A.O. Smith 2100, 200, 201, 1000, 1500 User Manual

COPPER BOILERS FOR

HYDRONIC HEATING AND

HOT WATER SUPPLY

• Installation

• Operation

• Maintenance

Instruction Manual

GB/GW MODELS:

1000, 1300, 1500, 1850, 2100, 2500

• Limited Warranty

WARNING: If the information in this
manual is not followed exactly , a fire or
explosion may result causing property
damage, personal injury or loss of life.

Do not store or use gasoline or other

•

flammable vapors and liquids in the
vicinity of this or any other appliance.

WHAT TO DO IF YOU SMELL GAS:

• Extinguish any open flame.

• Do not try to light any appliance.

• Do not touch any electrical switch; do

not use any phone in your building.

• Immediately call your gas supplier

from a neighbor's phone. Follow the
gas supplier's instructions.

• If you cannot reach your gas supplier,

call the fire department.

Installation and service must be

•

performed by a qualified installer,
service agency or the gas supplier.

SERIES 200, 201

CAUTION

TEXT PRINTED OR OUTLINED IN RED CONTAINS
INFORMATION RELATIVE TO YOUR SAFETY.
PLEASE READ THOROUGHLY BEFORE INSTALLING
AND USING THIS APPLIANCE.

Thank You

A. O. Smith Water Products Co.

You should thoroughly read and understand this
manual before installation and/or operation of this
boiler. Please pay particular attention to the
important safety and operating instructions as well

as the WARNINGS and CAUTIONS.

CONTENTS P A G E

ROUGH-IN DIMENSIONS/CAPACITIES............. 2 - 3

FOREWORD .....................................................4 - 5

FEATURES/CONTROLS................................... 5 - 6

INSTALLA TION INSTRUCTIONS ................... 6 - 22

VENTING ....................................................... 8 - 14

SYSTEM INSTALLA TION ..............................15 - 19

HYDRONIC INST ALLATION ..........................15 - 17

HOT WA TER SUPPL Y INST ALLA TION ......... 17 - 19

GAS CONNECTIONS ....................................20 - 21

OPERATION ................................................ 22 - 23

LIGHTING AND OPERATING ......................... 24 - 25

CONTROL SYSTEM .................................... 26 - 31

PREVENTA TIVE MAINTENANCE ................ 31 - 33

TROUBLE SHOOTING ..................................33 - 34

LIMITED WARRANTY ..........................................35

WIRING DIAGRAM/SCHEMATIC .................. 36 - 37

for buying this cost

efficient, high recovery unit from

PLACE THESE INSTRUCTIONS ADJACENT TO BOILER AND

NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE.

PRINTED IN U.S.A. 2526 0501

A DIVISION OF A. O. SMITH CORPORA TION

EL P ASO, TX., MC BEE, SC., RENTON, W A.,

STRATFORD-ONT ARIO, VELDHOVEN-THE NETHERLANDS

www.hotwater.com

1

PART NO. 211257-000 REV . 0

ROUGH-IN DIMENSIONS

TOP VIEW

FRONT VIEW

IMPORT ANT!

Refer to "Installation Clearances" section of manual
(page 7) for recommended service clearances prior
to boiler placement.

LEFT SIDE

REAR VIEW

TABLE 1: GAS AND ELECTRICAL CHARACTERISTICS

Manifold Pressure Electrical Characteristics

Model Type of Gas Inches W.C. kPa Volts/Hz Amperes

GW/GB-1000

thru 2500 NATURAL 3.5 0.87 120/60 30

GW/GB-1000

thru 2500 PROPANE 10 2.49 120/60 30

All Models - Maximum Supply Pressure: 14.0 In. W.C. (3.49 kPa)
Minimum Supply Pressure Natural Gas: 6.0 In. W.C. (1.22 kPa)
Minimum Supply Pressure Propane Gas: 1 1.0 In. W.C. (2.74 kPa)
Minimum Pressures must be maintained under both load and no load
(static and dynamic) conditions.

Figure 1.

T ABLE 2. ROUGH - IN DIMENSIONS

ABCD EF

Model Inches c m Inches c m Inches cm Inches c m Inches cm Inches cm

GW/GB-1000 14.1 35.8 12.2 31.0 40.3 102.4 31.6 80.3 26.0 66.0 46.8 118.9
GW/GB-1300 24.8 63.0 12.2 31.0 40.3 102.4 31.6 80.3 39.3 99.8 57.3 145.5
GW/GB-1500 30.2 76.7 12.2 31.0 40.3 102.4 31.6 80.3 44.6 113.3 64.3 163.3
GW/GB-1850 27.7 70.4 11.2 28.4 43.0 109.2 32.3 82.0 44.0 111.8 78.3 198.9
GW/GB-2100 31.0 78.7 11.2 28.4 43.0 109.2 32.3 82.0 49.5 125.7 85.3 216.7
GW/GB-2500 38.1 96.8 10.5 26.7 43.0 109.2 32.3 82.0 56.5 143.5 99.3 252.2

Input Exhaust Inlet

Model Natural Gas Natural Gas Propane Gas Propane Gas Inches cm Inches cm Size

GW/GB-1000 990,000 289.95 990,000 289.95 10 25.4 8 20.3 2 1/2 NPT 2 NPT
GW/GB-1300 1,300,000 380.74 1,300,000 380.74 12 30.5 10 25.4 2 1/2 NPT 2 NPT
GW/GB-1500 1,500,000 439.31 1,500,000 439.31 12 30.5 10 25.4 2 1/2 NPT 2 NPT
GW/GB-1850 1,850,000 541.82 1,850,000 541.82 14 35.6 10 25.4 2 1/2 NPT 2 1/2 NPT
GW/GB-2100 2,100,000 615.04 2,100,000 615.04 14 35.6 12 30.5 2 1/2 NPT 2 1/2 NPT
GW/GB-2500 2,490,000 729.26 2,490,000 729.26 16 40.7 12 30.5 2 1/2 NPT 2 1/2 NPT

