AO Smith Water Heater 300A User Guide

CYCLONE Xi® Model BTH 300A, 400A, 500A  
COMMERCIAL GAS WATER HEATER  
GAS-FIRED POWER BURNER  
FOR DOMESTIC HOT WATER  
• INSTALLATION • OPERATION • SERVICE • MAINTENANCE • LIMITED WARRANTY  
WARNING: If the information in these  
instructions is not followed exactly, a fire  
or explosion may result causing property  
damage, personal injury or death.  
– 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.  
Thank you for buying this energy efficient water heater from  
A.O. Smith Water Products Company. We appreciate your  
confidence in our products.  
CAUTION  
TEXT PRINTED OR OUTLINED IN RED CONTAINS  
INFORMATION RELATIVE TO YOUR SAFETY. PLEASE  
READ THOROUGHLY BEFORE INSTALLINGAND USING  
THIS APPLIANCE.  
PLACE THESE INSTRUCTIONS ADJACENT TO HEATER AND NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE.  
PRINTED 0307  
ꢀ97373-003  
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ROUGH-IN-DIMENSIONS  
GAS VALVE PIPING  
BTH-300 1 1/4" NPT  
BTH-400 1 1/4" NPT  
BTH-500 1 1/2" NPT  
TABLE 1 RECOVERY CAPACITIES.  
U.S. Gallons/Hr and Litres/Hr at TEMPERATURE RISE INDICATED  
TYPE OF  
GAS  
INPUT  
BTUH  
Approx.  
F°  
20F°  
11C°  
1746  
6610  
1746  
6610  
2328  
8813  
2328  
8813  
2878  
30F° 40F° 50F° 60F° 70F° 80F° 90F° 100F° 110° 120F° 130F° 140F°  
MODEL  
KW  
88  
Capacity  
C°  
17C° 22C° 28C° 33C° 39C° 44C° 50C° 56C° 61C° 67C° 72C°  
1164 873 699 582 499 436 388 349 318 291 269  
4406 3304 2644 2203 1888 1652 1469 1322 1201 1102 1017  
1164 873 699 582 499 436 388 349 318 291 269  
4406 3304 2644 2203 1888 1652 1469 1322 1201 1102 1017  
1552 1164 931 776 665 582 517 466 423 388 359  
78C°  
250  
945  
250  
945  
332  
300,000  
300,000  
399,900  
399,900  
499,900  
499,900  
130 US Gals. GPH  
492 Litres LPH  
130 US Gals. GPH  
492 Litres LPH  
130 US Gals. GPH  
492 Litres LPH  
130 US Gals. GPH  
492 Litres LPH  
130 US Gals. GPH  
492 Litres  
130 US Gals. GPH  
492 Litres LPH 10894 7263 5447 4358 3631 3113 2724 2421 2179 1981 1816 1676 1556  
BTH-300 NATURAL  
BTH-300 PROPANE  
88  
NATURAL  
BTH-400  
117  
117  
146  
146  
5875 4406 3525 2938 2518 2203 1958 1763 1602 1469 1356 1259  
1552 1164 931 776 665 582 517 466 423 388 359 332  
5875 4406 3525 2938 2518 2203 1958 1763 1602 1469 1356 1259  
1919 1439 1151 959 822 720 640 576 523 480 443 411  
BTH-400 PROPANE  
BTH-500 NATURAL  
LPH 10894 7263 5447 4358 3631 3113 2724 2421 2179 1981 1816 1676 1556  
2878 1919 1439 1151 959 822 720 640 576 523 480 443 411  
BTH-500 PROPANE  
Recovery capacities are based on heater performance at 96% thermal efficiency for BTH 300A, 400A, and 95% thermal efficiency for BTH 500A.  
FOREWORD  
These designs comply with the current edition of the American  
National Standard for Gas Water Heaters, Volume III,  
ANSI Z21.10.3 / CSA 4.3 as an automatic circulating tank water  
heater, and automatic storage water heaters.  
In addition to these instructions, the equipment 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.  
Detailed installation diagrams are found in this manual. These  
diagrams will serve to provide the installer with a reference for the  
materials and methods of piping necessary. It is highly essential  
that all water, gas piping and wiring be installed as shown on the  
diagrams.  
