GWS GWS-063 Installation and operating instructions

Part Number 550-110-734/1108
Hazard definitions
Hazards that will cause severe personal injury,
death or substantial property damage.
Hazards that can cause severe personal injury,
death or substantial property damage.
Hazards that will or can cause minor personal
injury or property damage.
Special instructions on installation, operation or
maintenance that are important but not related to
personal injury or property damage.
Contents Page
1 Determine venting method........................................2
2 Combustion air supply...............................................3
3 Obtain vent system components...............................4
4 Install vent starter......................................................6
5 Vent termination........................................................7
6 Direct exhaust — Vertical and sidewall venting.........8
7 Direct vent — Sidewall venting................................10
8 Direct vent —Vertical venting.................................12
Venting Manual
GWS
Gas-Fired Water Boilers
(Also includes GWS-090E)
INSTALLER — Read all instructions before
installing. Follow all instructions in proper order
to prevent personal injury or death.
Boilermust beventedandsuppliedwith combus-
tion air as described in this manual.Failure to do
so will result in severe personal injury, death or
substantial property damage.
Use only the sealant specified by the vent pipe
manufacturer, applied per their instructions.Vent
piping must be sealed gas-tight to prevent pos-
sibility of flue gas spillage and carbon monoxide
emissions, resulting in severe personal injury or
death.
Provide combustion and ventilation air openings
as described in the GWS or GWS-090E Boiler
Manual. Failure to provide adequate air supply
could result in severe personal injury, death or
substantial property damage.
USER — Please read the following. Failure to
comply could result in severe personal injury,
death or substantial property damage.
• This manual is for use only by your qualified
heating installer/service technician.
• PleaseseetheUser’sInformationManualforyour
reference.
• We recommend regular service by a qualied
service technician, at least annually.
Venting method definitions
Direct vent — Uses outside combustion air with combustion air
connector piping sealed at all joints and seams. Also known as
“sealed combustion”.All GWS and GWS-090E flue gas vents are
pressurized, requiring careful sealing of all joints.
Direct exhaust venting — Uses inside combustion air with no
combustion air connector piping. All GWS flue gas vents are
pressurized, requiring careful sealing of all joints. Also known
as “non-direct venting”.(DO NOT apply direct exhaust venting to
GWS-090E boilers — they must be direct vented only.)
Chimney draft venting — Uses the natural draft provided by
a vertical vent or chimney. (This method cannot be used with
GWS boilers.)
Chimney draft venting cannot be used for GWS
or GWS-090E boilers. Vent system must be con-
structed only using venting materials listed in this
Venting Manual.Existing vertical vents or chimneys
may only be used as raceways for routing vent or
vent/air piping as described in thisVenting Manual.
ThisVentingManualmustonlybeusedbyaqualified
installer/servicetechnician.Readtheseinstructions
completelybeforebeginningtheinstallation.Failure
to follow all instructions in proper order can cause
severepersonalinjury,deathorsubstantialproperty
damage.
To install a new vent system follow instructions in:
 • ThisVentingManual
 • GWSorGWS-090EBoilerManual
 • Ventpipemanufacturer’sinstructionssupplied
with vent material.
DONOTapplydirectexhaustventingforGWS-090E
boilers.Theseboilersmustonlybeinstalledasdirect
vent.

GWS Gas-Fired Water Boilers – Venting Manual
2Part Number 550-110-734/1108
1 Determine venting method
To prevent potential of severe personal injury or death, check for areas and products listed inTable 1, page 3, before in-
stalling boiler. If found, either remove products permanently or provide outside combustion air (direct vent installation).
Direct exhaust venting
Use only when openings for inside combustion air can be sup-
plied in accordance with the GWS or GWS-090E Boiler Manual,
this venting manual and with all applicable codes.You must direct
vent the boiler if the boiler area may contain contaminants as
described in this manual. Two direct exhaust vent options are
permitted: sidewall and vertical, per instructions in this manual.
See Figure 1, items 1 and 2.
Install an elbow on the air intake fitting as shown
in illustrations in this Venting Manual.This will help
prevent accidental blockage of the air intake.
Do not apply to GWS-090E boilers. GWS-090E
boilers must be direct vented.
Figure 1 Venting methods
Direct venting
Combustionairis providedbyairpiping connecting fromtheboiler
air intake fitting to the outside.
You must direct vent the boiler (pipe outside air to boiler air
intake fitting) if the boiler area may contain contaminants as
described in this manual.
Two direct vent options are permitted:
1. Direct vent sidewall
— using Vent/Air Intake Termination Kit. See instructions in
this venting manual.Termination kit is included with GWS or
GWS-090E boiler. See Figure 1, item 3.
2. Direct vent vertical
—usingThrough-RooforThrough-Unused-ChimneyTermina-
tion Kit. See Figure 1, item 4.
All GWS-090E boilers must be direct vented (not
direct exhaust).
Do not apply direct exhaust to GWS-090E boilers.
GWS-090E boilers must be direct vented.

