Piezoelectric Igniter System; Testing The Igniter System; Temperature-Pressure Relief Valve Test; Draining, Refi Lling And Flushing - A.O. Smith DIRECT VENTED GAS MODELS Installation And Operating Manual

Residential gas water heaters
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PIEZOELECTRIC IGNITER SYSTEM

The piezoelectric igniter system consists of the igniter
button, electrode, and wire. The pilot is ignited by an
electric spark generated when the igniter button is pressed
(see Figure 39).
ELECTRODE
WIRE TO ELECTRODE
IGNITER BUTTON
Figure 39

TESTING THE IGNITER SYSTEM

Turn "OFF" the gas to the water heater at the manual gas
shut-off valve. Watch the electrode tip while activating the
igniter. A visible spark should jump from the electrode. To
avoid shock, do not touch the burner or any metal part
on the pilot or pilot assembly. If no spark is visible, check
the wire connections and make sure the electrode is not
broken. Replace the igniter if defective. Dirt and rust on the
pilot or electrode tip can prevent the igniter spark. Wipe
clean with a damp cloth and dry completely. Rust can be
removed from the electrode tip and metal surfaces by
lightly sanding with an emery cloth or fi ne grit sandpaper.

TEMPERATURE-PRESSURE RELIEF VALVE TEST

It is recommended that the temperature-pressure relief
valve be checked to ensure it is in operating condition at
least once a year.
When checking the temperature-pressure relief valve
operation, make sure that (1) no one is in front of or around
the outlet of the T&P valve discharge line, and (2) that
water discharge will not cause any property damage, as
water may be extremely hot. Use care when operating
valve as the valve may be hot.
To check the relief valve, lift lever at the end of valve
several times (see Figure 40). The valve should seat
properly and operate freely.
If after manually operating the valve, it fails to completely
reset and continues to release water, immediately close
the cold water inlet to the water heater and drain the
water heater, see "Draining, Refilling And Flushing"
section. Replace the T&P valve with a properly rated/
sized new one, see "Temperature-Pressure Relief Valve"
for instructions on replacement.
36
THERMOPILE
PILOT
PILOT/
THERMOPILE
BRACKET
www. hotwater .com
Figure 40
If the Temperature-Pressure Relief Valve on the water
heater weeps or discharges periodically, it may be due to
thermal expansion.
Note: Excessive water pressure is the most common
cause of temperature-pressure relief valve leakage.
Excessive water system pressure is most often caused
by "thermal expansion" in a "closed system." See "Closed
Water Systems" and "Thermal Expansion" sections of this
manual. The T&P valve is not intended for the constant
relief of thermal expansion.
DANGER
HOT
HOT
BURN
DRAINING, REFILLING AND FLUSHING
Periodic draining and cleaning of sediment from the tank
maybe necessary. It is recommended that the tank be
drained and fl ushed every 6 months to remove sediment
which may build up during operation. The water heater
should be drained if being shut down during freezing
temperatures or for an extended period of time. See
"Typical Installation" section (Figure 1) in this manual for
location of the water heater components described below.

To Drain The Water Heater Storage Tank

1. Turn the gas control/temperature knob to the "OFF"
position (see Figure 31 and Figure 33).
2. Turn "OFF" the gas supply at the manual gas shut-off
valve.
3. Close the cold water inlet valve to the water heater.
4. Open a nearby hot water faucet and leave open to
allow for draining.
5. Connect a hose to the drain valve and terminate to
an adequate drain.
Note: If the water heater is going to be shut down and
drained for an extended period, the drain valve should be
left open with hose connected allowing water to terminate
to an adequate drain.
6. Open the water heater drain valve.
7. Close the water heater drain valve when all water in
the storage tank has drained.
• Burn hazard.
• Hot water discharge.
• Keep clear of
temperature-pressure
relief valve discharge.

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