In the absence of local codes, the installation must comply  
with the current editions of the National Fuel Gas Code,  
ANSI Z223.1/NFPA 54 and the National Electrical Code,  
NFPA 70 or CAN/CSA-B149.1, the Natural Gas and Propane  
Installation Code and CSA C22.1, the Canadian Electrical Code. All  
documents are available from the Canadian StandardsAssociation,  
8501 East Pleasant Valley Road, Cleveland, OH 44131. NFPA  
documents are also available from the National Fire Protection  
Association, 1 Batterymarch Park, Quincy, MA 02269.  
Particular attention should be given to the installation of thermometers  
at the locations indicated on the diagrams as these are necessary  
for checking the proper functioning of the heater.  
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TABLE OF CONTENTS  
Water (Potable) Heating & Space Heating..........................................7  
ROUGH-IN DIMENSIONS.........................................................................ꢁ  
FOREWORD .............................................................................................ꢁ  
FEATURES................................................................................................3  
Water Temperature Control................................................................3-5  
Water Temperature Setpoint Adjustment Procedure.............................5  
High Limit Switch (E.C.O.) ....................................................................5  
Dishwashing Machine Requirement......................................................5  
Circulating Pump...................................................................................6  
INSTALLATION INSTRUCTIONS .............................................................6  
Required Ability .....................................................................................6  
Insulation Blankets................................................................................6  
Locating The Heater..............................................................................6  
Clearances............................................................................................7  
Hard Water............................................................................................7  
Air Requirements ..................................................................................7  
Mechanical Exhausting of Room Air .....................................................7  
Unconfined Space.................................................................................7  
Confined Space.....................................................................................7  
Chemical Vapor Corrosion ....................................................................7  
Installation Requirements for the  
Commonwealth of Massachusetts ........................................................8  
VENTING..............................................................................................8-ꢀꢀ  
Vent Pipe Termination ......................................................................... ꢀꢀ  
Direct Venting...................................................................................... ꢀꢀ  
Direct Vent Terminal Installation.....................................................ꢀ-ꢀꢁ  
Installation Sequence..........................................................................ꢁ  
Vertical Vent Terminal Installation .......................................................ꢁ  
Installation Sequence.....................................................................ꢀꢁ-ꢀ3  
Installation of Vent System..................................................................3  
Vent Pipe Preparation .........................................................................14  
CONTROLS AND SWITCHES ................................................................14  
Blower Prover Switch..........................................................................14  
Blocked Outlet Prover Switch..............................................................14  
Blocked Inlet Prover Switch ................................................................14  
Low Gas Pressure Switch...................................................................14  
On/Off Switch.................................................................................14-15  
Hot Surface Igniter ..............................................................................5  
GAS PIPING............................................................................................5  
Connection of Gas Pipe .................................................................15-16  
Purging................................................................................................16  
Gas Meter Size - City Gases Only ......................................................16  
Gas Valves..........................................................................................16  
SYSTEM CONNECTIONS ......................................................................16  
Thermometers.....................................................................................16  
Relief Valve .........................................................................................16  
Water Line Connections......................................................................16  
Closed System...............................................................................16-17  
Heater Wiring .................................................................................ꢀ7-ꢀ9  
OPERATION............................................................................................0  
Sequence of Operation .......................................................................0  
ELECTRONIC CONTROL.......................................................................0  
Overview .............................................................................................0  
Operating States ............................................................................ꢁ0-ꢁꢀ  
Adjusting the Operating Set Point.......................................................ꢀ  
Changing the Display Units.................................................................ꢁ  
Fault and Warning Conditions........................................................ꢁꢁ-ꢁ3  
Access to the Current Fault or Warning..............................................3  
Viewing the Fault History ....................................................................24  
Viewing Information About the Heater.................................................24  
PRIOR TO START-UP REQUIRED ABILITY...........................................5  
OPERATING INSTRUCTIONS................................................................5  
Adjustment Procedure (Initial Start-Up) .........................................25-26  
Lighting Instructions ............................................................................26  
Cathodic Protection.............................................................................7  
Precautions .........................................................................................7  
GENERAL INFORMATION......................................................................7  
Power Burner ......................................................................................7  
High Limit ............................................................................................7  
High Altitude Installations....................................................................7  
MAINTENANCE ......................................................................................7  
General ...............................................................................................7  
Maintenance Schedule........................................................................7  
Flushing...............................................................................................8  
Draining...............................................................................................8  
Sediment Removal..............................................................................8  
Lime Scale Removal ......................................................................ꢁ8-ꢁ9  
Powered Anode System......................................................................9  
Drain Valve and Access Panels ..........................................................9  
Relief Valve .........................................................................................9  
Vent System........................................................................................9  
INSTALLATION DIAGRAMS ..............................................................30-34  
Multiple Unit Installations ....................................................................35  
CHECKLIST AND SERVICE INFORMATION .........................................36  
Burner Operational Problems..............................................................36  
Not Enough or No Hot Water ..............................................................36  
Water Is Too Hot..................................................................................36  
Water Heater Makes Sounds..............................................................36  
Water Leakage is Suspected...................................................................36  
TROUBLESHOOTING .......................................................................36-38  
REPLACEMENT PARTS.........................................................................38  
LIMITED WARRANTY.............................................................................39  
FEATURES  
DANGER  
THIS WATER HEATER IS EQUIPPED WITH AN ADJUSTABLE  
THERMOSTAT TO CONTROL WATER TEMPERATURE. HOT  
WATER TEMPERATURES REQUIRED FOR AUTOMATIC  
DISHWASHER AND LAUNDRY USE CAN CAUSE SCALD  
BURNS RESULTING IN SERIOUS PERSONAL INJURY AND/OR  
DEATH. THE TEMPERATURE AT WHICH INJURY OCCURS  
VARIES WITH THE PERSON’S AGE AND TIME OF EXPOSURE.  