3
Part Number 550-110-734/1108
GWS Gas-Fired Water Boilers – Venting Manual
2 Combustion air supply
If the boiler is installed in any area likely to cause contamination, or if
products which would contaminate the air cannot be removed, you must
pipe combustion air to the boiler air intake.Contaminated combustion
air will damage the boiler, resulting in possible severe personal injury,
death or substantial property damage. Do not install a GWS boiler in a
laundry room or pool facility, for example, without using ducted outside
air.These areas will always contain contaminants.
Please review the following information on potential combustion air contamination
problems.
Refer to Table 1 for products and areas that may cause contaminated combustion air.
These contaminants may cause damage to the vent piping, and must be eliminated
from the boiler combustion air supply. You may do this by removing the contaminants
permanently from the area or piping air directly to the boiler (direct vent) using one of
the methods described in this manual.
Table 1 Corrosive contaminants
Products to avoid
Spray cans containing chloro/fluorocarbons
Permanent wave solutions
Chlorinated waxes/cleaners
Chlorine-based swimming pool chemicals
Calcium chloride used for thawing
Sodium chloride used for water softening
Refrigerant leaks
Paint or varnish removers
Hydrochloric acid/muriatic acid
Cements and glues
Antistatic fabric softeners used in clothes dryers
Chlorine-type bleaches, detergents, and cleaning solvents found in household laundry rooms
Adhesives used to fasten building products and other similar products
Areas likely to have contaminants
Dry cleaning/laundry areas and establishments
Swimming pools
Metal fabrication plants
Beauty shops
Refrigeration repair shops
Photo processing plants
Auto body shops
Plastic manufacturing plants
Furniture refinishing areas and establishments
New building construction
Remodeling areas
Garages with workshops

GWS Gas-Fired Water Boilers – Venting Manual
4Part Number 550-110-734/1108
Vent and air components
1. The following special gas vent systems comply with UL-1738
andULC-S636standardsandarecertifiedbyCSAastheonly
systems suitable for use with GWS and GWS-090E boilers.
Use only 3” vent piping from following:
 • Heat-Fab,Inc.Saf-TVent®
 • Flex-LInternational,Inc.StaR-34
 • Z-Flex®,Inc.Z-Vent II
 • ProTechSystemsFasNSeal™
Use only the vent starter of the same manufacturer
as the vent components. Do not mix components
from different systems.The vent system could fail,
causing flue gas spillage, resulting in severe per-
sonal injury or death.
2. Use suitable 3” material for combustion air connector piping,
such as:
 • Dryervent
 • Galvanizedsteel
 • PVC(3”I.D.)
Direct exhaust and Direct vent sidewall
1. Select vent method based on page 2 and installation require-
ments.
2. Refer toTable 2 for maximum vent run lengths and number of
elbows. Do not exceed data inTable 2.
3. Select vent components from separate GWI and GWS Vent
Component Supplement.Allcomponents,including thevent
starter, must be of the same vent manufacturer. Do not mix
components.
3 Obtain vent system components
Table 2 Direct exhaust and sidewall direct vent
maximum vent length
Maximum vent length
(feet) Total number of elbows (Notes 1– 3)
123456
GWS-063, -095 &
GWS-090E 55 48 41 34 27 20
GWS-127 & GWS-158 45 38 31 24 17 10
Notes:
1. Do not include termination fitting when counting total number of elbows.
2. One (1) 90° elbow equals two (2) 45° elbows.
3. GWs-090E can only be direct vented.

