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GAS-FIRED POWER BURNER COPPER BOILERS
FOR HYDRONIC HEATING AND HOT WATER SUPPLY
• INSTALLATION • OPERATION • MAINTENANCE • 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:
• 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.
TEXT IN BLACK BOLD TYPE OR UNDERLINED CONTAINS
INFORMATION RELATIVE TO YOUR SAFETY. PLEASE
READ THOROUGHLY BEFORE INSTALLING AND USING
THIS APPLIANCE.
PRINTED IN U.S.A. 1004
H
CAUTION
PLACE THESE INSTRUCTIONS ADJACENT TO BOILER AND
NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE
MODELS:
LB/LW-500, 750 AND 1000
SERIES 400/401
A DIVISION OF A.O. SMITH CORPORATION
McBEE, SC RENTON, WA STRATFORD, ONTARIO
VELDHOVEN, THE NETHERLANDS
www.aosmithwaterheaters.com
1
PART NO. 212107-000 REV. 00
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Table of Contents
Summary of Contents for Legend LB 500
- Page 1 MODELS: LB/LW-500, 750 AND 1000 SERIES 400/401 GAS-FIRED POWER BURNER COPPER BOILERS FOR HYDRONIC HEATING AND HOT WATER SUPPLY • INSTALLATION • OPERATION • MAINTENANCE • 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.
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Page 2: Rough-In Dimensions
ROUGH-IN DIMENSIONS Minimum clearances to combustibles: • 4” (102 mm) rear • 0” (0 mm) top & sides • 6” (152 mm) vent TABLE 1, GAS AND ELECTRICAL CHARACTERISTICS Manifold Pressure Maximum Supply Pressure Electrical Characteristics Model Type of Gas Inches W.C. - Page 3 2” NPT Propane The ideal flow rate through the Legend models is considered to be the flow rate that results in a 20 F° temperature rise across the unit. Table 4, shows head loss through units at flow rate resulting in 20 F° rise. For head loss at other flow rates see sheet E202.2 in...
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Page 4: Table Of Contents
CONTENTS Page Page ROUGH-IN DIMENSIONS .............. 2-3 Hot Water Heating (Hydronic) Equipment ......... 16 FOREWORD .................. 4 Internal Contaminants ............. 17 Grounding Instructions ............. 5 Hot Water Supply System General Water Line Connections ..17 Inlet Water Considerations ............5 Hard Water Conditions ............ -
Page 5: Grounding Instructions
Products Company. When ordering, be sure to state the model number and the altitude of the location where the boiler is installed. PRECAUTIONS TABLE 5. LEGEND 2000 ORIFICE TABLE IF THE UNIT IS EXPOSED TO THE FOLLOWING, DO NOT OPERATE Natural Gas... -
Page 6: Field Installed Components
FEATURES/CONTROLS strengthen the igniter, it is still fragile and care must be taken in handling the igniter to prevent breakage. The Legend 2000 ® is a low-pressure boiler (Category IV) to be used as either hot water supply (domestic/commercial water heating) or hot water heating (hydronic) application. -
Page 7: Blower Prover Switch
AIR SHUTTER the BFS, the main burner is extinguished (if boiler is running) or the boiler will not start up. The blower is equipped with an air shutter assembly for fine adjustment of the air to gas ratio The assembly consists of a BLOWER PROVER SWITCH shutter flange and the air shutter. -
Page 8: Circulating Pump
Your local code authority may have other specific safety relief field. valve requirements not covered below. NOTE: If a system pump is to be installed on a Legend LB model, the maximum rating of the pump motor must WARNING not exceed 1 hp. -
Page 9: Installation Instructions
If the boiler is installed above radiation level, a Low Water Cutoff The T & P relief valve must comply with the applicable construction Device must be installed in the boiler outlet at the time of provisions of the Standard for Relief Valves and Automatic Gas installation. -
Page 10: Venting
SPECIAL INSTALLATION CONSIDERATIONS B. CANADIAN INSTALLATIONS The Legend 2000 ® is listed as a Category IV appliance and utilizes Ventilation of the space occupied by the boiler(s) shall be provided a mechanical forced draft system. -
Page 11: Venting System Using Al 29-4C
9. The venting system in a multi-family structure must be planned • When multiple Legend boilers are connected using a com- to be enclosed when passing through occupied or unoccupied mon power venter and common power venter and common spaces above the connected boiler. - Page 12 NOTES: If the exhaust vent terminal is within 10’ (3.0 m) of a wall or parapet, it must extend a minimum of 2’ (610 mm) above the wall or parapet. Joints are not joined to show vent pipe orientation. FIGURE 9. VERTICAL TERMINATION NOTES: Joints are not joined to show vent pipe orientation.