THE SLOWER RESPONSE TIME OF CHILDREN, AGED OR  
DISABLED PERSONS INCREASES THE HAZARDS TO THEM.  
NEVER ALLOW SMALL CHILDREN TO USE A HOT WATER TAP,  
OR TO DRAW THEIR OWN BATH WATER. NEVER LEAVE A  
CHILD OR DISABLED PERSON UNATTENDED IN A BATHTUB  
OR SHOWER.  
IMPORTANT  
IT IS REQUIRED THAT A QUALIFIED SERVICE TECHNICIAN  
PERFORM THE INITIAL FIRING OF THE HEATER. AT THIS TIME  
THE USER SHOULD NOT HESITATE TO ASK THE TECHNICIAN  
ANY QUESTIONS WHICH HE MAY HAVE IN REGARD TO THE  
OPERATION AND MAINTENANCE OF THE UNIT.  
ACHECKLISTAND SERVICE INFORMATION section are included  
at the rear of this manual. By using this checklist the user may  
be able to make minor operational adjustments and save himself  
unnecessary service calls. However, the user should not attempt  
repairs which are not listed in this section.  
WATER TEMPERATURE CONTROL  
THE WATER HEATER SHOULD BE LOCATED IN AN AREA  
WHERE THE GENERAL PUBLIC DOES NOT HAVE ACCESS TO  
SET TEMPERATURES.  
The water temperature is controlled using the Temperature Control  
Up/Dn Button on the Display at the front of the unit (See Figure 1).  
This control utilizes two temperature probes to determine the tank  
temperature. The primary temperature probe is located at the top  
of the tank and the other is near the water inlet.  
3
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“AT A GLANCE” BTH 300/400/500  
QUICK INSTALLATION TIPS  
Horizontal Sidewall Venting  
Vertical Rooftop Venting  
4
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The temperature may be adjusted from 80°F/27°C to 180°F/82°C. Valves for reducing point-of-use temperature by mixing cold  
The temperature was adjusted to 120°F/49°C before the heater and hot water are available (see Figure 2). Also available are  
was shipped from the factory. It is recommended that lower water inexpensive devices that attach to faucets to limit hot water  
temperatures be used to avoid the risk of scalding. It is further temperatures. Contact a licensed plumber or the local plumbing  
recommended, in all cases, that the water temperature be set for the authority.  
lowest temperature which satisfies your hot water needs. This will  
also provide the most energy efficient operation of the water heater  
and minimize scale formation.  
WATER TEMPERATURE SETPOINT ADJUSTMENT  
PROCEDURE  
CAUTION  
THE TEMPERATURE OF THE WATER AT THE TANK OUTLET  
MAY NOT CORRESPOND TO THE TEMPERATURE SETPOINT  
PROGRAMMED IN THE CONTROLLER. THE USER CAN EASILY  
CHANGETHETEMPERATURESETPOINTATANYTIMEBYUSING  
THE FOLLOWING PROCEDURE. INALL CASES, INPUT POWER  
MUST BE APPLIED TO THE CONTROLLER TO PERFORM ANY  
PROGRAMMING OPERATIONS.  