5
Part Number 550-110-734/1108
GWS Gas-Fired Water Boilers – Venting Manual
Figure 2 Vertical direct vent — Typical installation,
showing component identification
Figure 3 Vertical direct vent — Parts provided in
Through-Roof or Through-Unused-Chimney
Termination Kit (part number 382-200-436WT)
1 Tee, galvanized 5” x 5” x 3” — qty: 1
2 Vent clamp — qty: 5
3 Bottom cap, galvanized with 4½” hole — qty:1
4 Vent support — qty: 1
5 Elastomer grippers — qty: 11
6 Screws, sheet metal, type A, #10 x 1¼” — qty: 11
7 Screws, sheet metal, type A, #10 x ½” — qty: 3
8 Elastomer flashing — qty: 2
Table 3 Vertical direct vent — Parts
required but not provided in kit
(provided by installer, see Figure 2)
Description Quantity
Rain cap, galvanized, 5” 1
Adjustable flashing, type B, 5” 1
Fire stop for each floor or attic penetration 1
Storm ring, type B, 5” 1
Support, type B, 5” 1
Draft hood connector, type B, 5” 1
Adequate B-Vent with clamp rings for combustion air run
(less than 30 feet) --
Adequate 3” vent material for vent run and elbows from
one of the following (See Note):
• Heat-Fab,Inc.—Saf-TVent®
• ProTechSystems—FasNSeal™
• Flex-LInternational,Inc.—StaR-34
• Z-Flex®,Inc.—Z-VentII
--
Adequatesealantspeciedbyventpipemanufacturer’s
instructions --
Adequate 3” PVC, galvanized or dryer vent (for
combustion air supply piping between tee and boiler) --
Note: Do not mix types of vent material.CSA certification will be void.
3 Obtain vent system components continued
Direct vent vertical
1. The Through-Roof or Through-Unused-Chimney Termina-
tion Kit, part number 382-200-436WT, provides special parts
required to route 3-inch stainless vent pipe through 5-inch
B-vent.The space between the vents provides the passage
for combustion air. See Figure 3 for parts included with the
kit.
2. Verify that the vent termination will comply with the require-
mentslisted onpage 7.Thenverifythat the ventand air piping
will not exceed the length limits given in Section 8, page 12 of
this manual before locating boiler or floor/roof penetrations.
3. You will need to obtain stainless vent pipe and fittings, using
only the vent systems listed in separate GWI and GWSVent
Component Supplement.AlsoobtainB-ventpipeandfittings
for the vertical run and floor/roof penetrations (See Table 3).

GWS Gas-Fired Water Boilers – Venting Manual
6Part Number 550-110-734/1108
4 Install vent starter
Use only the vent starter of the same manufacturer
as the vent components. Do not mix components
from different systems.The vent system could fail,
causing flue gas spillage, resulting in severe per-
sonal injury or death.
1. Select a vent pipe manufacturer and obtain all vent compo-
nents needed, based on boiler location and venting method.
2. You must use the vent starter made by the vent pipe manu-
facturer.SeeGWI and GWSVent Component Supplement,
for part number of each component, listed by vent manufac-
turer.
3. Follow all applicable national, state, local or provincial codes
when venting the GWS boiler.
4. Connect vent starter to blower housing outlet as shown in
Figure 4, below.
a. Do not mix components from different vent manufacturers.
b. Maintain minimum 2” clearance from combustible materials to
vent pipe. (Exception: PVC air pipe can be no closer than 3/16”
from the vent pipe, as dictated by the dimensions of the vent
termination.)
c. Seal with sealant specified by vent pipe manufacturer, using 3/8”
bead(notrequiredforFasNSeal™).
d. Tighten strap at band clamp screw until strap is snug around
blower housing.
Figure 4 Vent starters

