A.O. Smith GB-650: GB-750 User's Information Manual
1
A DIVISION OF A. O. SMITH CORPORATION
MC BEE, SC., RENTON, WA.,
STRATFORD-ONTARIO, VELDHOVEN-THE NETHERLANDS
www.hotwater.com
GAS-FIRED COMMERCIAL
COPPER BOILERS FOR HYDRONIC
HEATING AND HOT WATER SUPPLY
USER'S INFORMATION MANUAL
GB/GW-300, 400, 500, 650, 750
SERIES 400, 401, 402, 403, 404, 405,
2-STAGE UNITS
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.
PLEASE KEEP THESE INSTRUCTIONS ADJACENT TO BOILER AND
NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE.
PART NO. 212132-001
PRINTED IN U.S.A. 0306
INDEX
PAGE
LIGHTING INSTRUCTIONS ....................................... 2-3
MAINTENANCE .......................................................... 3-4
OPERATING SEQUENCE, EMC5000 ......................... 8-14
CONNECTION DIAGRAM ............................................ 13
EMC5000 INSTRUCTIONS ...................................... 14-18
WARRANTY ................................................................. 19
WARNING
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.
CAUTION
TEXT PRINTED OR OUTLINED IN RED CONTAINS
INFORMATION RELATIVE TO YOUR SAFETY. PLEASE READ
THOROUGHLY BEFORE INSTALLING AND USING THIS
APPLIANCE.
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:
• 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.