BTU/Hr. KW BTU/Hr. KW Vent Diameter Vent Diameter Water Conn. Gas Inlet

2

TABLE 3: RECOVERY CAP ACITIES

T emperature Rise - Degrees °F (°C)

Input Rating Gal/Liter 40°F 50°F 60°F 70°F 80°F 90°F 100°F 110°F 120°F 130°F

MODEL BTU/Hr. (kW) per Hr. (22.2°) (27.7°) (33.3°) (38.8°) (44.4°) (50°) (55.5°) (61.1°) (66.7°) (72.2°)
GW - 1000 990,000 (290.1) LPH 9526 7620 6350 5443 4763 4234 3810 3462 3175 2930

GPH 2520 2016 1680 1440 1260 1120 1008 916 840 775

GW - 1300 1,300,000 (380.9) LPH 12508 10006 8339 7148 6256 5560 5005 4547 4169 3848

GPH 3309 2647 2206 1891 1655 1471 1324 1203 1103 1018

GW - 1500 1,500,000 (439.5) LPH 14432 11548 9620 8248 7216 6415 5772 5247 4812 4442

GPH 3818 3055 2545 2182 1909 1697 1527 1388 1273 1175

GW - 1850 1,850,000 (542.0) LPH 17800 14239 11865 10172 8902 7912 7122 6471 5935 5477

GPH 4709 3767 3139 2691 2355 2093 1884 1712 1570 1449

GW - 2100 2,100,000 (615.3) LPH 20204 16163 13472 11548 10104 8981 8082 7348 6736 6218

GPH 5345 4276 3564 3055 2673 2376 2138 1944 1782 1645

GW - 2500 2,490,000 (729.6) LPH 23958 19168 15971 13691 11979 10648 9582 8713 7987 7371

GPH 6338 5071 4225 3622 3169 2817 2535 2305 2113 1950

TABLE 4: HEA T EXCHANGER PRESSURE DROP

GB Models-Flow, Head Loss and Temperature Rise

20 Deg. F Rise 30 Deg. F Rise 40 Deg. F Rise Maximum Flow Rate Minimum Flow Rate

GPM PD-FT GPM PD-FT GPM PD-FT GPM PD-FT Deg. F GPM PD-FT Deg. F

MODEL Head Head Head Head Rise Head Rise
GB - 1000 83.16 5.1 55.4 2.7 41.6 1.5 1 5 4 12.2 11 4 2 1.5 40

GB - 1300 109.2 7.2 72.8 4.2 54.6 3.2 1 5 4 14.5 1 4 55 3.2 40

GB - 1500 126 10.1 84 6.3 63 4.3 154 16.3 17 64 4.3 40

GB - 1850 154 18.5 103.6 10.1 77.7 6.4 1 5 4 18.5 2 0 78 6.4 4 0

GB - 2100 n/a n/a 117.6 14.5 88.2 8.3 154 21.3 23 8 9 8.3 40

GB - 2500 n/a n/a 139.4 18.5 104.6 11.6 154 23.2 2 8 105 11.6 4 0

Note: GW models (GB optional) are equipped with pumps capable of handling 50 equivalent feet

(15.2 m) of normal pipe fittings.

3

FOREWORD

PRECAUTIONS

These designs comply with the latest edition of the American
National Standards for Gas-Fired, Low-Pressure Steam and Hot
Water Boilers, ANSI Z21.13 and CGA 4.9/CGA 3.3 latest edition, as
a low pressure boiler.

Detailed installation diagrams are found in this manual. These
diagrams will serve to provide the installer a reference for the
materials and methods of piping necessary. It is essential that all
water, gas piping and wiring be inst alled as shown on the diagrams.
You should thoroughly read and understand this manual before
installation and/or operation of this boiler.

The factory warranty will be
installed or operated.

In addition to these instructions, the boiler(s) shall be installed in
accordance with those installation regulations in force in the local
area where the installation is to be made. These shall be carefully
followed in all cases. Authorities having jurisdiction should be
consulted before installations are made.

In the absence of local codes, the installation must comply with
the latest editions.

In the United States:
The National Fuel Gas Code, ANSI Z223.1/NFP A 54 and the National
Electric Code, NFPA 70.

In Canada:
The installation Code CAN/CSA B149.1 and .2 (latest edition) and
the Canadian Electric Code, CSA C22.2.

These are available from the Canadian Standards Association,
8501 East Pleasant Valley Road, Cleveland, OH 44131, USA, or,
Canadian Gas Association Laboratories, 55 Scarsdale Road, Don
Mills, Ontario M3B 2R3, Canada.

void if the boiler(s) have been improperly

GROUNDING INSTRUCTIONS

IF THE UNIT IS EXPOSED TO THE FOLLOWING, DO NOT
OPERATE UNTIL ALL CORRECTIVE STEPS HAVE BEEN MADE
BY A QUALIFIED SERVICEMAN:

1. EXPOSURE TO FIRE.

2. IF DAMAGED.

3. FIRING WITHOUT WA TER.

4. SOOTING.

IF THE BOILER HAS BEEN EXPOSED TO FLOODING, IT MUST BE
REPLACED.

LIQUID PETROLEUM MODELS

Boilers for propane or liquefied petroleum gas (LPG) are different
from natural gas models. A natural gas boiler will not function
safely on LP gas and no attempt should be made to convert a
boiler from natural gas to LP gas.

