Maintenance; Check The Igniter Assembly And Main Burners; Igniter Assembly; Main Burner - A.O. Smith BTR 151 Instruction Manual

check the igniter assemBly and main Burners

At least once a year, check the igniter assembly, Figure 24, and
the main burner, Figure 25, for proper operation. Refer to the
following igniter assembly and main burner sections.

igniter assemBly

For access to igniter assembly, unfasten two screws to burner
cover and remove. Locate the burner with the igniter assembly
and remove screw holding burner to manifold. Slide burner out
to access igniter assembly.
Servicing of the igniter assembly includes keeping the igniter free
of lint, scale or any other foreign debris.
figure 24. igniter

main Burner

The main burner, Figure 25, should display the following
characteristics:
• Cause rapid ignition and carry across entire burner.
• Give reasonably quiet operation during ignition, burning, and
extinction.
• Cause no excessive lifting of flame from burner ports.
figure 25.
If the preceding burner characteristics are not evident, check for
accumulation of lint, scale or other foreign debris that restricts or
blocks the air openings to the burner or heater.
nOTE:
1. Remove main burners from unit.
2. Check that burner venturi and ports are free of foreign debris.
3. Clean burners with bristle brush and/or vacuum cleaner - DO
nOT distort burner ports or pilot location.
4. Reinstall burners in unit. Make sure front and rear of burners
are installed correctly in burner support brackets.
Also check for good flow of combustion and ventilating air to the
unit. Maintain a clear area around the heater at all times.

Venting system

Examine the venting system every six months for obstructions
and/or deterioration of the vent piping.
Remove all soot or other obstructions from chimney which will
retard free draft.

remote storage tank temperature control

The water temperature in the remote storage tank (if used) is
controlled by the storage tank temperature control. The sensing
element is mounted in the hot water storage tank, see Water
Piping Diagram section.
A change in water temperature in the storage tank lower than
the tank temperature control setting will cause the sensor to
activate the circulating pump. The pump then circulates the water
through the heater where the thermostat senses the drop in water
temperature and activates main burner operation of the appliance.

maintenance

If the storage tank temperature control is out of calibration, replace
with new control.
shoUlD oVERhEATING oCCUR oR ThE GAs sUPPly FAIl
To shUT oFF, TURN oFF ThE MANUAl GAs CoNTRol VAlVE
TO THE APPLIAnCE.

temperature-pressure relief ValVe test

It is recommended that the Temperature-Pressure Relief Valve should
be checked to ensure that it is in operating condition every 6 months.
When checking the Temperature-Pressure Relief Valve operation,
make sure that (1) no one is in front of or around the outlet of the
Temperature-Pressure Relief Valve discharge line, and (2) that the
water discharge will not cause any property damage, as the water
may be extremely hot. use care when operating valve as the valve
may be hot.
To check the relief valve, lift the lever at the end of the valve several
times, see Figure 26. 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 And
Flushing on page 28. Replace the Temperature-Pressure Relief
Valve with a properly rated/sized new one, see Temperature-Pressure
Relief Valve on pages 12-13 for instructions on replacement.
If the Temperature-Pressure Relief Valve on the water heater weeps
or discharges periodically, this 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 on page 12. The Temperature-Pressure Relief Valve is
not intended for the constant relief of thermal expansion.
Temperature-Pressure Relief Valve leakage due to pressure build
up in a closed system that does not have a thermal expansion
tank installed is not covered under the limited warranty. Thermal
expansion tanks must be installed on all closed water systems.
Do NoT PlUG ThE TEMPERATURE-PREssURE RElIEF
VALVE OPEnIng. THIS CAn CAuSE PROPERTY DAMAgE,
SERIOuS InJuRY OR DEATH.
27
Burn hazard.
Hot water discharge.
Keep clear of Temperature-
Pressure Relief Valve
discharge outlet.
figure 26.