7
Part Number 550-110-734/1108
GWS Gas-Fired Water Boilers – Venting Manual
5 Vent termination
Follow instructions on this page when determining vent location to avoid possibility of severe personal injury, death or
substantial property damage.
1. Locatethe boilerand ventpenetrationthrough thewall(Direct
exhaust and Direct vent sidewall) or roof (Direct vent vertical)
so all requirements on this page and in Figure 5 will be met.
Alsofollowventmanufacturer’sinstructions.
2. Gases will form white plume in winter. Plume could obstruct
window view of nearby windows in multistory buildings.
3. Prevailing winds could cause freezing of condensate and
water/ice buildup on vent termination, building, plants or roof.
Ice buildup on vent termination can cause boiler shutdown
and building freeze-up.
4. Direct exhaust — Winds over 31 mph can cause nuisance
boiler shutdown if boiler is sidewall vented.This could result
in loss of heat to building, causing freeze-up.
5. Locate or guard vent termination to prevent condensate from
damaging exterior surfaces.
6. Locatethevent termination well away from trees, shrubs, and
decorative items.
7. Locate or guard vent to prevent accidental contact by people
or pets.
8. Do not terminate vent in window well, stairwell, alcove, court-
yard, or other recessed areas.
9. Do not wrap or insulate vent pipe or fittings.
10. Directexhaustand Directventsidewall:Donotterminate vent
above any door or window. Condensate can freeze, causing
ice formations.
11. Do not connect:
• Anyotherappliancetoventpipe.
• Multipleboilerstoacommonventpipe.
12. Canadian installations — See B149.1 or B149.2 Installation
Code.Terminate vent no less than 6 feet from another com-
bustion air inlet, 3 feet from any other building opening, and
3 feet from any gas service regulator.
13. See Figure 5, showing that the vent must terminate:
• morethan1foot(Directvent)or4feet(Directexhaust)belowor
to side of all doors or windows.
• morethan1footabovegradeoranticipatedsnowline.
• atleast7feetabovepublicwalkway
• 3feetaboveanyforcedairintakewithin10feet.
14. Vent must also terminate:
• atleast6feetawayfromadjacentwalls.
• nocloserthan5feetbelowroofoverhang.
• atleast4feethorizontally(andinnocaseaboveorbelowunless
a 4 foot horizontal distance is maintained) from electric meters,
gas meters, regulators, relief valves, and other equipment.
15. Site conditions may dictate greater clearances.
16. Direct exhaust and Direct vent sidewall — Do not extend ex-
posed vent pipe outside of building.Condensate could freeze
and block vent pipe.
Figure 5 Sidewall Direct Vent or Direct Exhaust Vent — Vent termination minimum clearances
A gas vent extending through an exterior wall shall not terminate adjacent to the wall or below building extensions such
as eaves, overhangs, balconies or decks. Failure to comply could result in severe personal injury, death or substantial
property damage.

GWS Gas-Fired Water Boilers – Venting Manual
8Part Number 550-110-734/1108
6 Direct exhaust — Vertical and sidewall venting
Installation guidelines
1. Do not mix types or manufacturers of vent materials.
2. Clean all jointsbeforesealing.Seeventmanufacturer’sin-
structions for cleaning and sealing joints. Use their specified
sealant. Do not use screws.
3. Install vent pipe with seams on top of vent horizontal runs.
Follow requirements on page 6 for vent termination.
4. Maintain minimum 2” clearance from combustible materials
to vent pipe.
5. Vertical venting—SeeFigure6.Followventmanufacturer’s
instructions for venting through roof (or unused chimney or
vent as raceway).
• Ventpipemustextendthroughroofashing,jacketorthimble.
• Ventmaypassthroughoor,insidewallorconcealedspacewhen
installedaccordingtoventmanufacturer’sinstructions.
• Ventmaypassthroughanunusedchimneyorventasaraceway
if allowed by vent manufacturer and installed per vent manufac-
turer’sinstructions.
Sidewall venting — See Figure 7, page 9.Vent must termi-
nate at least one foot above anticipated snowline.Vent must
be terminated only with:
• Teeorelbowwithintegralscreen.(Teemaybemountedeither
vertically or horizontally.)
• Elboworterminationcouplingwithscreen(notavailableforStaR-
34).
6. Sidewall venting —Donotseal ventpipeto insideor outside
plate.
7. Sidewall venting — If passing through noncombustible wall,
provide hole diameter large enough to insert the vent pipe.
8. Install horizontal drain tee as close as possible to boiler, in
first horizontal run. See Figure 6.
9. Do not exceed the maximum vent system length given in
Table 3 on page 4.
Condensate drain line — use only silicone tubing
rated for at least 400 °F for the first 18” of conden-
sate drain line, then other non-metallic tubing may
be used.Using any other material could cause flue
gasleakage,potentiallyresultinginseverepersonal
injury, death or substantial property damage.
On some installations, the condensate drain fitting
may be omitted, provided:
• Ventmanufacturershowsthisoptionintheirinstruc-
tions.
• Ventisslopedtowardterminationasshownindotted
lines in Figure 6.
• Theventisinstalledperboilermanufacturer’sand
ventmanufacturer’sinstructions.
Condensate drippage from such vents may accumulate on the
ground below.Consider traffic in the area to avoid hazard due to
ice accumulation.
Figure 6 Direct exhaust vertical or sidewall venting
Install an elbow on the air intake fitting as shown
in illustrations in this Venting Manual.This will help
prevent accidental blockage of the air intake.
Do not apply to GWS-090E boilers. GWS-090E boilers must be direct vented.