LP gas must be used with great caution. It is highly explosive and
heavier than air. It collects first in the low areas making its odor
difficult to detect at nose level. If LP gas is present or even
suspected, do not attempt to find the cause yourself. Leave the
building, leaving doors open to ventilate, then call your gas supplier
or service agent. Keep area clear until a service call has been
made.

At times you may not be able to smell an LP gas leak. One cause
is odor fade, which is a loss of the chemical odorant that gives LP
gas its distinctive smell. Another cause can be your physical
condition, such as having a cold or diminishing sense of smell
with age. For these reasons, the use of a propane gas detector is
recommended.

IF YOU EXPERIENCE AN OUT OF GAS SITUA TION, DO NOT TRY
TO RELIGHT APPLIANCES YOURSELF. Call your local service
agent. Only trained LP professionals should conduct the required
safety checks in accordance with industry standards.

This boiler must be grounded in accordance with the National
Electrical Code and/or local codes. Boiler is polarity sensitive,
correct wiring is imperative for proper operation.

This boiler must be connected to a grounded metal, permanent
wiring system, or an equipment grounding conductor must be run
with the circuit conductors and connected to the equipment
grounding terminal or lead on the boiler.

WARNING

YOUR BOILER IS NOT DESIGNED TO OPERA TE WITH A BOILER
INLET WATER TEMPERATURE OF LESS THAN 120°F (38°C).
COLDER INLET WATER TEMPERATURE WILL RESULT IN
SIGNIFICANT CONDENSATION DEVELOPING ON THE HEAT
EXCHANGER. THIS SITUATION CAN CAUSE A CORROSIVE
ENVIRONMENT FOR THE HEAT EXCHANGER, BURNERS AND
VENTING RESULTING IN PREMA TURE DAMAGE, WHICH COULD
RESUL T IN SERIOUS PERSONAL INJUR Y OR DEATH.

FOR SYSTEMS THAT USE LARGE VOLUMES OF COLD WATER
OR SYSTEMS UTILIZING HEA VY WA TER DRAWS, CONDENSA TION
CAN BE PREVENTED BY USING A BYP ASS LOOP.

CORRECT GAS

Make sure the gas on which the boiler will operate is the same as
that specified on the boiler rating plate. Do not install the boiler if
equipped for a different type of gas, consult your gas supplier.

HIGH AL TITUDE INST ALLATION

WARNING

INSTALLATIONS ABOVE 4,500 FEET REQUIRE REPLACEMENT
OF THE BURNER ORIFICES IN ACCORDANCE WITH THE
NATIONAL FUEL GAS CODE (ANSI/NFPA 54). FAILURE TO
REPLACE THE ORIFICES WILL RESULT IN IMPROPER AND
INEFFICIENT OPERATION OF THE APPLIANCE, PRODUCING
CARBON MONOXIDE GAS IN EXCESS OF SAFE LIMITS, WHICH
COULD RESULT IN SERIOUS PERSONAL INJURY OR DEATH.

GENESIS BOILERS ARE EQUIPPED WITH SELF-REGULATING
PREJET ORIFICES WHICH AUT OMATICALL Y COMPENSATE FOR
HIGHER ELEVATIONS AND ADJUST THE APPLIANCE'S INPUT
RA TE ACCORDINGL Y, MAKING IT UNNECESSARY TO REPLACE
ORIFICES FOR HIGH ALTITUDE (UP TO 4,500 FEET ONLY.
CONSULT THE F ACTORY FOR HIGHER AL TITUDES.)

Some utility companies derate their gas for altitude. You should
contact your gas supplier for any specific changes which may be
required in your area. Call the local gas utility to verify BTU content
of the gas supplied.

Ratings specified by manufacturers for most boilers apply for
elevations up to 4,500 feet (1350 m). For elevations above 4,500
feet (1350 m) ratings must be reduced by a rate of 4% for each
1,000 feet (300 m) above sea level.

4

Example: A Genesis boiler is rated at 1,300,000 Btu/hr. input at sea
level. At an altitude of 5,000 (1500m), the prejet orifices will decrease
the input rate by 20% (= 4% x 5) to a new rating of 1,040,000 Btu/hr.
(= 80% x 1,300,000 Btu/hr.) The input reduction is achieved by the
prejet orifices through self-regulation.

FEATURES/CONTROLS

FLAME SENSOR

The flame sensor acts to prove the flame has carried over from the
ignitor to the right-most burner. If no flame is sensed, the gas
valve(s) will close automatically. If no flame is sensed on three
ignition trials the boiler will lock out. Upon lockout, manually push
the ENTER/RESET button on the display panel to rest art the boiler.

MUL TI-STAGE FIRING AND CONTROL SYSTEM

ALL MODELS - The control system consists of three basic
components: 1) Central Control Board 2) Ignition Control Board
and 3) Display Board. The Central Control Board and Ignition
Control Boards are located in the control box and can be accessed
through panels on the left side and top of the unit. The Display
Board is attached to the front jacket panel. The control system is a
multi-stage control capable of managing three or four ignition
stages. Three stage models include the 1000, 1300 and 1500.
Four stage models include the 1850, 2100 and 2500. Every system
will have one Central Control Board, one Display Board and either
three or four Ignition Control Boards depending on the model.
There will be one Ignition Control Board per stage.

The central control board contains a strip of dip switches which
allow the user to control several system variables. Table 5 shows
a summary of these options. Make sure the dip switches are in
the appropriate position for the unit's application. Consult the
Control System section of the manual for more information, see
page 26.

