Operational Problems; Rough Starting, Rough Operation; Momentary Ignition; Not Enough Or No Hot Water - A.O. Smith Gas Models Instruction Manual

operatIonal probleMs

Read and understand this instruction
manual and the safety messages
herein before installing, operating or
servicing this water heater.
Failure to follow these instructions and
safety messages could result in death
or serious injury.
This manual must remain with the
water heater.
This section of the manual is intended to be an aid in correcting
common operational problems, it is not all inclusive. The installer
may be able to observe and correct certain problems which might
arise when the water heater is first put into operation or when it is
re-fired after a prolonged shutdown. However, only qualified service
agents should perform any service procedures on the water heater.
note: Call the technical support phone number listed on the back
cover of this manual for further technical assistance or to locate a
qualified service agent in your area.

rouGh startInG, rouGh operatIon

Fire and Explosion Hazard
Do not use water heater with any gas
other than the gas shown on the rating
plate.
Excessive gas pressure to gas valve can
cause serious injury or death.
Turn off gas lines during installation.
Contact a qualified installer or service
agency for installation and service.
• Undersized supply gas line (low volume of supply gas).
• Low Gas Pressure.
• Excessive supply gas pressure.
• Excessive manifold (offset) gas pressure.
• Incorrect Fuel Type
• Vent (exhaust) gas recirculation at the vent and intake air pipe
terminations on Direct Vent installations.
• Excessive equivalent lengths of intake air and/or vent (exhaust)
piping installed.
• Clogged/blocked wire screen(s).
• Clogged/blocked Main Burner.

MoMentarY IGnItIon

CAUTION
Burn Hazard
•
The combustion chamber and burner sleeve
and housing become very hot during operation.
•
Do not reach into the burner housing or
combustion chamber if the water heater
is still hot.
•
Allow the water heater to cool and always use
gloves when handling the main burner.
If the Main Burner ignites momentarily but does not sustain ignition
allow the water heater to try to ignite up to two more times until
control system locks out and the Ignition Failure Fault message
is displayed on the control system's LCD. If the water heater is
experiencing rough starts - see Rough Starting, Rough Operation
on this page. For momentary ignition problems without rough
starting check the following:
• Incorrect manifold (offset) gas pressure.
• Undersized supply gas line (low volume of supply gas).
• Low Gas Pressure
• See the list of possible causes and things to check and repair
for the Ignition Failure Fault message.
• Clogged/blocked wire screen(s).
• Clogged/blocked Main Burner.

not enouGh or no hot water

• No power to the water heater, check breaker, fuses and the
water heater on/off switch.
• Hot water supply valve(s) to fixtures closed.
• Operating Set Point is set too low, Differential setting is set too
high.
• Temperature Probe Offset setting are causing the heating cycles
to terminate prematurely.
• The heating capacity of the water heater has been exceeded,
the water heater is unable to meet demand.
• Colder incoming water temperature lengthening the time
required to heat water to desired temperature.
• Hot water piping leaks, open faucets, water heater drain valve
leaking or open.
• Sediment or lime scale accumulation may be affecting water
heater operation.

water Is too hot

• Operating Set Point is set too high.
• Temperature Probe Offset settings improperly set.

noIsY operatIon

• Normal operating noise of electrical components; Combustion
Blower, transformer hum, relay contact closure.

replaceMent parts

Replacement parts may be ordered from the manufacturer,
authorized service agencies or distributors. When ordering parts
be sure to have the complete water heater Model Number, Serial
Number and Series Number available. This information can be
found on the rating plate affixed to the water heater.
Refer to the parts list for more information or call the parts
department or technical support phone number listed on the back
cover of this manual for further assistance.

fault and alert condItIons

fault condItIons

When the control system declares a Fault condition it will display a
Fault message on the control system's LCD with an exclamation "!"
mark. The control system will lock out and disable heating operation
until the condition is corrected. The water heater must be serviced
by a qualified service agent before operation can be restored.

alert condItIons

When the control system declares an Alert condition it will display
an Alert message on the control system's LCD with a question "?"
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