9
Part Number 550-110-734/1108
GWS Gas-Fired Water Boilers – Venting Manual
Figure 7 Direct exhaust sidewall venting termination
6 Direct exhaust — Vertical and sidewall venting cont.
Do not apply to GWS-090E boilers. GWS-090E boilers must be direct vented.

GWS Gas-Fired Water Boilers – Venting Manual
10 Part Number 550-110-734/1108
7 Direct vent — Sidewall venting
Installation guidelines
1. Install vent and air piping in accordance with the GWS or
GWS-090E Boiler Manual, this Venting Manual and with
all applicable national, state, provincial and local codes. In
Canada, see B149.1 or B149.2 Installation Code.
2. Do not mix types or manufacturers of vent materials.
3. Cleanalljointsbeforesealing.Seeventpipemanufacturer’s
instructionsforcleaningand sealingjoints.Usetheir specified
sealant. Do not use screws.
4. Install vent pipe with seams on top of vent horizontal runs.
Follow requirements on page 7 for vent termination.
5. Maintainminimum2”clearancefrom combustiblematerialsto
vent pipe.Exception: PVC air pipe can be no closer than 3/16”
from the vent pipe, as dictated by the dimensions of the vent
termination.
6. See Figure 8. Vent must terminate at least one foot above
anticipated snow line.
7. Install horizontal drain tee as close as possible to boiler, in
first horizontal run. See Figure 8.
8. Do not exceed the maximum length given inTable 3, page 4,
for either the vent pipe or the air pipe.
Install Vent/Air Intake Termination
Use this kit with wall thicknesses of 2 inches mini-
mum, 24 inches maximum.
1. Refer to Figure 9 on page 11 for installation details.
2. Remove the sidewall vent kit box from boiler. The kit should
include the following items:
 •ventterminationcap  •screws
 •aluminuminsideplate •spacers
 •stainlesssteeloutsideplate •lockwashers
 •anchorsformasonrywalls
3. Sidewallventingcanbeinstalledwithpipesside-by-sideoron
top of one another with vent pipe on top.Do not cover up vent
Figure 8 Direct vent sidewall venting termination
termination cap and outside plate with any exterior building
material, such as siding or wood.
4. Cuta5”x8½”rectangularroughopeningininsideandoutside
wallsforventpipeand,ifused,combustionairpipe.Usepaper
template provided with kit.
Sealant recommended by vent pipe manufacturer
must be used as indicated in their instructions.Vent
pipingmustbesealedgas-tighttopreventpossibility
offluegasspillageandcarbonmonoxideemissions,
resulting in severe personal injury or death.
 Followventmanufacturer’sinstructionsforsupport
of vent pipe.Do not support from termination kit.
From outside the building
5. Install outside plate.
6. Loosely install vent pipe (with vent pipe termination in place)
throughthe terminationcapand outsideplate.Donot connect
pipe or seal to plate.
From inside the building
7. Install spacers and sleeve (if passing through combustible
wall).
8. Install inside plate.If used, feed combustion air pipe through
inside and outside plates.
From outside the building
9. Use termination cap to position combustion air pipe against
stops on the inside of termination cap.
10. Seal outside plate to building. Seal around combustion air
pipe.
11. Install termination cap. Set ¼” to ¾” space between outside
plate and stop on vent pipe termination.
From inside the building
12. Seal around air intake pipe on inside plate.
13. Complete vent pipe run to vent starter at boiler.(See page 11
for air piping instructions.)
Condensate drain line
— use only silicone
tubing rated for at least 400 °F for the
first 18”of condensate drain line, then
other non-metallictubing may be used.
Using any other material could cause
flue gas leakage, potentially resulting
in severe personal injury, death or
substantial property damage.