DIP SWITCH CONFIGURA TION T ABLE

SW 1 OFF ON SELECTION:

A 3 STAGE 4 STAGE EITHER 3 OR 4 STAGE SYSTEM
B 3 TRIALS 1 TRIAL EITHER 3 OR 1
C NO IRI IR I WHETHER SYSTEM IS IRI OR

GAS VALVE GAS VALVE STANDARD

D INLET T ANK INLET OR T ANK AS

CONTROLLING PROBE

E NO EXTERNAL EXTERNAL WHETHER EXTERNAL

THERMOSTAT THERMOSTAT THERMOSTA T IS USED

F OUTLET 210°F OUTLET 240°F OUTLET MAXIMUM TEMPERA TURE
G 190°F 220°F MAX. SET-POINT TEMPERA TURE
H DEGREES °F DEGREES °C EITHER °F OR °C FOR DISPLAYED

TEMPERA TURE

WA TER FLOW SWITCH

The Water Flow Switch is installed at the boiler outlet to prevent
burner operation in the event of inadequate water flow through the
boiler. The Water Flow Switch is a single pole, normally open
switch that will close its contacts when increasing water flow rate
is encountered. This switch is factory-set, but may require field
adjustment. The contacts will open when the flow rate drops below
the adjusted setting and the gas valve(s) will close turning off the
gas to the burners.

LIMIT CONTROLS

CAUTION

LIMIT CONTROLS ARE SAFETY DEVICES AND ARE NOT TO BE
USED AS A THERMOST AT .

The GB/GW models incorporate an outlet water probe consisting
of two limit controls:

1. An adjustable automatic reset limit control, that can be set to
either 210°F (99°C) or 240°F (115°C) depending on the
application.

2. A fixed manual reset limit factory set at 250°F (121°C). If the
manual reset should open due to high temperature the gas
valves will close and the unit will go into lockout.

If lockout occurs, manually push the ENTER/RESET
push-button on the display panel to restart the boiler.

ON/OFF SWITCH

The ON/OFF switch is a single-pole, single-throw rocker switch.
The switch provides 120VAC from the line source to the boiler.

COMBUSTION AIR BLOWER

Figure 2. Summary of Dip Switch Options.

DIFFERENTIAL PRESSURE SWITCH

The differential pressure switch ensures that a sufficient differential
exists between the air pressure in the pre-mix chamber and the
inlet of the burner for safe, low NOX combustion. The switch has
two pressure taps marked "+" (positive) and "-" (negative). Silicone
tubing is run from the positive pressure tap of the switch to a tap on
the control panel to measure the air pressure in the pre-mix
chamber. The negative pressure tap measures the pressure taken
at the burner's auxiliary tube. Connections can be seen by removing
the lower front jacket panel. It is important that this panel remain
sealed at all times while the boiler is operating.

This differential pressure switch is normally open and closes when
the combustion blower starts.

BLOCKED FLUE PRESSURE SWITCH

The blocked flue pressure switch ensures that the flue gas vent is
clear. This pressure switch is normally closed and only opens on
the fault conditions.

Provides air for combustion process. The blower settings are
adjustable through the use of the air shutter, however, blowers are
set at the factory and should not need adjustment.

T ANK PROBE

FOR HOT WA TER SUPPL Y SYSTEMS (GW models), A tank probe is

supplied with each hot water supply boiler. The inlet water
temperature will default to the tank temperature on the display when
the tank probe is installed.

Note: Tank Probe must be designated as controlling probe using
Dip Switch "D" on Central Control Board before it can be used for
(GW) hot water supply applications.

"Pigtails" of field-supplied wires should be spliced to "pigtails" of
tank probe and connected to terminal block in the 24 volt junction
box. See figure 12 for the tank probe installation. Follow the
instructions for the operation and temperature setting procedures
for the tank probe (see page 29).

FOR HOT WATER HEATING SYSTEMS (GB models) Due
many various types of systems and operating conditions, a tank

5

to the

probe is not supplied with the GB models. A tank probe can be
used as an option to control loop temperature and unit staging.
Additionally, the Inlet Temperature Probe can be used as the loop
thermostat in some heating (GB) applications. These types of
controls connect to designated wires in the junction box at the rear
of the boiler. Do not operate this boiler using the internal high

limits only , you must use an operating thermostat as mentioned
above.

Note: Additional 24V devices or Tank Probe must be identified
using Dip Switches on Central Control Board before they are
recognized as a part of the heating system. See table 5 and refer to
"Multi-Stage Firing and Control System" on previous page for more
information about dip switch settings.

If any safety relief valve is replaced, the replacement valve must
comply with the latest version of the ASME Boiler and Pressure
Vessel Code, Section IV (HEA TING BOILERS). Select a relief valve
with a discharge rating NOT less than the boiler input, and a set
pressure NOT exceeding the working pressure of any component
in the system.

The storage tank temperature and pressure relief valve must
comply with the applicable construction provisions of the Standard
for Relief Valves and Automatic Gas Shut-off Devices for Hot Water
Supply Systems, ANSI Z21.22 or CSA-4.4 (and latest addendums).
The valve must be of the automatic reset type and not embody a
single-use type fusible plug, cartridge or linkage.

CIRCULA TING PUMP

The pump flow rate should not exceed the maximum
recommended flow rate, see table 4.

FOR HOT WA TER SUPPLY SYSTEMS (GW models), ordered with
the circulator as an integral part of the boiler; the pump has been
lubricated at the factory, and future lubrication should be in
accordance with the motor manufacturer's instructions provided
as supplement to this manual.

FOR HOT WA TER HEA TING SYSTEMS (GB models or GW models
ordered without circulator), the circulator is NOT provided and

must be field-installed.

LOW WA TER CUT OFF (Not Supplied)

If low water protection is required by the authorities having
jurisdiction, a low water cutoff switch should be installed
next to the boiler in the outlet water line as shown in
"HYDRONIC INSTALLATION" section. The switch should receive
periodic (every six months) inspection to assure proper operation.
A low water cutoff device of the float type should be flushed every six
months.

