are applicable to double-wall or
insulated single wall breechings (vent connectors)
and stacks (vents). Do not apply these
calculations to uninsulated vent systems.
HIGH ALTITUDES
At altitudes of 2000 feet and higher, atmospheric
boilers must be derated. The amount of derate
required by the National Fuel Gas Code is 4% per
1000 feet above sea level. Boilers which are
shipped from the factory prepared for these
altitudes have the gas orifices properly sized for
this derate. The altitude and gas Btu content for
which the boilers have been constructed is listed

on the Equipment List/Submittal Data in the boiler
manual. The boilers will also be provided with a
label indicating that they have been prepared for
high altitude. If a boiler is to be installed at an
altitude other than that for which it was factory
built, orifices must be replaced to properly adjust
the gas input. Consult the factory or the local
Bryan Representative for the proper parts. For
the purpose of vent system sizing, assume full
input and determine sizing as if at sea level. The
derate factor of 4% per 1000 feet above sea
level accounts for the increased volume per
Btu/hr of flue products at high altitude.
INDUCED DRAFT FANS
Occasionally, the characteristics of an installation
are such that a natural draft vent system will not
suffice. In such cases, induced draft may be
used. The vent system is then sized with an
available "pumping" action equal to the total
theoretical draft plus the static pressure capability
of the induced draft fan. This will result in a
smaller diameter vent than for a natural draft
system. Sizing of induced draft fans should be
done using the recommendations of the fan
manufacturer and the ASHRAE Handbook.
FIG. 1.8.14: SUGGESTED APPLIANCE VENTING PROCEDURE
MULTIPLE APPLIANCE INSTALLATIONS
Bryan recommends that boilers and other gas
appliances be individually vented when possible.
See figure 1.8.14A. Individual venting provides
better draft control and fuel efficiency, and is less
likely to cause condensation in the system. When
individual venting is not possible, boilers may be
vented to a common breeching (vent connector).
See Fig. 1.8.14B for recommended design of
such a system. Note that connections of
individual boiler or
appliance vents into the common breeching
should be done with 45 elbows and not by
"bullheading" directly into the vent connector at
90 angles. "Bullhead" connections generally
cause excessive turbulence and poor draft
conditions. On vent connectors serving multiple
appliances, the diameter of the piping should be
increased at each appliance's entrance so as to
provide a relatively constant flue gas velocity
through the vent system. Using a constant
diameter breeching will often result in poor draft
at the outermost appliances.

1.8.15 QUICK SELECTION FOR VENT SIZING CHARTS
GENERAL
These charts were generated using the
procedure described in Chapter 26 of the
ASHRAE Equipment Handbook (1979). The
results are consistent with those of the National
Fuel Gas Code.The responsibility for assurance
of such compliance is that of the system designer
and/or the system installer. All sizing and
installation must be checked against such local
requirements.
The sizing herein is applicable to vent systems
utilizing double wall listed Type B vent as well as
single wall insulated vent with insulation
equivalent to double wall insulating value.
This sizing procedure is not applicable to vent
systems utilizing single wall uninsulated vents or
vent connectors.
The sizing information given herein is intended as
a general recommendation only. Vent sizing and
installation must comply with local codes.
RECTANGULAR VENTS
Vent systems may be rectangular as well as
circular. Table 1.8.15F has been provided to give
the circular equivalent of a rectangular duct.
These equivalent values account for the higher
pressure drop per cross sectional area for
rectangular ducts.
STEP 1: EQUIVALENT INPUT - DRAFT
CONTROL FACTOR
Determine the boiler (system) Draft Control
Factor, F1, from Table 1.8.15A.
Determine the boiler (or total system) input in
MBH. This is done by dividing the boiler (or total
system) input in Btu/hr by 1000.
Multiply the total input times factor F1.
The equivalent input, I, (without altitude
correction) is then: I = MBH x F1eq. 15A
TABLE 1.8.15A: DRAFT CONTROL FACTOR
F1
Multiply factor times input in MBH
Boiler Type Factor, F1
Atmospheric with Draft Hood 1.000
Atmospheric with Barometric 0.741
Forced Draft Gas or Oil 0.602
STEP 2: EQUIVALENT INPUT - ALTITUDE
FACTOR
Determine the boiler (system) Altitude Correction
Factor, F2, from Table 1.8.15B.
Multiply the boiler (or total system) input times
factors, F2and F1for the equivalent input.
The altitude correction factor, F2for atmospheric
boilers is equal to 1, because their inputs are
already derated for altitude.
The equivalent input, I, with corrections for
altitude is: I = MBH x F1x F2eq. 15B

