A.O. Smith BTR 151 THRU 201/A warranty Sequence of Operation

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OPERATION

IMPORTANT

A qualified person must perform the initial firing of the heater. At this time the user should not hesitate to ask the individual any questions which they may have in regard to the operation and maintenance of the unit.

An Operational Checklist is included at the rear of this manual. By using this checklist the user may be able to make minor operational adjustments and avoid unnecessary service calls. However, the user should not attempt repairs which are not listed under the USER column.

GENERAL

NEVER OPERATE THE HEATER WITHOUT FIRST BEING CERTAIN IT IS FILLED WITH WATER AND A TEMPERATURE AND PRESSURE RELIEF VALVE IS INSTALLED IN THE RELIEF VALVE OPENING OF THE HEATER.

SHOULD OVERHEATING OCCUR OR THE GAS SUPPLY FAIL TO SHUT OFF, TURN OFF THE MANUAL GAS CONTROL VALVE TO THE APPLIANCE.

CAUTION

Before proceeding with the operation of the unit make sure the water heater and system are filled with water and all air is expelled.

FILLING

1.Close the heater drain valve by turning handle clockwise.

2.Open a nearby hot water faucet to permit the air in the system to escape.

3.Fully open the cold water inlet pipe valve allowing the heater and piping to be filled.

4.Close the hot water faucet as water starts to flow.

5.The heater is ready to be operated.

WARNING

THE GAS VALVE MUST HAVE BEEN IN THE OFF POSITION FOR AT LEAST 5 MINUTES. This waiting period is an important safety step. Its purpose is to permit gas that may have accumulated in the combustion chamber to clear. IF YOU DETECT GAS ODOR AT THE END OF THIS PERIOD DO NOT PROCEED WITH LIGHTING. RECOGNIZE THAT GAS EVEN IF IT SEEMS WEAK, MAY INDICATE PRESENCE OFACCUMULATED GAS SOMEPLACE IN THE AREA WITH RISK OF FIRE OR EXPLOSION. SEE THE FRONT PAGE FOR STEPS TO BE TAKEN.

All gas and water lines leak tested and open.

Read SEQUENCE OF OPERATION section of this manual prior to lighting and operating this appliance.

With above conditions satisfied, start the unit in accordance with the instructions on the Operating label attached to the heater. If label instructions are not legible - determine which gas valve the appliance is equipped with and use the applicable OPERATING INSTRUCTIONS as follows:

Each heater is equipped with an ignition control board. The controller will try three times to light the main burner before going

into lockout. After the controller tries three times, it will wait one hour before trying to light the unit again. This cycle will continue until the main burners are ignited or the unit is shut down.

ADJUSTMENTS

ON INITIAL STARTUP SOMEADJUSTMENTS ARE NECESSARY.

1.CHECK MANIFOLD AND INLET GAS PRESSURES.

2.CYCLECHECK-CHECKATLEASTONEBURNEROPERATION - WHEN THERMOSTAT IS SATISFIED, BURNER WILL SHUT OFF AND INDUCER WILL STOP RUNNING. ON CALL FOR HEAT - THE INDUCER WILL COME ON AND CLOSE THE PRESSURE SWITCH AND THE IGNITION SEQUENCE DESCRIBED ABOVE WILL BEGIN, SEE “SEQUENCE OF OPERATION”.

SEQUENCE OF OPERATION

The following information will describe the Sequence of Operation for this appliance.

1.Switch power on to unit.

2.Thermostat calls for heat.

3.Ignition Control Board performs diagnostic check on system components.

4.On completion of diagnostics check, the Ignition Control Board sends signal to Exhaust Inducer.

5.Exhaust Inducer begins drawing air through appliance closing the Prover Switch.

6.On completion of Prover Switch engagement, the Ignition Control Board begins the ignition cycle.

7.The Ignition Control Board provides power to the Silicon Nitride Ignitor.

8.The Silicon Nitride Ignitor heats up for approximately 17 to 20 seconds.

9.At the end of Silicon Nitride Ignitor’s warm-up, the Ignition Control Board opens the Gas Valve.

10.From the time the Gas Valve opens, the Ignition Control Board waits 3 seconds and then shuts off power to the Silicon Nitride Ignitor.

11.From the time the Silicon Nitride Ignitor’s power is shut off, the Ignition Control Board waits 3 more seconds to monitor the Flame Sensor.

12.If the Flame Sensor does not detect a strong enough flame, the Ignition Control Board shuts off the Gas Valve and allows the Exhaust Inducer to purge the unit for 20 seconds. At that time, the Ignition Control Board restarts with step 7. It will try and ignite the main burners 2 more times. If the unit does not light, the Ignition Control Board will wait one hour and then restart at step 3. This cycle will continue until the unit lights or the power is shutoff to the unit.

13.If the Flame Sensor detects a strong flame, the Ignition Control Board will allow the unit to operate until the thermostat is satisfied.

14.Once the unit is satisfied, the Ignition Control Board will shut off the Gas Valve and the unit will be in standby mode until another call for heat is initiated by the thermostat.

See the flow chart on page 25 for more information.

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Contents Placetheseinstructionsadjacenttoheater AndnotifyownertokeepforfuturereferenceDivision of A. O. Smith Corporation Foreword ROUGH-IN-DIMENSIONSRecovery Rating Capacities GPH AT Temperature Rise Shown Heater Performance DataTable of Contents Extended NON-USE Periods FeaturesHigh Altitude Installations Insulation BlanketsElectronic Ignition Control High Limit SwitchExhaust Inducer Blower Assembly Circulating PumpLocating the Heater Required AbilityUncrating LevelingVenting To the Heater and Risk of Fire or Explosion UnconfinedspaceConfinedspace Water Potable Heating Space Heating Multiple Heater ManifoldWater Line Connections Relief ValveGAS Pressure Regulator GAS PipingPurging Length Nominal Iron Pipe Sizes Inches FeetHeater Wiring Single Unit Wiring DiagramInstallation Diagrams GeneralVertical Storage Tank and Forced Circulation Horizontal Storage Tank and Forced CirculationPage Installation DIAGRAMS-SIDE INLET/OUTLET Usage Circulating Return Line ConnectionHeater with Mixing Valve and Recirculated Sanitizing Loop TWO PRE-HEATERS with Booster Heater Horizontal Storage Tank Operation Sequence of OperationFor Your Safety Read Before Operating What to do if YOU Smell GASCheck the Ignitor Assembly Preventive MaintenanceWater Temperature Control Ignitor AssemblyChecking the Input Remote Storage Tank Temperature ControlGAS Valves Venting SystemFlushing HOT Water OdorAnode ROD Inspection DrainingTank Cleanout Procedure Deliming Using FLO-JUG MethodDeliming Solvents System Diagnostics ServiceReplacement Parts Ignition Module SystemSequence of Operation Flow Chart YESOperational Checklist Complaint Cause User ServicemanRemedy Keepthiswarrantypostedadjacenttotheheaterforfuturereference ServiceandrepairexpensesClaimprocedure TankSmith Water Products Company