DRAIN V AL VE (Not Supplied)

Additional drain valves must be obtained and installed on each
boiler and tank for draining purposes.

SAFETY RELIEF V AL VES

Your local code authority may have other specific relief valve
requirements not covered below.

FOR HOT WATER HEATING SYSTEMS, the boilers are shipped
with a 50 psi pressure relief valve. This relief valve is factory
installed in the water outlet header of the boiler, see figure 1.

FOR HOT WATER SUPPLY SYSTEMS, the boilers are shipped
with a 125 psi pressure relief valve. This relief valve is factory
installed in the water outlet header of the boiler, see figure 1.

This ASME-rated valve has a discharge capacity that exceeds the
maximum boiler input rating and a pressure rating that does not
exceed the maximum working pressure shown on the boiler rating
plate.

In addition, an A.G.A. design-certified and ASME-rated temperature
and pressure (T & P) relief valve must be installed on each and
every water storage tank in the hot water supply system, see
figures 11 and 13.

The T & P relief valve should have a temperature rating of 210°F
(99°C), a pressure rating NOT exceeding the lowest rated working
pressure of any system component, and a discharge capacity
exceeding the total input of the water boilers supplying water to the
storage tank.

Locate the T & P relief valve (a) in the top of the tank, or (b) in the
side of the tank on a center line within the upper six (6) inches
(15 cm) of the top of the tank. The tapping shall be threaded in
accordance with the latest edition of the Standard for Pipe Threads,
General Purpose (inch), ANSI/ASME B1.20.1. The location of, or
intended location for, the T & P relief valve shall be readily
accessible for servicing or replacement.

WARNING

THE PURPOSE OF A SAFETY RELIEF VALVE IS TO AVOID
EXCESSIVE PRESSURE WHICH MAY CAUSE T ANK EXPLOSION,
SYSTEM OR BOILER DAMAGE.

TO A VOID W A TER DAMAGE A DRAIN LINE MUST BE CONNECTED
TO A SAFETY RELIEF VAL VE TO DIRECT DISCHARGE TO A SAFE
LOCATION. A DRAIN LINE MUST NOT BE REDUCED FROM THE
SIZE OF THE VALVE OUTLET AND IT MUST NOT CONTAIN ANY
V ALVES BETWEEN THE BOILER AND THE RELIEF V AL VE OR THE
RELIEF VALVE AND THE DRAIN EXIT. IN ADDITION, THERE
SHOULD NOT BE ANY RESTRICTIONS IN A DRAIN LINE NOR
SHOULD IT BE ROUTED THROUGH AREAS WHERE FREEZING
CONDITIONS MIGHT OCCUR. DO NOT THREAD OR CAP THE
DRAIN LINE EXIT. RESTRICTING OR BLOCKING A DRAIN LINE
WILL DEFEAT THE PURPOSE OF THE RELIEF VALVE AND MAY
CREATE AN UNSAFE CONDITION. INST ALL A DRAIN LINE WITH
A DOWNWARD SLOPE SUCH THAT IT NATURALLY DRAINS
ITSELF.

INST ALLA TION INSTRUCTIONS

REQUIRED ABILITY

INST ALLATION OR SER VICE OF THIS BOILER REQUIRES ABILITY
EQUIVALENT TO THAT OF A LICENSED TRADESMAN IN THE
FIELD INVOLVED. PLUMBING, AIR SUPPLY, VENTING, GAS
SUPPL Y AND ELECTRICAL WORK ARE REQUIRED.

LOCA TION

When installing the boiler, consideration must be given to proper
location. Location selected should be as close to the stack or
chimney as practical with adequate air supply and as centralized
with the piping system as possible. This location should also be
such that the gas ignition system components are protected from
water (dripping, spraying, etc.) during appliance operation and
service (circulator replacement, control replacement, etc.)

6

• THE BOILER MUST NOT BE INST ALLED ON CARPETING.

• THE BOILER SHOULD NOT BE LOCA TED IN AN AREA WHERE

IT WILL BE SUBJECT TO FREEZING.

• THE BOILER SHOULD BE LOCA TED NEAR A FLOOR DRAIN.

• THE BOILER SHOULD BE LOCATED IN AN AREA WHERE

LEAKAGE FROM THE BOILER OR CONNECTIONS WILL NOT
RESULT IN DAMAGE TO THE ADJACENT AREA OR T O LOWER
FLOORS OF THE STRUCTURE.

WHEN SUCH LOCATIONS CANNOT BE AVOIDED, A SUITABLE
DRAIN PAN SHOULD BE INST ALLED UNDER THE BOILER. Such
pans should be fabricated with sides at least 2-1/2" (6.5 cm) deep,
with length and width at least 2" (5.1 cm) greater than the dimensions
of the boiler and must be piped to an adequate drain. The pan
must not restrict combustion air flow.

WARNING

THERE IS A RISK IN USING FUEL BURNING APPLIANCES IN
ROOMS OR AREAS WHERE GASOLINE, OTHER FLAMMABLE
LIQUIDS OR ENGINE DRIVEN EQUIPMENT OR VEHICLES ARE
STORED, OPERA TED OR REP AIRED. FLAMMABLE VAPORS ARE
HEAVY AND TRAVEL ALONG THE FLOOR AND MAY BE IGNITED
BY THE IGNITER OR MAIN BURNER FLAMES CAUSING FIRE OR
EXPLOSION. SOME LOCAL CODES PERMIT OPERA TION OF GAS
APPLIANCES IF INSTALLED 18 INCHES (46.0 CM) OR MORE
ABOVE THE FLOOR. THIS MA Y REDUCE THE RISK IF LOCA TION
IN SUCH AN AREA CANNOT BE A VOIDED.