Table 1.8.15B ALTITUDE CORRECTION FACTOR, F2
(Multiple factor times sea level Input, MBH)
Altitude (ft) Factor, F2Altitude (ft) Factor, F2
0 to 1999
2000
2500
3000
3500
4000
4500
5000
5500
1.00
1.075
1.096
1.116
1.136
1.157
1.180
1.202
1.25
6000
6500
7000
7500
8000
8500
9000
10000
1.247
1.272
1.296
1.322
1.346
1.373
1.399
1.453
STEP 3: SELECT TRIAL DIAMETER
Determine the NET STACK HEIGHT for the vent.
(The net stack height is the vertical distance from
the top of the atmospheric boiler draft control to
the top of the stack. On forced draft boilers it is
the distance from the boiler flue connection to the
top of the stack.)
Find the vent of TRIAL STACK DIAMETER. Enter
Table 1.8.15C at the Net Stack Height column
equal to the system net stack height. Then
proceed down the column to the input which is
just larger than the Equivalent Input of the
system. Read the Trial Stack Diameter in the left
hand column.
NOTE: This is only a trial diameter. Proceed to
Step 4 to calculate the system k-factor to
determine the actual stack diameter required.
STEP 4: CALCULATE SYSTEM K-FACTOR
The system "k-factor" accounts for the pressure
drop through fittings and vent piping. It is
calculated by adding up the individual k-factors
for each of the fittings plus the k-factor for the
vent pipe(s).
From Table 1.8.15D find the k-factors for each of
the elbows, tee fittings, draft regulators, etc. in the
system. Then calculate the vent piping k-factor
from the formula:
k
piping = 0.4 x L/Deq. 15C
L = total length of piping in feet
D = diameter of piping in inches
Add all the k-factors together to determine the
total system k-factor:
k
total = kpiping + kfittings eq. 15D
NOTE: On multiple appliance systems, multiply
the k-factor times 1.5. This is required only on
atmospheric boiler vent systems, not on forced
draft systems.
Table 1.8.15D: Vent Fitting k-Factors
Vertical Draft Hood
Barometric Draft Control
1.50
0.50
Low Resistance Stack
Cap
0.50
Round Elbow, 90
Round Elbow, 45
0.75
0.30
Converging Exit Cone (D1/D2)4- 1
(D1 is larger than
D2)
Tee or 90 Breeching
Y Breeching
1.25
0.75
Tapered Reducer 1 - (D2/D1)4
(D1 is larger than
D2)

STEP 5: CORRECT EQUIVALENT INPUT FOR
SYSTEM K-FACTOR
The capacities listed in Table 1.8.15C are based
on a system k-factor equal to 7.5. For any other
k-factor, the vent capacity must be adjusted. This
is accomplished by adjusting the equivalent input
for the system using a k-factor correction factor,
designated F3.
Refer to Table 1.8.15E for the equivalent input
correction factor which applies to the k-factor
calculated in Step 4. This factor is designated as
F3.
Multiply the equivalent input calculated in Step 2
times factor F3from Table 1.8.15E. This step will
yield a new equivalent input, I:
I = MBH x F1x F2x F3eq. 15E
Using this adjusted equivalent input, check the
stack diameter by following Steps 2 thru 3 again.
If the stack diameter remains the same, the sizing
is complete. If not, redo Steps 4 thru 5 etc. until
an acceptable result is achieved.
Table 1.8.15E: K-Factor Equivalent Input Correction Factor F3
K- Factor F3K- Factor F3K- Factor F3K- Factor F3K- Factor F3
1.00 0.37
1.50 0.45
2.00 0.52
2.50 0.58
3.00 0.63
3.50 0.68
4.00 0.73
4.50 0.77
5.00 0.82
5.50 0.86
6.00 0.89
6.50 0.93
7.00 0.97
7.50 1.00
8.00 1.03
8.50 1.06
9.00 1.10
9.50 1.13
10.00 1.15
10.50 1.18
11.00 1.21
11.50 1.24
12.00 1.26
12.50 1.29
13.00 1.32
13.50 1.34
14.00 1.37
14.50 1.39
15.00 1.41
15.50 1.44
16.00 1.46
16.50 1.48
17.0 1.51
17.50 1.53
18.00 1.55
18.50 1.57
19.00 1.59
19.50 1.61
20.00 1.63
20.50 1.65
21.00 1.67
21.50 1.69
22.00 1.71
22.50 1.73
23.00 1.75