11
Part Number 550-110-734/1108
GWS Gas-Fired Water Boilers – Venting Manual
Figure 9 Termination assembly
Install combustion air piping
1. Sealall combustionair pipingjointsand seams,using sealant
as below:
a. Dryer vent — A piece of 3” galvanized is required at each end
to adapt.Seal all pipe joints and seams between pipe and dryer
vent with approved silicone sealant (see NOTICE below).
b. Galvanized pipe — Seal all joints and seams using approved
silicone sealant (see NOTICE below).
c. PVC pipe — Seal all joints using PVC cement.
Exceptwhere notedotherwiseabove,seal airpiping
using either the sealant specified by the vent pipe
manufacturer for vent joints or one of the following
silicone sealants:
 • DowCorning700™or732™
 • GeneralElectric108or800
Support theairpiping in the same manneras speci-
fied for the vent pipe by the vent pipe manufacturer.
Do not support the air pipe from the sidewall termi-
nation.
Sidewall venting multiple GWS boilers
Do not connect multiple boilers to the same vent.
Failure to comply could result in severe personal
injury, death or substantial property damage.
1. Space terminations apart as shown in Figure 10, below.
Figure 10 Venting multiple GWS boilers
Sidewall direct-vented vent pipe must terminate with coupling as shown in Figure 9. Failure to do so could result in flue
gas recirculation, with the potential of severe personal injury or death.
If you remove the air piping from an existing direct-vented installation, to change to direct exhaust venting, you must
replace the termination coupling with a down-turned termination elbow with screen or a termination tee with screen as
shown in Figure 6, page 8 and Figure 7, page 9.Failure to do so could result in nuisance outages and loss of heat, with
potential substantial property damage.
7 Direct vent — Sidewall venting continued

GWS Gas-Fired Water Boilers – Venting Manual
12 Part Number 550-110-734/1108
8 Direct vent — Vertical venting
Installation guidelines
1. Codes —Install ventand combustionair pipingincompliance
with all applicable national, state, local or provincial codes.
2. Do not connect:
• Anyotherappliancetocombustionairorventpiping.
• Anyotherapplianceintoorthroughchimneywhenusingexisting
chimney as raceway.
• Multipleboilersintocommonvent.
3. Vent length limits — Position boiler as close as possible to
vertical vent/air run. Do not exceed vent length limits given
in Section 8 of this manual. B-vent limit is 30 feet.Vent or air
maximum lengths are:
• GWS-063,GWS-095&GWS-090E:Max55equivalentfeet
• GWS-127&GWS-158:Max45equivalentfeet
4. Materials and construction —
• SealallB-ventcombustionairjointswithapprovedsiliconeseal-
ant(DowCorning700™or732™,GeneralElectric108or800,
or sealant specified by vent pipe manufacturer.B-vent sections
must be straight — no elbows.
• Constructventjointsperventmanufacturer’sinstructions,includ-
ing use of their specified sealant.Vent pipe routed inside B-vent
must also be fitted with vent clamps with elastomer grippers,
installed per “Installation — Assembly”, pages 14 and 15 of this
manual.
• Use only one of the approved vent systems listed inTable 2,
page 4. Do not mix types of vent material. CSA certification will
be void.
5. Install boiler per GWS or GWS-090E Boiler Manual.
Verify vent system length
The vent or air piping must be no longer than the maximum value
given in Tables 4 and 5. Note in the tables that the maximum
length of connector piping (vent or air piping between boiler and
B-vent tee connection) depends on the number of elbows and
the length of the B-vent section.The reason is each 90-degree
vent or air pipe elbow cause the same pressure drop as 7 feet
of straight pipe.
Vent/air piping length verification procedure:
Step 1 — Determine dimensions of vent/air pipe needed
for planned location
Measure or calculate the vent/air pipe lengths required for the
planned location of the boiler and floor/roof penetrations. See
Figure 11 for a typical layout.
• HowlongwilltheverticalB-ventsectionhavetobe?Round
up to the nearest 5 feet (for example, if B-vent length needs to
be 12 feet, round this amount up to the nearest 5 feet — use
15 feet for your B-vent length).(This is dimension Lin Figure
11.)
• Howmanyelbowswillbeneededintheventconnectorpiping
(fromboilertoB-venttee)?
• Howmanyfeetofventpipingwillbeneededfortheconnec-
tor runs? (This would be the sum of dimensions C & Din
Figure 11.)
• Howmanyelbowswillbeneededintheairconnectorpiping
(fromboilertoB-venttee)?
• Howmanyfeetofairpipingwillbeneededfortheconnector
runs?(ThiswouldbethesumofdimensionsA&Bin Fig-
ure 11.)
Step 2 — Verify that vent connector piping is within al-
lowable limits
UseTable 4 or 5, depending on boiler model to be used.Find the
row with the B-vent length the installation requires.Move across
to the column with the number of vent elbows needed for the in-
stallation.This number is the maximum allowable vent connector
piping length.
Step 3 — Verify that air connector piping is within al-
lowable limits
Use Table 4 or 5 on page 13, depending on boiler model to be
used.Find the row with the B-vent length the installation requires.
Move across to the column with the number of air pipe elbows
neededforthe installation.Thisnumber is themaximum allowable
air pipe connector piping length.
Step 4 — Replan boiler location & piping if piping length
of vent or air is too long
See if boiler can be moved closer to vertical vent/air piping.
See if you can reduce the number of elbows required vent piping
musthave2elbowsminimumin order to providehorizontalpiping
to install condensate drain tee.
Vertical venting multiple GWS boilers
1. MultipleGWSboilers maybe ventedwith ventterminations at
the same height.Space terminations to provide a minimum of
1footbetweenpipes forU.S.installations.ForCanadian instal-
lations, provide clearances required by B149.1 and B149.2
Installation Code.Refer to Figure 10 on page 11.