FLAMMABLE ITEMS, PRESSURIZED CONTAINERS OR ANY
OTHER POTENTIAL FIRE HAZARDOUS ARTICLES MUST NEVER
BE PLACED ON OR ADJACENT TO THE BOILER.

OPEN CONTAINERS OF FLAMMABLE MATERIAL SHOULD NOT
BE STORED OR USED IN THE SAME ROOM WITH THE BOILER.

INST ALLATION CLEARANCES

Sufficient area should be provided at the front and sides of the
unit for proper servicing. For ease of service, minimum
clearances of 24" (61.0 cm) in the front and 18" (46.0 cm) on
the sides are recommended. It is important that the minimum
clearances be observed to allow service to the control box and
other controls. Observing proper clearances will allow service

to be performed without movement or removal of the boiler from
its installed location. Failure to observe minimum clearances
may require removal of the boiler in order to service such items as
the heat exchanger and burners. In a utility room installation, the
door shall be wide enough to allow the boiler to enter or to permit
the replacement of another appliance.

Two inch (5.1 cm) clearance is allowable from combustible
construction to hot water pipes. Sufficient clearance should be
provided at one end of the boiler to permit access to heat exchanger
tubes for cleaning.

Access to control box items such as the Central Control Board,
Ignition Control Boards and wiring harnesses is provided through
a panel on the left side of the unit. An 18" (46.0 cm) minimum
clearance is recommended.

These boilers are approved for installation on noncombustible
flooring in an alcove with minimum clearance to combustibles of:
3 inches (7.6 cm) Right Side, and Back; 6 inches (15.2 cm) Top,
Front Alcove, 12 inches (30.5 cm) Left Side and 6 inches (15.2 cm)
Vent.

For installation on combustible flooring use the Combustible Floor
Kit. The combustible floor kit base adds 4" (10.1 cm) to the overall
height of the boiler. See figure 3.

If the boiler is installed above the level of heating system terminal
units, a low water cutoff device must be installed in the boiler outlet
at the time of installation.

For installation locations with elevations above 4,500 feet
(1350 m), consult the factory.

WARNING

UNDER NO CIRCUMST ANCES SHOULD THE EQUIPMENT ROOM
WHERE THE BOILER IS INSTALLED EVER BE UNDER NEGA TIVE
PRESSURE. PARTICULAR CARE MUST BE TAKEN WHEN
EXHAUST FANS, COMPRESSORS, AIR HANDLING EQUIPMENT,
ETC., MAY INTERFERE WITH THE COMBUSTION AND
VENTILA TION AIR SUPPLIES OF THIS BOILER.

CHEMICAL V APOR CORROSION

Heat exchanger corrosion and component failure can be caused
by the heating and breakdown of airborne chemical vapors. Spray
can propellants, cleaning solvents, refrigerator and air conditioning
refrigerants, swimming pool chemicals, calcium and sodium
chloride, waxes, and process chemicals are typical compounds
which are corrosive. These materials are corrosive at very low
concentration levels with little or no odor to reveal their presence.

Products of this sort should not be stored near the boiler. Also, air
which is brought in contact with the boiler should not contain any of
these chemicals. If necessary, uncontaminated air should be
obtained from remote or outside sources. Failure to observe this

requirement will void the warranty.

MODEL COMBUSTIBLE FLOOR KIT NO.
(GB/GW)-1000 211093
(GB/GW)-1300 211093-1
(GB/GW)-1500 211093-2
(GB/GW)-1850 211093-3
(GB/GW)-2100 211093-4
(GB/GW)-2500 211093-5

Figure 3: Boiler on Combustible Floor Base and Kit Numbers

LEVELLING

Each unit must be checked after installation to be certain that it is
level.

AIR REQUIREMENTS

WARNING

FOR SAFE OPERATION, AN AMPLE SUPPLY OF AIR MUST BE

7

PROVIDED FOR PROPER COMBUSTION AND VENTILATION IN
ACCORDANCE WITH
Z223.1 OR CAN/CSA-B149.1 AND .2 (LATEST EDITIONS) OR
APPLICABLE PROVISIONS OF THE LOCAL BUILDING CODES.
AN INSUFFICIENT SUPPL Y OF AIR MAY RESULT IN A YELLOW ,
LUMINOUS BURNER FLAME, CARBONING OR SOOTING OF THE
FINNED HEAT EXCHANGER, OR CREATE A RISK OF
ASPHYXIATION. DO NOT OBSTRUCT THE FLOW OF
COMBUSTION AND VENTILATION AIR.

THE NATIONAL FUEL GAS CODE, ANSI

UNCONFINED SP ACE

sufficient openings for air must be provided in the walls.
UNDERSIZED OPENINGS WILL CAUSE AIR TO BE DRAWN INTO
THE ROOM THROUGH THE CHIMNEY, CAUSING POOR
COMBUSTION. SOOTING MAY RESULT WITH AN INCREASED
RISK OF ASPHYXIA TION.

VENTING

!

This boiler is approved to be vented as a Category I, Category III
(horizontal venting), or a Direct V ent appliance. The Horizont al and
Direct Venting options require a special vent kit.

In buildings of conventional frame, brick or stone construction,
unconfined spaces may provide adequate air for combustion.

If the unconfined space is within a building of tight construction
(buildings using the following construction: weather stripping, heavy
insulation, caulking, vapor barrier, etc.), air for combustion,
ventilation, must be obtained from outdoors or spaces freely
communicating with the outdoors. The installation instructions for
confined spaces in tightly constructed buildings must be followed
to ensure adequate air supply.

