A.O. Smith BTR 500, Instruction Manual

Page: 11 / 52

11
Breathing Hazard - Carbon Monoxide Gas
Breathing carbon monoxide can cause brain damage or
death. Always read and understand instruction manual.
Under no circumstances should
the input exceed the rate shown
on the water heater’s rating label.
Overfiring could result in damage to
the water heater and sooting.
Gas and carbon monoxide detectors
are available.
propane installations
InSTALLATIOnS ABOVe 2000 FeeT (610 meTerS) reQUIre
rePLACemenT OF BUrner OrIFICeS In ACCOrDAnCe
WITh CUrrenT eDITIOn OF The nATIOnAL FUeL GAS CODe
(AnSI Z223.1). FOr CAnADIAn InSTALLATIOnS COnSULT
CAnADIAn InSTALLATIOnS CODe CAn/CSA B149.1. FAILUre
TO rePLACe OrIFICeS WILL reSULT In ImPrOPer AnD
IneFFICIenT OPerATIOn OF The APPLIAnCe reSULTInG
In The PrODUCTIOn OF InCreASeD LeVeLS OF CArBOn
mOnOXIDe GAS In eXCeSS OF SAFe LImITS WhICh COULD
reSULT In SerIOUS PerSOnAL InJUry Or DeATh.
you should contact your gas supplier for any specific changes
which may be required in your area.
As elevation above sea level is increased, there is less oxygen
per cubic foot of air. Therefore, the heater input rate should
be reduced at high altitudes for satisfactory operation with the
reduced oxygen supply. Failure to make this reduction would
result in an over firing of the heater causing sooting, poor
combustion and/or unsatisfactory heater performance.
ratings specified by manufacturers for most appliances apply for
elevations up to 2000 feet (610m). For elevations above 2000 feet
(610), ratings must be reduced at the rate of 4% for each 1000
feet (305m) above sea level. For example, if a heater is rated at
78,000 Btuh (22.9 kwh) at sea level, to rate the heater at 4000 feet
(1219m), you subtract 4 (once for each thousand feet) x.04 (4%
input reduction) x 78,000 (original rating) from the original rating.
Therefore, to calculate the input rating at 4,000 feet (1219m): 4 x
.04 x 78,000 = 12,480 Btuh (3.7 kwh), 78,000 (22.9 kwh) - 12,480
(3.7 kwh) = 65,520 Btuh (19.2 kwh). At 6000 feet (1829m) the
correct input rating should be 59,280 Btuh (17.4 kwh).
natural gas installations
The natural gas fired version of the water heater covered by this
manual is certified for use without modification for altitudes up to
10,100 feet.
For installations above 10,100 feet call the technical support
phone number listed on the back cover of this manual for further
technical assistance. Call the local gas or utility company to verify
Btu per cubic foot content before calling for technical assistance
and have that information available.
note: The actual firing rate of the water heater must not exceed
the input rating on the water heater's rating label under any
circumstances.
note: Due to the input rating reduction at high altitudes, the
output rating of the appliance is also reduced and should be
compensated for in the sizing of the equipment for applications.
See the Circulation Pump Wiring Diagrams (Figure 8, Figure
9) in this manual for electrical hookup information. Install in
accordance with the current edition of the national electrical
Code, nFPA 70 or the Canadian electrical Code, CSA C22.1.
All-bronze circulators are recommended for used with commercial
water heaters.
Some circulating pumps are manufactured with sealed bearings
and do not require further lubrication. Some circulating pumps
must be periodically oiled. refer to the pump manufacturer’s
instructions for lubrication requirements.
CIRCULATING PUMP WIRING DIAGRAM
STORAGE TANK OR BUILDING RECIRCULATION
FIELD SUPPLIED TEMPERATURE CONTROL
INSTALLED IN THE STORAGE TANK
OR CIRCULATING LOOP RETURN LINE
CIRC
PUMP
MOTOR
L1 HOT
L2 NEUTRAL
120 VAC
POWER
NOTE: USE SEPARATE 120 VAC POWER
SUPPLY FOR PUMP CIRCUIT. DO NOT
SHARE POWER WITH APPLIANCE AS THIS
MAY CAUSE ELECTRICAL LINE NOISE AND
LEAD TO ERRATIC CONTROL SYSTEM
OPERATION.
CIRCULATING PUMP WIRING DIAGRAM
DISHWASHER LOOP WITH TOGGLE SWITCH
FIELD SUPPLIED TEMPERATURE
CONTROL INSTALLED IN THE
CIRCULATING LOOP RETURN LINE
DISHWASHER
TOGGLE
SWITCH
CIRC
PUMP
MOTOR
L1 HOT
L2 NEUTRAL
120 VAC
POWER
NOTE: USE SEPARATE 120 VAC POWER
SUPPLY FOR PUMP CIRCUIT. DO NOT
SHARE POWER WITH APPLIANCE AS THIS
MAY CAUSE ELECTRICAL LINE NOISE AND
LEAD TO ERRATIC CONTROL SYSTEM
OPERATION.
figure 8.
CIRCULATING PUMP WIRING DIAGRAM
STORAGE TANK OR BUILDING RECIRCULATION
FIELD SUPPLIED TEMPERATURE CONTROL
INSTALLED IN THE STORAGE TANK
OR CIRCULATING LOOP RETURN LINE
CIRC
PUMP
MOTOR
L1 HOT
L2 NEUTRAL
120 VAC
POWER
NOTE: USE SEPARATE 120 VAC POWER
SUPPLY FOR PUMP CIRCUIT. DO NOT
SHARE POWER WITH APPLIANCE AS THIS
MAY CAUSE ELECTRICAL LINE NOISE AND
LEAD TO ERRATIC CONTROL SYSTEM
OPERATION.
CIRCULATING PUMP WIRING DIAGRAM
DISHWASHER LOOP WITH TOGGLE SWITCH
FIELD SUPPLIED TEMPERATURE
CONTROL INSTALLED IN THE
CIRCULATING LOOP RETURN LINE
DISHWASHER
TOGGLE
SWITCH
CIRC
PUMP
MOTOR
L1 HOT
L2 NEUTRAL
120 VAC
POWER
NOTE: USE SEPARATE 120 VAC POWER
SUPPLY FOR PUMP CIRCUIT. DO NOT
SHARE POWER WITH APPLIANCE AS THIS
MAY CAUSE ELECTRICAL LINE NOISE AND
LEAD TO ERRATIC CONTROL SYSTEM
OPERATION.
figure 9.
high altitude installations
Fire and Explosion Hazard
Gas and carbon monoxide detectors are
available.
Overfiring could result in fire or
explosion.
Under no circumstances should the
input exceed the rate shown on the
water heater’s rating label.