A.O. Smith Water Heater - Manual (Page 25)

Temperature and Pressure Relief Valve
AWARNING
Explosion Harzard
Temperature-pressure relief
valve must comply with ANSI
Z21.22-CSA4.4 and ASME
code.
Properly sized temperature-
pressure relief valve must be
installed in opening provided.
Can result in overheating
and excessive tank pressure.
Can cause serious injury or
death.
Manually operate the temperature and pressure relief
valve at least once a year to make sure it is working
properly. To prevent water damage, the valve must be
properly connected to a discharge line which terminates at
an adequate drain. Standing clear of the outlet (discharged
water may be hot), slowly lift and release the lever handle
on the temperature and pressure relief valve to allow the
valve to operate freely and return to its closed position.
See Figure 21. If the valve fails to completely reset and
continues to release water, immediately shut off the
manual gas control valve and the cold water inlet valve
and call a qualified technician.
FIGURE 21.
MAINTENANCE OF YOUR WATER HEATER
Replacement Parts
IMPORTANT: The following maintenance procedures are
for the FVIR System components and should be performed
by a qualified technician.
Replacement parts may be ordered through your plumber
or the local distributor. Parts will be shipped at prevailing
prices and billed accordingly. When ordering replacement
parts, always have the following information ready:
1. model, serial, and product number
2. type of gas
3. item number
4. parts description
See Repair Parts Section for a list of available repair parts.
Removing the Manifold/Burner Assembly
1. Turn off the gas supply to the water heater at the manual gas
shut-off valve. This valve is typically located beside the water
heater. Note the position of the shut-off valve in the open/on
position then proceed to turn it off (Figure 3).
2. On the lower front of the water heater locate the gas
control valve/thermostat (see Figure 23). Before per­
forming any maintenance, it is important to turn the
temperature dial on the gas control valve/thermostat to
its lowest setting.
3. On top of the gas control valve/thermostat turn the gas
control knob to the “OFF” position. NOTE: On the Rob­
ertshaw gas control valve/thermostat the dial stop must
first be depressed before turning the gas control knob
(Figure 19).
WHITE RODGERS GAS VALVE
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THERMOCOUPLE
MANIFOLD TUBE
ROBERTSHAW GAS VALVE
THERMOCOUPLE L
MANIFOLD TUBE
FIGURE 22.
4.
5.
Remove the outer door.
Remove the two screws securing the manifold door
assembly to the combustion chamber (Figure 23).
GAS CONTROL VALVE/
THERMOSTAT
6. Disconnect the thermocouple (right-hand thread), pilot
tube, the igniter wire from the igniter button, the two
connectors attached to the thermal switch, and manifold
tube at the gas control valve/thermostat. (Figures 22
& 23.) NOTE: L.P. Gas systems use reverse (left-hand)
threads on the manifold tube.
7. Grasp the manifold tube and push down slightly to free the
manifold, pilot tube, and thermocouple.
8. Carefully remove the manifold/burner assembly from the
burner compartment. NOTE: Be sure not to damage
internal parts.
Removing the Burner from the Manifold/
Burner Assembly
Natural Gas (Low Nox) & L.P. Gas Burner
1. Take off the burner by removing the two (2) screws lo­
cated underneath the burner.
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