CONFINED SP ACE

(a) U. S. INST ALLATIONS
When drawing combustion and dilution air from inside a
conventionally constructed building to a confined space, such a
space shall be provided with two permanent openings, ONE
WITHIN 12 INCHES OF THE ENCLOSURE TOP AND ONE WITHIN
12 INCHES OF THE ENCLOSURE BOTTOM. Each opening shall
have a free area of at least one square inch per 1000 Btuh of the
total input of all appliances in the enclosure, but not less than 100
square inches.

If the confined space is within a building of tight construction, air for
combustion, ventilation, and draft hood dilution must be obtained
from outdoors. When directly communicating with the outdoors or
communicating with the outdoors through vertical ducts, two
permanent openings, located in the above manner, shall be
provided. Each opening shall have a free area of not less than one
square inch per 4000 Btuh of the total input of all appliances in the
enclosure. If horizontal ducts are used, each opening shall have a
free area of not less than one square inch per 2000 Btuh of the total
input of all appliances in the enclosure.

(b) CANADIAN INSTALLA TIONS
Ventilation of the space occupied by the boiler(s) shall be provided
by an opening for ventilation air at the highest practical point
communicating with outdoors. The total cross- sectional area shall
be at least 10% of the area of the combustion air opening but in no
case shall the cross-sectional area be less than 10 square inches
(6500 mm

In addition to the above, there shall be permanent air supply
opening(s) having a cross-sectional area of not less than 1 square
inch per 7,000 BTUH (310 mm
BTUH
BTUH. This opening(s) shall be located at, or ducted to, a point
neither more than 18" (46.0 cm) nor less than 6 inches (15.2 cm)
above the floor level.

Where power vented equipment is used in the same room as the
boiler, sufficient air openings must be supplied. UNDERSIZED
OPENINGS MAY RESULT IN INSUFFICIENT AIR FOR
COMBUSTION.

Where an exhaust fan is installed in the same room with a boiler,

2

).

2

/KW) up to and including 1,000,000

plus 1 square inch per 14,000 BTU in excess of 1,000,000

TABLE 6: DIRECT VENT KITS
Horiz. or Horiz. Direct Vent Kit No. Model Number

211090 G(W,B) 1000
211090-1 G(W,B) 1300
211090-1 G(W,B) 1500
211090-4 G(W,B) 1850
211090-2 G(W,B) 2100
211090-3 G(W,B) 2500

Vertical Direct V ent Kit No. Model Number

211089 G(W,B) 1000
211089-1 G(W,B) 1300
211089-1 G(W,B) 1500
211089-4 G(W,B) 1850
211089-2 G(W,B) 2100
211089-3 G(W,B) 2500

CAUTION

WHEN VENTING THE GENESIS BOILER THROUGH AN
OVERSIZED CHIMNEY (INCLUDING MASONRY CHIMNEYS),
ADDITIONAL CARE MUST BE EXERCISED TO ASSURE PROPER
DRAFT . FOR PROPER OPERA TION, A MINIMUM DRAFT OF -0.02"
W.C. AND A MAXIMUM DRAFT OF -0.04" W .C. MUST BE MAINT AINED.
IN INSTANCES OF EXCESSIVE DRAFT, A BAROMETRIC DAMPER
MAY BE REQUIRED TO ASSIST IN MAINTAINING THE PROPER
DRAFT . DRAFT SHOULD BE MEASURED 2 FEET (0.6 M) ABOVE
THE BOILER VENT COLLAR.

WARNING

THE INSTRUCTIONS IN THIS SECTION ON VENTING THE BOILER
MUST BE FOLLOWED TO AVOID CHOKED COMBUSTION OR
RECIRCULATION OF FLUE GASES. SUCH CONDITIONS CAUSE
SOOTING OR RISKS OF FIRE AND ASPHYXIA TION.

CONNECTING BOILER TO A COMMON VENT

Do not connect the boiler to a common vent or chimney with solid
fuel burning equipment. This practice is prohibited by most local
building codes as is the practice of venting gas fired equipment to
the duct work of ventilation systems.

Where a separate vent connection is not available and the vent
pipe from the boiler must be connected to a common vent with an
oil burning furnace, the vent pipe should enter the common vent or
chimney at a point ABOVE the flue pipe from the oil furnace.

UL/ULC listed double wall type B-1 gas vents, through 16" diameter ,
can be installed in heated and unheated areas and can pass
through floors, ceilings, partitions, walls and roofs, provided the
required clearance is observed.

At the time of removal of an existing boiler, the following step s shall
be followed with each appliance remaining connected to the
common venting system. Perform these steps while the other
appliances remaining connected to the common venting system
are not in operation.

8

1. Seal any unused opening in the common venting system.

2. Visually inspect the venting system for proper size and horizontal
pitch and determine there is no blockage or restriction, leakage,
corrosion or other unsafe condition.

3. Isolate the space containing the appliance(s) remaining
connected to the common venting system as much as possible
by closing all openings (windows, doors, etc.) connected to
other spaces in the building. Turn on any exhaust fans to their
maximum setting and close fireplace dampers. Note: DO NOT
operate summer exhaust fan.

4. Test fire the appliance(s) being inspected, making sure to follow
the manufacturers lighting and operating instructions.
Appliance(s) operating controls should be adjusted to provide
continuous service.

5. Check vent pressure of appliance 24 inches (61.0 cm) above
boiler vent collar. Vent pressure should be maintained between

-0.02" W. C. and -0.04" W.C. to assure proper operation. For
appliances with a draft hood, check for spillage with mirror,
smoke or other device five minutes after placing appliance in
operation.

6. After it has been determined that each appliance remaining
connected to the common venting system properly vents when
tested as outlined above, return doors, windows, exhaust fans,
fireplace dampers and other gas burning appliances to their
previous conditions of use.

