Operation; General; Sequence Of Operation - A.O. Smith SBD 30 150 Installation And Operation Manual

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.
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.
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 OF ACCUMULATED
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
CAUTION
WARNING
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 SOME ADJUSTMENTS ARE NECESSARY.
1. CHECK MANIFOLD AND INLET GAS PRESSURES.
2. CYCLE CHECK - CHECK AT LEAST ONE BURNER OPERATION
- 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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