13
Part Number 550-110-734/1108
GWS Gas-Fired Water Boilers – Venting Manual
Example verification (Figure 11):
Step 1 — Vent/air piping required per plan
As an example, consider an installation of a GWS-127 boiler, where the boiler and vent/
air locations would require:
• Boilermodel=GWS-127.
• B-ventlength(L)=20 feet.
• Ventconnectorpipingrequires2 elbows.
• Ventconnectorpipinglength(D + C)=16 feet.
• Airconnectorpipingrequires1 elbow.
• Airconnectorpipinglength(B + A)=17 feet.
Step 2 — Verify vent piping
• EnterTable5attherowforB-ventlengthof20feet.
• Movetothe2-elbowcolumn.
• Readamaximum connector pipe length of 18 feet.
Conclusion — Vent piping is within limits because vent connector piping would only
be 16 feet (less than the maximum of 18 feet).
Step 3 — Verify air piping
• EnterTable5attherowforB-ventlengthof20feet.
• Movetothe1-elbowcolumn.
• Readamaximum connector pipe length of 25 feet.
Conclusion — Air piping is within limits because air connector piping would only be
17 feet (less than the maximum of 25 feet).
Step 4 — Replanning
No replanning needed.Vent and air piping lengths are within limits.
Table 4 GWS-063, -095 & GWS-
090E Maximum connector
pipe length, vent or air:
GWS-063, GWS-095 & GWS-090E
“B-Vent”
length
(feet)
L
Total number of elbows
1234567
Max. length from boiler to
“B-Vent”
5 43 36 29 22 15 8 1
10 38 31 24 17 10 3 --
15 33 26 19 12 5 -- --
20 28 21 14 7 -- -- --
25 23 16 9 2 -- -- --
30 18 11 4 -- -- -- --
Note: Combustion air connector
pipe length = A + B
Vent connector pipe length = C + D
Figure 11 Typical vent/air piping
Table 5 GWS-127 and GWS-158
Maximum connector pipe
length, vent or air:
GWS-127 and GWS-158
“B-Vent”
length
(feet)
L
Total number of elbows
1234567
Max. length from boiler to
“B-Vent”
5 33 26 19 12 5 -- --
10 28 21 14 7 -- -- --
15 23 16 9 2 -- -- --
20 18 11 4 -- -- -- --
25 13 6 -- -- -- -- --
30 8 1 -- -- -- -- --
Note: Combustion air connector
pipe length = A + B
Vent connector pipe length = C + D
8 Direct vent — Vertical venting continued

