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PILOT AND MAIN BURNER
Check pilot and main burners at least every 12 months for
the proper flame characteristics.
The pilot flame should envelop approximately 10 mm (3/8
inch) of tip of thermocouple.
PREVENTIVE MAINTENANCE
3mm
10 mm
If the pilot flame is too small, then the pilot burner must be
cleaned. The position of the igniter electrode should also
be checked to assure that electrode is approximately 3 mm
(1/8’’) from pilot, see figure 6.
The main burner should exhibit the following characteristics:
· Provide complete combustion of gas.
· Cause rapid ignition and carryover of flame across burners.
· Operate quickly during ignition, burning and extinction.
· Burner flames should be blue and there should be no lifting
of flames from burner ports, figure 7.
Figure 6
If the main burners fail to exhibit above characteristics they
must be cleaned, either by blowing them off with compressed
air or by washing them in soap and water and rinsing.
If it proves necessary to wash the main burner assembly the
following procedure should be used:
1. Turn off the gas supply to the water heater.
2. Disconnect pilot gas tube at the gas valve and unscrew
the gas manifold assembly union nut, where the gas
manifold inlet pipe connects to the gas valve and remove
the gas burner assembly.
3. Wash in soap and water and then rinse.
4. Reassemble - Check for gas leaks after reassembly and
correct as required.
5. Refer to Lighting Procedure to relight the heater.
VENTING
The vent piping and finned heat exchanger should be checked
at least once a year for dust and carbon deposits and
cleaned as necessary.
PRESSURE RELIEF VALVE
At least once a year the pressure relief valve should be
checked to insure that if it is in operating condition.
Before testing the relief valve take necessary precautions
to prevent water damage. Lift the lever on the valve several
times until the valve seats properly and operates freely. Do
not check the relief valve when hot water is being draw and
the main burner is on. Water exiting the valve under these
conditions would be hot.
If the pressure relief valve on the appliance discharges this
is an indication of water pressure above the pressure rating
of the relief valve. If the pressure relief valve continually
discharges on a periodic basis contact the water supplier
or local plumbing inspector on how to correct the situation.
Do not plug the pressure relief valve.
PERIODIC REMOVAL OF LIME DEPOSITS
In hard water areas, depending on frequency of use, the
heater should be checked for accumulation of calcium
carbonate (lime) and delimed, if necessary. Thereafter a
regular schedule, based on initial inspection findings, should
be set up to delime the heater. Delivering instructions are
available from your Bosch dealer.
Figure 7