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Page 13: Venting Supports
The Boot-Tee Drain Cover is required in order to dispose of DO NOT rivet or screw the straps to the conduit or otherwise puncture the conduit wall. Instead, wrap an extra loop of strap the condensate from the venting system. The plastic tube around the conduit to hold it in position, or attach the strap to (3/8 [9 mm] ID, 10 feet [3 m] long) needed to route the condensate the center screw of the double wall AL 29-4C... - Page 14 NOTE: Joints are not joined to show vent pipe orientation. FIGURE 11. DIRECT VENT HORIZONTAL CAUTION Direct venting into dead air spaces such as; alleys, atriums and inside corners can cause recirculation 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.
- Page 15 Option B (Figures 11B & 11C) assures no recirculation of flue gases. 90 EQUIVALENT FEET (27.4M) OF VENTING (MAX.) AL 29-4C AIR INTAKE TERMINAL HORIZONTAL AIR INTAKE NOTES: PVC PIPE 90 • IF THE EXHAUST VENT TERMINAL IS WITHIN 10’ (3.0M) EQUIVALENT FEET (27.4M) OF A WALL OR A PARAPET, IT MIUST EXTEND A MINIMUM OF 2’...
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Page 16: Direct Vent Installation Requirements
TWT shall not be greater than ninety (90) equivalent feet Figure 12 shows a typical primary, secondary piping method. [27.4 m] of vent pipe nor less than nine (9) feet [3 m] (excluding This is the preferred piping method for most copper fin tube fittings) unless the vent is through a non-combustible wall. -
Page 17: Internal Contaminants
NOT provided and must be field-installed. It is essential that all water piping be installed and connected as NOTE: If a system pump is to be installed on a Legend LB shown on the diagrams. Check the diagrams to be used... - Page 18 ONE LEGEND (MODEL LW) HOT WATER SUPPLY BOILER WITH VERTICAL TANK DANGER TEMPERATURE SETTING SHOULD NOT EXCEED SAFE USE TEMPERATURE AT FIXTURES. SEE WATER TEMPERATURE CONTROL WARNING ON PAGE 28. IF HIGHER PREHEAT TEMPERATURES ARE NECESSARY TO OBTAIN ADEQUATE BOOSTER OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT WATER SUPPLIED TO FIXTURES.
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Page 19: Hard Water Conditions
HARD WATER CONDITIONS TANK PROBE SET-POINT ADJUSTMENT Where hard water conditions exist, water softening or the threshold When the temperature sensor is installed in a water tank, and type of water treatment is recommended. This will protect the the sensor is used with the WHC1502 system, the controller will monitor and control the temperature of the water at the sensor dishwashers, coffee urns, water heaters, water piping and other location. -
Page 20: Gas Supply Line Sizing
Size of gas supply piping may be larger than heater connection on installations where a significant run of piping is required. To prevent damage, care must be taken not to apply too much torque when attaching gas supply pipe to boiler gas inlet. Fittings and unions in the gas line must be of the metal to metal type. -
Page 23: Schematic Diagram
FIGURE 17 - SCHEMATIC DIAGRAM... -
Page 24: Operation
PURGING SHOULD BE PERFORMED BY PERSONS EXPERIENCED IN THIS TYPE OF GAS SERVICE TO AVOID RISK OF FIRE OR NOTE: If a system pump is to be installed on a Legend LB model, EXPLOSION. PURGE DISCHARGE MUST NOT ENTER CONFINED the maximum rating of the pump motor must not exceed 1 hp. -
Page 25: Lighting & Operating Instructions
LIGHTING & OPERATION INSTRUCTIONS FOR MODELS LB/LW-500 ONLY: FOR YOUR SAFETY READ BEFORE OPERATING WARNING: IF YOU DO NOT FOLLOW THESE INSTRUCTIONS EXACTLY, A FIRE OR EXPLOSION MAY RESULT CAUSING PROPERTY DAMAGE, PERSONAL INJURY OR LOSS OF LIFE. A. THIS APPLIANCE DOES NOT HAVE A PILOT. IT IS C. - Page 26 LIGHTING & OPERATION INSTRUCTIONS FOR MODELS LB/LW-750 AND 1000 ONLY: FOR YOUR SAFETY READ BEFORE OPERATING WARNING: IF YOU DO NOT FOLLOW THESE INSTRUCTIONS EXACTLY, A FIRE OR EXPLOSION MAY RESULT CAUSING PROPERTY DAMAGE, PERSONAL INJURY OR LOSS OF LIFE. A.