TheOperating Set Point of this water heater determines the regulated  
temperature for the water in the tank. This parameter is adjusted in the  
Temperature menu. Items in this menu allow you to monitor different  
temperature readings in the tank along with adjusting the Operating  
Set Point and Differential. To change the current programmed  
temperature setpoint value, see OPERATION section for details.  
FIGURE 2.  
Figure 1 shows the approximate time-to-burn relationship for normal  
adult skin. Short repeated heating cycles caused by small hot water  
uses can cause temperatures at the point of use to exceed the  
HIGH LIMIT SWITCH (E.C.O.)  
thermostat setting by up to 20°F (11C°). If you experience this type  
of use, you should consider using lower temperature settings to  
reduce scald hazards.  
The top immersion well of the dual bulb controller also contains the  
high limit (energy cutoff) sensor. The high limit switch interrupts  
the main burner gas flow should the water temperature reach  
approximately 202°F/94°C. Should the high limit switch activate,  
the water temperature must drop below 140°F/60°C before the  
controller can be reset. The following is a possible reason for high  
limit switch operation.  
A malfunction in the thermostatic controls would allow the gas  
valve to remain open causing water temperature to exceed the  
thermostat setting. The water temperature would continue to rise  
until high limit switch operation.  
Contact your dealer or servicer if continued high limit switch  
operation occurs.  
DISHWASHING MACHINE REQUIREMENT  
All dishwashing machines meeting the National Sanitation  
Foundation requirements are designed to operate with water flow  
pressures between 15 and 25 pounds per square inch (103 Kpa  
and 173 Kpa). Flow pressures above 25 pounds per square inch  
(173 Kpa), or below 15 pounds per square inch (103 Kpa), will result  
in improperly sanitized dishes. Where pressures are high, a water  
pressure reducing or flow regulating control valve should be used  
in the 180°F (82°C) line to the dishwashing machine, and should be  
adjusted to deliver water between these limits.  
Temperature  
Setting  
Time to Produce 2nd & 3rd  
Degree Burns on Adult Skin  
Nearly instantaneous  
Nearly instantaneous  
About 1/2 second  
180°F/82°C  
170°F/77°C  
160°F/71°C  
150°F/66°C  
140°F/60°C  
130°F/54°C  
120°F/49°C  
The National Sanitation Foundation also recommends circulation of  
180°F (82°C) water. Where this is done, the circulation should be  
very gentle so that it does not cause any unnecessary turbulence  
inside the water heater. The circulation should be just enough to  
provide 180°F (82°C) water at the point of take-off to the dishwashing  
machine. Adjust flow by means of the plug cock in the circulating  
line. (See installation diagrams.)  
About 1-1/2 seconds  
Less than 5 seconds  
About 30 seconds  
More than 5 minutes  
FIGURE 1.  
5
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THE HEATER SHALLBE LOCATED OR PROTECTED SO ITIS NOT  
SUBJECT TO PHYSICAL DAMAGE BY A MOVING VEHICLE.  
CIRCULATING PUMP  
Acirculating pump is used when a system requires a circulating loop or  
there is a storage tank used in conjunction with the heater. Refer to the  
piping diagrams at rear of manual for electrical hookup information and  
install in accordance with the current edition of the National Electrical  
Code, NFPA 70 or the Canadian Electrical Code, CSA C22.1.  
DO NOT LOCATE THE HEATER WHERE NOISE FROM THE  
EXHAUST OR INTAKE WILL BE OBJECTIONABLE. THIS  
INCLUDES LOCATIONS CLOSE TO OR ACROSS FROM  
WINDOWS AND DOORS. AVOID ANCHORING THE VENT AND  
INTAKE PIPES DIRECTLY TO FRAMED WALLS, FLOORS OF  
CEILINGS UNLESS RUBBER ISOLATION PIPE HANGERS  
ARE USED. THIS PREVENTS ANY VIBRATIONS FROM BEING  
TRANSMITTED INTO THE LIVING SPACES.  
All bronze circulators are recommended for used with commercial  
water heaters.  
Although circulators are oiled and operated by the manufacturer  
some circulators must be oiled again before operated. Please refer  
to manufacturer's instructions.  
WARNING  
FLAMMABLE ITEMS, PRESSURIZED CONTAINERS OR ANY  
OTHER POTENTIAL FIRE HAZARDOUS ARTICLES MUST  
NEVER BE PLACED ON ORADJACENT TO THE HEATER. OPEN  
CONTAINERS OF FLAMMABLE MATERIAL SHOULD NOT BE  
STORED OR USED IN THE SAME ROOM WITH THE HEATER.  