All boiler venting systems shall be installed in accordance with the
National Fuel Gas Code, ANSI Z223.1 or CAN/CSA-B149.1 and .2
(and latest addendums), or applicable provisions of the local
building codes.

LOCATION REQUIREMENTS (INT AKE/EXHAUST)

Intake/Exhaust Installation Requirements (See figure 4):

1. The termination must be 12 inches (30.5 cm) above snow or
grade level whichever is higher.

2. Due to normal formation of water vapor in the combustion
process, horizontal terminations must not be located over areas
of pedestrian or vehicular traffic, i.e. public walkways or over
areas where condensate could create a nuisance or hazard.
This is especially true in colder climates where ice buildup is
likely to occur. A.O. Smith Corporation will not be held liable for
any personal injury or property damage due to any dislodging
of ice.

3. The minimum distance for any window, gravity air inlet to a
building, or from gas or electric meter(s) is 6 feet (1.8 m)
horizontally , 4 feet (1.2 m) below and 24 inches (61.0 cm) above.

4. The minimum distance from inside corner formed by two
exterior walls is 6 feet (1.8 m) but 10 feet (3.1 m) is
recommended where possible.

5. Maintain a minimum distance of 4 feet (1.2 m) from any soffit or eve
vent to the exhaust terminal.

6. Maintain a minimum distance of 10 feet (3.1 m) from any forced
air inlet to a building. Any fresh air or make up air inlet such as
a dryer or furnace area is considered to be a forced air inlet.

7. Avoid areas where condensate drainage may cause problems
such as above planters, patios, or adjacent to windows where
the steam from the flue gases may cause fogging.

8. Select the point of wall penetration where the minimum 1/4" per
foot (2 cm/m) of slope up can be maintained.

9. The through the wall termination kit is suitable for zero clearance
to combustible materials.

10. The mid point of the termination elbow must be a minimum of
12 inches (30.5 cm) from the exterior wall.

Direct venting into dead air spaces such as alleys, atriums and

CAUTION

inside corners can cause recirculation of flue gases.
Recirculation of flue gases will cause sooting, premature failure
of the heat exchanger and icing of the combustion air intake
during severe cold weather. T o prevent the recirculation of flue
gases, maintain as much distance as possible between the
combustion air intake and the exhaust vent terminal.

Figure 4. Vent T ermination Inst allation Clearances

9

STANDARD VENT - VERTICAL (CATEGORY I)

IMPORT ANT!

VENT PRESSURE MUST BE MAINT AINED

BETWEEN -0.02" W.C. AND -0.04" W.C. AT 24"

(61.0 cm) ABOVE BOILER COLLAR.

Figure 5.

T ABLE 7. ST ANDARD VERTICAL VENTING (CA TEGORY I)

APPLIANCE CERTIFIED EXHAUST MAXIMUM LENGTH WITHOUT

MODEL CA TEGOR Y VENTING VENT SIZE BAROMETRIC DAMPER (FEET)

MA TERIAL (INCHES)

I000
1300 TYPE B OR 35 Feet (10.7 m) without damper

1500 EQUIVALENT 12" (30.5 cm) *70 Feet (21.3 m) max. with damper
1850 TYPE B OR 14"(35.6 cm) 35 Feet (10.7 m) without damper

2100 EQUIVALENT *70 Feet (21.3 m) max. with damper

2500

* Extending venting over 70 feet (21.3 m) may require special considerations.

• Connection for the appliance exhaust vent to the stack must be as direct as possible. Maximum and minimum venting length
for Category I appliances shall be determined per the latest edition of the National Fuel Code (U.S.) and CAN/CSA-B149.1
and .2 Installation Code (Canada).

• The horizontal breaching of a vent must have an upward slope of not less than 1/4 inch per linear foot (2 cm/m) from the boiler
to the vent terminal. The horizontal portion of the vent shall be supported to maintain clearances and to prevent physical damage
or separation of joints.

I

I

I

I

TYPE B OR 10”(25.4 cm) 35 Feet (10.7 m) without damper

EQUIV ALENT *70 Feet (21.3 m) max. with damper

TYPE B OR 16" (40.6 cm) 35 Feet (10.7 m) without damper

EQUIV ALENT *70 Feet (21.3 m) max. with damper

10

STANDARD VENT - HORIZONTAL (CATEGORY III)

Figure 6.

T ABLE 8. ST ANDARD HORIZONT AL VENTING (CA TEGORY III)

APPLIANCE CERTIFIED EXHAUST MAXIMUM

MODEL CA TEGOR Y VENTING VENT SIZE VENT LENGTH

MA TERIAL (INCHES) (FEET)

I000

1300 STAINLESS
1500 STEEL

1850 STAINLESS
2100 STEEL

2500

WARNING: No substitutions of flue pipe or vent cap material are allowed. Such substitutions would jeopardize the
safety and health of inhabitants.

• A maximum of two elbows can be used on inlet and outlet vent piping respectively. Each elbow is equal to 10 feet (3 m) of
straight pipe.

III

III

III

III

ST AINLESS

STEEL

ST AINLESS

STEEL

10”(25.4 cm)

12" (30.5 cm)

14"(35.6 cm)

16" (40.6 cm)

70' (21.3 m)

70' (21.3 m)

70' (21.3 m)

70' (21.3 m)

• Use only special gas vent pipes listed for use with Category III gas burning heaters, such as stainless steel Saf-T-Vent
by Heat Fab, Inc., available from A.O. Smith WPC, 5621 W. 115th Street, Alsip, IL 60803 Phone: [phone] or
Fax: [phone]. Pipe joints must be positively sealed.

11