A.O. Smith GB-GW-650, GB-GW-200, GB-GW-500, GB-GW-400, GB-GW-750 User Manual

GAS-FIRED COMMERCIAL

COPPER BOILERS

FOR HYDRONIC HEATING

AND HOT WATER SUPPLY

USER'S INFORMATION MANUAL

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.

WARNING

Should overheating occur or the gas supply fail to shut off, do
not turn off or disconnect the electrical supply to the pump.
Instead, shut off the gas supply at a location external to the
appliance.

GB/GW-200, -300, -400, -500, -650, -750

SERIES 200, 201, 202, 203

LIGHTING INSTRUCTIONS

These models have an automatic hot surface ignition system
mounted on the combustion chamber panel inside the front jacket.
This hot surface igniter ignites the main burner gas whenever the
system control calls for heat.

Before proceeding with operation of the unit, make sure the boiler
and system are filled with water and all air is expelled from the boiler,
radiator tank(s) and piping.

WARNING
THE MAIN MANUAL GAS SHUT-OFF VALVE MUST HAVE BEEN
CLOSED FOR AT LEAST FIVE (5) MINUTES BEFORE
LIGHTING. This waiting period is an important safety step.
Its purpose is to permit gas that might have accumulated in
the combustion chamber to clear. IF YOU DETECT GAS AT
THE END OF THE PERIOD DO NOT PROCEED WITH
LIGHTING. RECOGNIZE THAT GAS ODOR, EVEN IF IT SEEMS
WEAK, MAY INDICATE PRESENCE OF ACCUMULATED GAS
SOMEPLACE IN THE AREA WITH A RISK OF FIRE OR
EXPLOSION.

WARNING

THERE IS A RISK IN USING FUEL BURNING APPLIANCES SUCH
AS GAS WATER BOILERS IN ROOMS, GARAGES OR OTHER
AREAS WHERE GASOLINE AND OTHER FLAMMABLE LIQUIDS
ARE USED OR STORED, OR ENGINE-DRIVEN EQUIPMENT OR
VEHICLES ARE STORED, OPERATED OR REPAIRED.
FLAMMABLE VAPORS ARE HEAVY AND TRAVEL ALONG THE
FLOOR AND MAY BE IGNITED BY THE BOILER'S MAIN BURNER
FLAMES CAUSING FIRE OR EXPLOSION. Some local codes

permit operation of gas appliances if installed 18 inches or more
above the floor. This may reduce the risk if location in such an
area cannot be avoided.

INDEX PAGE

GENERAL . . . . . . . . . . . . . . . . . . . . . . . 1

LIGHTING INSTRUCTIONS . . . . . . . . 2 - 3

OPERATING SEQUENCE,
IGNITION CONTROL AND DIA-SCAN II

INSTRUCTIONS. . . . . . . . . . . . . . 4 - 8

MAINTENANCE . . . . . . . . . . . . . . 8

CONNECTION DIAGRAM 9

WARRANTY. . . . . . . . . . . . . . . . . . . . . . 10

Do not use this boiler if any part has been under water.
Immediately call a qualified service technician to inspect the
boiler and to replace any part of the control system and any
gas control which has been under water.

PRINTED IN U.S.A. 2527 300

WARNING

PLEASE KEEP THESE INSTRUCTIONS ADJACENT TO BOILER AND

NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE.

A DIVISION OF A.O. SMITH CORPORATION

EL PASO, TX MC BEE, SC RENTON, WA

STRATFORD, ONTARIO

VELDHOVEN, THE NETHERLANDS

www.hotwater.com

PART NO. 210890-000 REV. 1

1

SUPERSEDES PART NO. 210311-000

THE UNIT SHOULD NOT BE INSTALLED DIRECTLY ON A
CARPETED FLOOR. A FIRE HAZARD MAY RESULT. Instead,
the boiler must be installed on the A. O. Smith Combustible Floor
Kit Base or concrete blocks extending beyond the full width and
depth of the boiler by at least 3 (76.2mm) inches. If the boiler is
installed in a carpeted alcove, the entire floor must be covered with
concrete blocks, or use the A. O. Smith Combustible Floor Kit Base.

FLAMMABLE ITEMS, PRESSURIZED CONTAINERS OR ANY
OTHER POTENTIAL FIRE HAZARDOUS ARTICLES MUST NEVER

Lighting Instructions for the G(B/W) 200 through 500 models

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.

Light the unit in accordance with the instructions on the lighting and
operating label attached to the boiler. These instructions are
repeated on the following two pages.

2

Lighting Instructions for the G(B/W) 650 and 750 models

.

3