GWS Gas-Fired Water Boilers – Venting Manual
14 Part Number 550-110-734/1108
Installation — Assembly
Step 2 — Prepare and insert
vertical vent
1. From top or bottom of combustion air
run, install vent piping.
• Topofventpipingmustextend3”above
top of rain cap.See Figure 2, page 5.
• Bottomofventpipingmustextend18”
below draft hood connector.
2. At each vent joint:
a. Follow vent pipe manufacturer’s in-
structions to assemble and seal joints.
Sealant recommended by vent pipe
manufacturer must be used as indi-
cated in their instructions.
b. Apply 2 self-adhesive elastomer grip-
pers to vent clamp. Grippers must be
positionedonclampasshown inFigure
13. Bend out 2 ears on vent clamp.
c. Fasten clamp around vent pipe with 2
– 11/4” screws in top and bottom holes,
about every 5 feet. See Figure 14.
Tighten screws until clamp does not
turn or slide around vent piping.
Figure 14 Install vent clamps on
vent piping
Step 3 — Install vent support
1. Apply 1 elastomer gripper to vent sup-
port.
2. Install vent support around vent pip-
ing just below draft hood connector
as shown in Figure 15. Fasten sup-
port around vent piping with 1 – 11/4”
screw.
3. Tighten screw until support does not
turn or slide around vent piping.
Figure 15 Install vent support
Step 1 — Assemble B-vent pip-
ing
1. Install 5” type B support, B-vent com-
bustion air run, flashing, fire stops and
stormcollarpermanufacturer’sinstruc-
tions.Apply approved sealant to each
B-vent joint.See Figure 12.
2. Install type B draft hood connector to
bottomofcombustionairrun.Sealwith
approved sealant.
8 Direct vent — Vertical venting continued
Figure 12 Sealing B-vent joints
87305
Figure 13 Apply elastomer strips to
vent clamps
87306

15
Part Number 550-110-734/1108
GWS Gas-Fired Water Boilers – Venting Manual
Installation — Assembly continued
 Followventpipemanufacturer’sinstructionstoassembleandsealjoints.Sealantrecommendedbyventpipemanufac-
turer must be used as indicated in their instructions.Vent and combustion air connector piping must be sealed gas-tight
to prevent possibility of flue gas spillage and carbon monoxide emissions, resulting in severe personal injury or death.
Step 6 — Finish installation
1. Completeventpipingtoboiler,makingsuretofollowventpipemanufacturer’sinstructionsandventmanufacturer’sspecialgas
vent system vent and combustion air venting supplements.
2. Use any of the following to install combustion air connector piping from tee to boiler, making sure to seal all joints and seams:
a. 3” Flexible dryer vent — A piece of 3”galvanized is required at each end to adapt.Seal all pipe joints and seams between pipe and dryer vent
with approved sealant.
b. Galvanized or aluminum single wall pipe — Seal all joints and seams using approved sealant.
c. 3” PVC — Seal all joints using PVC cement.
3. Condensate drain line—Acondensatedrainttingisalwaysrequiredforthrough-roofvents.Followventmanufacturer’sinstruc-
tions to install condensate drain line.
Use only silicone tubing rated for at least 400 °F for the condensate drain line.Using any other material could cause flue
gas leakage, potentially resulting in severe personal injury, death or substantial property damage.
Figure 16 Install tee
Step 4 — Install 5”x 5”x 3” tee
1. Slideteeoverventpipingandattachuncrimpedend tobottom
of draft hood connector:
a. Drill 3 holes in tee for 1/4” sheet metal screws.
Do not allow drill to penetrate vent pipe.Drill holes
carefully in tee and use only 1
/4” screws to fasten
tee to draft hood connector. Failure to do so can
damage vent pipe, causing severe personal injury
or substantial property damage.
b. Seal all seams and screws with approved sealant.
2. Secure bottom cap to tee with duct tape. Slide elastomer
ashinguparoundventpipeandtucklipintocap’sbottom
opening. Seal with approved sealant.
Step 5 — Install rain cap
1. On roof, cut 4 1/2” hole in top of rain cap and install cap over
protruding vent pipe. Slide elastomer flashing down around
ventpipeandtucklipintocap’stopopening.
2. Connect termination coupling to vent pipe using vent pipe
manufacturer’sspeciedsealant.
Figure 17 Install rain cap
8 Direct vent — Vertical venting continued

GWS Gas-Fired Water Boilers – Venting Manual
16 Part Number 550-110-734/1108
W-T
8201 W. Calumet Rd.
Milwaukee, WI 53223