INSTALLATION INSTRUCTIONS  
REQUIRED ABILITY  
When installing the heater, consideration must be given to  
proper location. Location selected should be as close to the  
intake and exhaust termination points as practicable, with  
adequate air supply and as centralized with the piping system  
as possible.  
INSTALLATION OR SERVICE OF THIS WATER HEATER  
REQUIRES ABILITY EQUIVALENT TO THAT OF A LICENSED  
TRADESMAN IN THE FIELD INVOLVED. PLUMBING, AIR  
SUPPLY, VENTING, GAS SUPPLY AND ELECTRICAL WORK  
ARE REQUIRED.  
THE HEATER MUST NOT BE LOCATED IN AN AREA WHERE IT  
WILL BE SUBJECT TO FREEZING.  
INSULATION BLANKETS  
Insulation blankets available to the general public for external use  
on gas water heaters are not approved for use on your A.O. Smith  
water heater. The purpose of an insulation blanket is to reduce the  
standby heat loss encountered with storage tank water heaters.  
Your A.O. Smith water heater meets or exceeds the ASHRAE/IES  
90.1-1999 standards with respect to insulation and standby loss  
requirements, making an insulation blanket unnecessary.  
LOCATE IT NEAR A FLOOR DRAIN. THE HEATER SHOULD  
BE LOCATED IN AN AREA WHERE LEAKAGE FROM THE  
HEATER OR CONNECTIONS WILL NOT RESULT IN DAMAGE  
TO THE ADJACENT AREA OR TO LOWER FLOORS OF THE  
STRUCTURE.  
When such locations cannot be avoided, it is recommended that  
a suitable drain pan, adequately drained, be installed under the  
appliance.  
WARNING  
Should you choose to apply an insulation blanket to this heater, you  
should follow these instructions. Failure to follow these instructions  
can result in fire, asphyxiation, serious personal injury or death.  
WARNING  
THIS WATER HEATER ISACONDENSING UNITAND REQUIRES  
A DRAIN TO BE LOCATED IN CLOSE PROXIMITY TO ALLOW  
THE CONDENSATE TO DRAIN SAFELY. THE CONDENSATE  
DRAINS FROM THE UNIT AT THE EXHAUST ELBOW LOCATED  
AT THE BOTTOM OF THE UNIT. NOTE: IT IS IMPORTANT THAT  
THE CONDENSATE HOSE NOT BE ELEVATED ABOVE THE  
EXHAUST ELBOW (SEE FIGURE 3). THE CONDENSATE BUILD-  
UP WILL BLOCK THE EXHAUST OUTLET, WHICH WILL CAUSE  
IMPROPER OPERATION.  
Do not apply insulation to the top, or the upper 15" (38 cm) of the  
water heater, as this will interfere with safe operation.  
Do not cover the temperature & pressure relief valve.  
Do not cover the instruction manual. Keep it on the side of the  
water heater or nearby for future reference.  
Do obtain new labels fromA.O. Smith for placement on the blanket  
directly over the existing labels.  
LOCATING THE HEATER  
WARNING  
THERE IS A RISK IN USING FUEL BURNING APPLIANCES  
SUCH AS GAS WATER HEATERS IN ROOMS, GARAGES OR  
OTHER AREAS WHERE GASOLINE, OTHER FLAMMABLE  
LIQUIDS OR ENGINE DRIVEN EQUIPMENT OR VEHICLESARE  
STORED, OPERATED OR REPAIRED. FLAMMABLE VAPORS  
ARE HEAVY AND TRAVEL ALONG THE FLOOR AND MAY BE  
IGNITED BY THE HEATER’S IGNITER OR MAIN BURNER  
FLAMES CAUSING FIRE OR EXPLOSION. SOME LOCALCODES  
PERMIT OPERATION OF GAS APPLIANCES IF INSTALLED  
18 INCHES (46 cm) OR MORE ABOVE THE FLOOR. THIS  
MAY REDUCE THE RISK IF LOCATION IN SUCH AN AREA  
CANNOT BE AVOIDED.  
FIGURE 3.  
WARNING  
DO NOT USE THIS APPLIANCE IF ANY PART HAS BEEN  
UNDER WATER. IMMEDIATELY CALL A QUALIFIED SERVICE  
TECHNICIAN TO INSPECT THE APPLIANCE AND TO REPLACE  
ANY PART OF THE CONTROLSYSTEMANDANY GAS CONTROL  
WHICH HAS BEEN UNDER WATER.  
6
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