Operational Problems; Rough Starting, Rough Operation; Momentary Ignition; Not Enough Or No Hot Water - A.O. Smith 300 Series 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 technician should perform any service procedures on the
water heater.
Note: For technical support or to locate a qualified service technician
in your area, call the phone number on the warranty sheet
supplied with this water heater.

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
technician 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 intake air screen(s).
•
Clogged/blocked the Main Burner.
•

MOMENTARY IGNITION

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 intake air screen(s).
•
Clogged/blocked Main Burner.
•

NOT ENOUGH OR NO HOT WATER

No power to the water heater, check breaker, fuses.
•
Enable/Disable switch in "disabled" position. Set to enable to
•
allow unit to operate.
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 is 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 improperly set.
•
If installed check Thermostatic Mixing Valve settings.
•
Lime build-up on temperature probe. Inspect and clean.
•

NOISY OPERATION

Normal operating noise of electrical components; Combustion
•
Blower, transformer hum, relay contact closure.
60
CAUTION