Troubleshooting; Replacement Parts - A.O. Smith ***81-140 Installation, Service, Maintenance

Lined tank type gas water heater
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Installation of a second relief valve with lower setting
than the primary relief valve.
An expansion tank of suitable size and pressure rating
and provision to avoid water logging.
HOT WATER ODOR
On occasion, hot water may develop a strong odor. If this occurs,
drain the heater completely, flush thoroughly, and refill. If the
problem persists, chlorination of the heater and replacement of
the factory installed aluminum anodes with magnesium anodes
may correct the condition.
Occasionally water softener companies recommend removal of
heater anodes for odor reasons.
Unauthorized removal of the anode(s) will void the warranty. For
further information contact your dealer.
ANODE ROD MAINTENANCE
The anode rod is used to protect the tank from corrosion. Most
hot water tanks are equipped with an anode rod. The submerged
rod sacrifices itself to protect the tank. Instead of corroding the
tank, water ions attack and eat away the anode rod. This does
not effect the water's taste or color. The rod must be maintained
to keep the tank in operating condition.
Anode deterioration depends on water conductivity, not
necessarily water condition. A corroded or pitted anode rod
indicates high water conductivity and should be checked and/or
replaced more often than an anode rod that appears to be intact.
Replacement of a depleted anode rod can extend the life of your
water heater. Inspection should be conducted by a qualified
technician, and at a minimum should be checked annually after
the warranty period.

TROUBLESHOOTING

Make sure thermostat and operation controls are calling for heat.
Defective wiring or loose connections can simulate the
component defects outlined below. Check associated wiring
before replacing component.
Keep the gas valve control knob in the "OFF" position unless a
run on gas is intended.
Checks must be made in the order outlined below.
MOTOR WILL NOT RUN
Confirm 120V between strip terminals 1 and 2, and 1 and GND.
Check 24V* operating control circuit.
1. Between left terminal T and GND.
• If no voltage, transformer is defective.
• If very low voltage,* circuit is overloaded or transformer is
defective.
2. Between right terminal T and GND.
• If no voltage, circuit between T and T is open.
Check for 120V between motor relay terminal 4 and strip
terminal 2.
• If no voltage, motor relay is defective.
• If voltage present, motor is defective.
MOTOR RUNS IN REPEATED CYCLES –
NO FLAME PRESENT
CAUTION
1. Motor relay drops out due to low voltage.
• Check valve circuit for ground or overload.
MOTOR RUNS CONTINUOUSLY, PREPURGE TIME
ELAPSES, BUT NO FLAME PRESENT
Electric check only (no trial for flame).
Gas valve control knob "OFF".
1. Check for 24V between strip terminal 3 and GND (Models
***81-140 and ***81-199) or between interlock switch terminal
NC, and GRD, on models ***81-270, ***81-370.
Momentarily turn burner switch off to reset control board for each
of the following steps. Tests are valid only during the 5 second
trial for ignition following prepurge as indicated by the neon bulb
located on the control board next to the high voltage coil. To
observe bulb, remove board and cover by removing the Hi Voltage
stud terminal, and remount board.
1. Observe neon bulb during trial for ignition.
• If no glow, control board is defective.
2. Check for 24 V between valve terminals.
• If no voltage, board is defective.
• If no voltage present, valve may be defective.
3. Check for spark at Hi Voltage stud terminal.
• If no spark, board is defective.
4. Check for spark at electrode.
• If no spark, electrode or cable is defective.
Trial for flame. Gas valve control knob "ON". Reset after each
trial.
1. Check that normal gas pressure is available ahead of
automatic gas valve and that gas valve control knob is "ON".
2. During trial for ignition, confirm 24V at valve and check manifold
pressure.
• If no pressure, defective valve confirmed.
• If manifold pressure present, spark electrodes are defective
or misadjusted.
3. Gross air misadjustment. See table 6.
Flame on 5 seconds only.
1. Recheck polarity of 120V supply and that system is grounded
(120V between terminal 1 and GND).
2. Recheck sensor wire and flame electrode.
3. Gross air misadjustment. See table 6.
4. If 1, 2, and 3 OK, board is defective.
*Normal low voltage: Burner in standby - 24V min. Burner
running (gas valve energized) - 21V min.

REPLACEMENT PARTS

Replacement parts may be ordered. Refer to the Yellow Pages
for where to call or contact the contractor or dealer. If for any
reason the installer or dealer fails to provide satisfactory service
you should write the company. When ordering parts be sure to
state the quantity, part number and description of the items
including the complete model and serial number as it appears
on the product. Refer to the parts list for more information.
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***81-199***81-270***81-370

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