A.O. Smith VB-500 - Troubleshooting Gas Valve; Preventative MAINTENANCE; Main Burners

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Thisisapre-mixburnersystem.Theameisnotsupposedtobe
directlyontheburner.Theameshouldbejustabovetheburner
deck approximately 1/8” and blue in color, see illustration.
FIGURE 3. - BURNER FLAMES
Visually check flame characteristics through the view port
located on the top head of the boiler. The “Burner Flames”
illustration shows the normal flame condition.
These boilers are designed to give many years of efficient and
satisfactory service when properly operated and maintained.
To assure continued good performance, the following
recommendations are made.
The area around the unit should be kept clean and free from
lint and debris. Sweeping the floor around the boiler should
be done carefully. This will reduce the dust and dirt which
may enter the burner and heat exchanger, causing improper
combustion and sooting.
MAIN BURNER
Check main burner every three months for proper flame
characteristics. The main burner should display the following
characteristics:
• Providecompletecombustionofgas.
• Causerapidignitionandcarryoverofameacrossentireburner.
• Givereasonablyquietoperationduringinitialignition,operation
and extinction.
•Causenoexcessiveliftingofflamefromburnerports.
If the preceding burner characteristics are not evident, check for
accumulation of lint or other foreign material that restricts or blocks
the air openings to the burner or boiler. To check burners:
1. Shut off all gas and electricity to unit. Allow unit to cool.
2. Remove main burner from unit.
3. Check that burner ports are free of foreign matter.
4. Clean burner with vacuum cleaner. DO NOT distort burner ports.
5. Reinstall burner in unit. Ensure that all the screws on the burner
angearetightenedsecurelysothatthegasketwillprovidea
good seal.
6. Also check for good flow of combustion and ventilating air
to the unit.
After placing the boiler in operation, check the ignition system
safety shut-off devices for proper operation. To accomplish this
with the main burner operating, close the valve on the manifold.
Within four seconds the main burner should extinguish. If this
does not occur immediately, discontinue gas supply by closing
main manual shut-off and call a qualified service agent to
correct the situation. If the burners extinguish, then light boiler
in accordance with lighting and operating instructions.
PREVENTATIVE MAINTENANCE