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Page 27: Inlet Gas Pressure
in the combustion chamber to clear. IF YOU DETECT GAS ODOR maintained when all gas appliances connected to the system AT THE END OF THIS PERIOD DO NOT PROCEED WITH LIGHTING. are operating simultaneously and at full fire supply. Pressure RECOGNIZE THAT GAS EVEN IF IT SEEMS WEAK, MAY INDICATE drops of more than 1/2”... -
Page 28: Water Temperature Regulation
FOR LB/LW-750 AND LB/LW-1000 MODELS: energy efficient operation of the boiler and minimize scale formation in the heat exchanger, thus prolonging the life of the 1. Manually shut off the gas supply by one of the two methods. boiler. On boilers that have a manual shutoff valve downstream from the automatic gas valves, turn the manual shut off valve to the SETTING THE WATER HEATER TEMPERATURE AT 120°F (49°C) “OFF”... -
Page 29: Maintenance
every six months. All relief valves should be inspected and 2. If the ignition control determines the actual water temperature manually operated at least twice a year. at the outlet temperature sensing probe is below the programmed temperature set-point less the switching VENTING MAINTENANCE differential, and the thermostat circuit is closed, a call for heat is activated. -
Page 30: Burner Maintenance
Flame pattern should have hard, uniform blue flames surrounding 9. Restore electrical power and gas supply to the boiler. the burner, see figure 19. • Put the boiler back in operation by following the Lighting If the flame is pulsing, floating, yellow and/or lifting off the burner, and Operating instructions in this manual. -
Page 31: Line Polarity Indicator
24-Volt method of temperature control, the J33 jumper must be removed and the red/green wires in the junction box at the rear of the unit must be used. (see figure 21 and 22). Standard LB models will not have a jumper across the J33 board leads. Wires are provided in the junction box for a 24-Volt method of temperature control. -
Page 32: Temperature Set-Point Adjustment Procedure
If the ADJUST push-button is held down long enough, the set- Options/Features Setting Procedures: • Set Appliance Temperature Set-Point Value point will reach 110°F [43°C], the minimum value (or 240°F [115°C], • Set Appliance Switching Differential Value the maximum value) and stop. At this point, if the desired setting •... -
Page 33: Display Current Mode
Table 10. value (or 50°F [28°C], the maximum value) and stop. At this point, if the desired switching differential is not obtained, release the Display Message Appliance Mode ADJUST push-button and depress it again. The switching IdLe Idle state differential value will now start at 5°F (3°C) to (50°F [28°C]) and NoSn Wait for No Sensor Inputs once again increase (decrease) in value for as long as the ADJUST... -
Page 34: Display Board Led Indicators
If the ADJUST push-button is held down long enough, the TROUBLESHOOTING set-point will reach 110°F (43°C), the minimum value (or 190°F [88°C], the maximum value) and stop. At this point, if the desired set-point is not obtained, release the ADJUST push-button and SHORTCYCLING depress it again. - Page 35 210°F (99°C) for such applications. IMPORTANT NOTES If you experience trouble with your Legend unit, the best advice is – The unit has an adjustable Set-Pt Differential. The tank Probe’s to start at the main power source and work forward. Here are Set-Pt Differential is not adjustable and is fixed at 5°F (3°C).
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Page 36: Limited Warranty
LIMITED WARRANTY A. O. Smith Corporation, the warrantor, extends the following LIMITED WARRANTY to the owner of this boiler: 1. If within TEN years after initial installation of the boiler, a coiled heat exchanger or gas burner shall prove upon examination by the warrantor to be defective in material or workmanship, the warrantor, at his option will exchange or repair such part or portion.
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